Methods and systems for producing ammonia synthesis catalysts

Abstract

Provided herein is a method comprising: (a) providing at least one rare-earth material in a chamber, (b) providing at least one support material in the chamber, (c) creating an oxidant-free environment in the chamber, (d) grinding, milling, or crushing the at least one rare-earth material and the at least one support material, (e) providing a passivating gas to the chamber, and (f) passivating a layer of the rare-earth material..

Description

METHODS AND SYSTEMS FOR PRODUCING AMMONIA SYNTHESIS CATALYSTSBACKGROUND

[0001] Ammonia is produced by combining one nitrogen molecule with three hydrogen molecules. An ammonia synthesis catalyst may be supported by a support material to hold the catalyst in place. An ammonia synthesis catalyst may be passivated to mitigate the sensitivity of the catalyst.SUMMARY

[0002] Recognized herein is a need for improved methods and systems for producing ammonia (NH3) synthesis catalysts. Further recognized herein is a need for improved compositions for NH3 synthesis catalysts. NH3 synthesis catalysts may have varied capacities during NH3 synthesis for cleavage of the strong molecular dinitrogen bond and release of the produced NH3 molecule. Methods and systems which produce supported or passivated NH3 synthesis catalyst compositions may facilitate improved molecular dinitrogen bond cleavage or improved NH3 molecule release. Such methods, systems, and compositions may facilitate production of NH3 under mild reaction conditions, direct incorporation of the methods, systems, or compositions in existing NH3 production plants, more efficient operation of existing NH3 production plants, lowered production costs, production of NH3 outside of greenfield production plants, production of NH3 in greenfield production plants, or alignment with renewable energy configurations.

[0003] In one aspect, the present disclosure provides a method comprising: (a) providing at least one rare-earth material in a chamber. In some aspects, the method may further comprise (b) providing at least one support material in the chamber. In some aspects, the method may further comprise (c) creating an oxidant-free environment in the chamber. In some aspects, the method may further comprise (d) grinding, milling, or crushing the at least one rare-earth material and the at least one support material.

[0004] In some aspects, the method further comprises (e) providing a passivating gas to the chamber. In some aspects, the method may further comprise (f) passivating a layer of the rare- earth material.

[0005] In some aspects, the oxidant-free environment is at a positive pressure, a negative pressure, or an atmospheric pressure. In some aspects, the oxidant-free environment is at a positive pressure. In some aspects, the oxidant-free environment is at a negative pressure. In some aspects, the oxidant-free environment is at an atmospheric pressure.

[0006] In some aspects, (d) further comprises grinding, milling, or crushing by a mechanical process.-1- WSGR Docket No. 68554-702.101

[0007] In some aspects, (d) further comprises grinding, milling, or crushing by a mechanochemical process.

[0008] In some aspects, the mechanochemical process comprises a ball milling process.

[0009] In some aspects, the mechanochemical process comprises a disc milling process or a jaw crushing process.

[0010] In some aspects, the ball milling process comprises milling with a grinding jar, shaker mill, a mixer-type mill, a planetary mill, or a high-energy planetary mill.

[0011] In some aspects, the grinding jar comprises steel, zirconium, zirconia, or tungsten carbide.

[0012] In some aspects, the grinding jar contains milling balls, wherein the milling balls comprise steel, zirconium, zirconia, or tungsten carbide.

[0013] In some aspects, the milling balls comprise a diameter of at least about 0.1 mm to at least about 20 mm.

[0014] In some aspects, (d) further comprises producing a supported rare-earth material.

[0015] In some aspects, the supported rare-earth material comprises a supported rare-earth nitride.

[0016] In some aspects, the supported rare-earth material comprises the at least one rare-earth material and the at least one support material. In some aspects, the at least one rare-earth material is located on or is in direct contact with the at least one support material in a catalyst layer.

[0017] In some aspects, the passivating gas comprises oxygen or moisture.

[0018] In some aspects, (e) further comprises providing the passivating gas at a gradient.

[0019] In some aspects, (f) comprises oxidizing the layer of the rare-earth material.

[0020] In some aspects, (f) further comprises producing a passivated layer of the rare-earth material at the exterior surface of the catalyst layer.

[0021] In some aspects, the passivated layer of the rare-earth material comprises a depth of less than about 5 nanometers.

[0022] In some aspects, the passivated layer of the rare-earth material comprises a depth of less than about 10 nanometers.

[0023] In some aspects, the passivated layer of the rare-earth material comprises a lanthanide oxide or a lanthanide oxynitride.

[0024] In some aspects, (f) further comprises producing a passivated rare-earth material.

[0025] In some aspects, (f) further comprises producing a supported and passivated rare-earth material.

[0026] In some aspects, the passivated rare-earth material comprises a passivated rare-earth nitride.

[0027] In some aspects, the passivated rare-earth material is stable for at least 30 weeks.-2- WSGR Docket No. 68554-702.101

[0028] In some aspects, the method further comprises (g) providing a promoter material to the chamber before (c).

[0029] In some aspects, the promoter material comprises an alkali metal, alkaline earth metal, or a group 13 element.

[0030] In some aspects, the at least one rare-earth material comprises a rare-earth precursor or a rare-earth metal.

[0031] In some aspects, the at least one rare-earth material comprises a rare-earth nitride.

[0032] In some aspects, the at least one rare-earth material comprises a lanthanide.

[0033] In some aspects, the at least one rare-earth material comprises a lanthanide salt, a lanthanide halide, a lanthanide chalcogenide, or a lanthanide pnictide.

[0034] In some aspects, the at least one rare-earth material comprises a lanthanide oxide, a lanthanide hydride, a lanthanide hydroxide, a lanthanide chloride, a lanthanide amide, or a lanthanide iodide.

[0035] In some aspects, the rare-earth nitride comprises lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) ytterbium (Yb), or lutetium (Lu).

[0036] In some aspects, the at least one rare-earth nitride comprises a lanthanide alloy comprising at least two lanthanides selected from the group consisting of: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0037] In some aspects, the at least one rare-earth nitride comprises a lanthanide nitride.

[0038] In some aspects, the at least one rare-earth nitride comprises lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), or lutetium nitride (LuN).

[0039] In some aspects, the at least one rare-earth nitride comprises a lanthanide nitride alloy comprising at least two lanthanide nitrides selected from the group consisting of: lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), and lutetium nitride (LuN).

[0040] In some aspects, the at least one support material is a non-porous solid or a porous solid.-3- WSGR Docket No. 68554-702.101

[0041] In some aspects, the at least one support material is porous, and wherein the at least one support material comprises a surface area from 1 square meter to 2,000 square meters per gram.

[0042] In some aspects, the at least one support material is catalytically active.

[0043] In some aspects, the at least one support material is catalytically passive.

[0044] In some aspects, the at least one support material comprises a diameter of at least about 5 nanometers to at least about 1 centimeter.

[0045] In some aspects, the at least one support material comprises a transition metal, a carbide, an oxide, a nitride, or a carbon allotrope.

[0046] In some aspects, the at least one support material does not comprise ruthenium (Ru).

[0047] In some aspects, the oxidant-free environment is (i) a vacuum, (ii) an inert atmosphere, (iii) an argon atmosphere, or (iv) a nitrogen atmosphere. In some aspects, the oxidant-free environment is a vacuum. In some aspects, the oxidant-free environment is an inert atmosphere. In some aspects, the oxidant-free environment is an argon atmosphere. In some aspects, the oxidant-free environment is a nitrogen atmosphere.

[0048] In some aspects, the nitrogen atmosphere comprises molecular nitrogen N2 or a nitrogen species.

[0049] In one aspect, the present disclosure provides a system comprising (a) a chamber that receives at least one rare-earth material and at least one support material. The system may further comprise (b) a source of an oxidant-free atmosphere that creates an oxidant-free environment in the chamber. The system may further comprise (c) a grinding, milling, or crushing apparatus that grinds, mills, or crushes the at least one rare-earth nitride and the at least one support material.

[0050] In some aspects, the source of the oxidant-free atmosphere creates the oxidant-free environment at a positive pressure, a negative pressure, or an atmospheric pressure.

[0051] In some aspects, the oxidant-free environment is at a positive pressure, a negative pressure, or an atmospheric pressure. In some aspects, the oxidant-free environment is at a positive pressure. In some aspects, the oxidant-free environment is at a negative pressure. In some aspects, the oxidant-free environment is at an atmospheric pressure.

[0052] In some aspects, the oxidant-free environment is (i) a vacuum, (ii) an inert atmosphere, (iii) an argon atmosphere, or (iv) a nitrogen atmosphere. In some aspects, the oxidant-free environment is a vacuum. In some aspects, the oxidant-free environment is an inert atmosphere. In some aspects, the oxidant-free environment is an argon atmosphere. In some aspects, the oxidant-free environment is a nitrogen atmosphere.

[0053] In some aspects, the chamber further receives a media that mills, grinds, or crushes the at least one rare-earth material and the at least one support material.-4- WSGR Docket No. 68554-702.101

[0054] In some aspects, the grinding, milling, or crushing apparatus grinds, mills, or crushes by a mechanical process.

[0055] In some aspects, the grinding, milling, or crushing apparatus grinds, mills, or crushes by a mechanochemical process.

[0056] In some aspects, the mechanochemical process comprises a ball milling process.

[0057] In some aspects, the mechanochemical process comprises a disc milling process or a jaw crushing process.

[0058] In some aspects, the ball milling process comprises milling with a grinding jar, shaker mill, a mixer-type mill, a planetary mill, or a high-energy planetary mill.

[0059] In some aspects, the grinding jar comprises steel, zirconium, zirconia, or tungsten carbide.

[0060] In some aspects, the grinding jar contains milling balls, wherein the milling balls comprise steel, zirconium, zirconia, or tungsten carbide.

[0061] In some aspects, the milling balls comprise a diameter of at least about 0.1 mm to at least about 20 mm.

[0062] In some aspects, the grinding, milling, or crushing apparatus produces a supported rare- earth material.

[0063] In some aspects, the supported rare-earth material comprises a supported rare-earth nitride.

[0064] In some aspects, the supported rare-earth material comprises the at least one rare-earth material and the at least one support material. In some aspects, the at least one rare-earth material is located on or is in direct contact with the at least one support material in a catalyst layer.

[0065] In some aspects, the system further comprises (d) a source of a passivating gas, wherein the passivating gas passivates a layer of the rare-earth material.

[0066] In some aspects, the passivating gas comprises oxygen or moisture.

[0067] In some aspects, the source of the passivating gas provides the passivating gas at a gradient.

[0068] In some aspects, the source of the passivating gas oxidizes the layer of the rare-earth material.

[0069] In some aspects, the source of the passivating gas produces a passivated layer of the rare- earth material at the exterior surface of the catalyst layer.

[0070] In some aspects, the passivated layer of the rare-earth material comprises a depth of less than about 5 nanometers.

[0071] In some aspects, the passivated layer of the rare-earth material comprises a depth of less than about 10 nanometers.-5- WSGR Docket No. 68554-702.101

[0072] In some aspects, the passivated layer of the rare-earth material comprises a lanthanide oxide or a lanthanide oxynitride.

[0073] In some aspects, the source of the passivating gas produces a passivated rare-earth material.

[0074] In some aspects, the system produces a supported and passivated rare-earth material.

[0075] In some aspects, the passivated rare-earth material comprises a passivated rare-earth nitride.

[0076] In some aspects, the passivated rare-earth material is stable for at least 30 weeks.

[0077] In some aspects, the chamber receives a promoter material.

[0078] In some aspects, the promoter material comprises an alkali metal, alkaline earth metal, or a group 13 element.

[0079] In some aspects, the at least one rare-earth material comprises a rare-earth precursor or a rare-earth metal.

[0080] In some aspects, the at least one rare-earth material comprises a rare-earth nitride.

[0081] In some aspects, the at least one rare-earth material comprises a lanthanide.

[0082] In some aspects, the at least one rare-earth material comprises a lanthanide salt, a lanthanide halide, a lanthanide chalcogenide, or a lanthanide pnictide.

[0083] In some aspects, the rare-earth nitride comprises lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) ytterbium (Yb), or lutetium (Lu).

[0084] In some aspects, the at least one rare-earth nitride comprises a lanthanide alloy comprising at least two lanthanides selected from the group consisting of: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0085] In some aspects, the at least one rare-earth nitride comprises a lanthanide nitride.

[0086] In some aspects, the at least one rare-earth nitride comprises lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), or lutetium nitride (LuN).

[0087] In some aspects, the at least one rare-earth nitride comprises a lanthanide nitride alloy comprising at least two lanthanide nitrides selected from the group consisting of: lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN),-6- WSGR Docket No. 68554-702.101samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), and lutetium nitride (LuN).

[0088] In some aspects, the at least one support material is a non-porous solid or a porous solid.

[0089] In some aspects, the at least one support material is porous, and wherein the at least one support material comprises a surface area from 1 square meter to 2,000 square meters per gram.

[0090] In some aspects, the at least one support material is catalytically active.

[0091] In some aspects, the at least one support material is catalytically passive.

[0092] In some aspects, the at least one support material comprises a diameter of at least about 5 nanometers to at least about 1 centimeter.

[0093] In some aspects, the at least one support material comprises a transition metal, a carbide, an oxide, a nitride, or a carbon allotrope.

[0094] In some aspects, the at least one support material does not comprise ruthenium (Ru).

[0095] In some aspects, the nitrogen atmosphere comprises molecular nitrogen N2 or a nitrogen species.

[0096] In another aspect, the present disclosure provides a method comprising: (a) providing at least one rare-earth material or a supported rare-earth material in a chamber. In some aspects, the method may further comprise (c) creating an oxidant-free environment in the chamber. In some aspects, the method may further comprise (e) providing a passivating gas to the chamber. In some aspects, the method may further comprise (f) passivating a layer of the rare-earth material or the supported rare-earth material.

[0097] In some aspects, (a) comprises providing the at least one rare-earth material in the chamber. In some aspects, the method may further comprise (b) providing at least one support material in the chamber after (a).

[0098] In some aspects, (a) comprises providing the at least one rare-earth material in the chamber. In some aspects, the method may further comprise (d) grinding or milling or crushing the at least one rare-earth material and the at least one support material after (c).

[0099] In some aspects, the oxidant-free environment is at a positive pressure, a negative pressure, or an atmospheric pressure. In some aspects, the oxidant-free environment is at a positive pressure. In some aspects, the oxidant-free environment is at a negative pressure. In some aspects, the oxidant-free environment is at an atmospheric pressure.

[0100] In some aspects, (d) further comprises grinding, milling, or crushing by a mechanical process.

[0101] In some aspects, (d) further comprises grinding, milling, or crushing by a mechanochemical process.-7- WSGR Docket No. 68554-702.101

[0102] In some aspects, the mechanochemical process comprises a ball milling process.

[0103] In some aspects, the mechanochemical process comprises a disc milling process or a jaw crushing process.

[0104] In some aspects, the ball milling process comprises milling with a grinding jar, shaker mill, a mixer-type mill, a planetary mill, or a high-energy planetary mill.

[0105] In some aspects, the grinding jar comprises steel, zirconium, zirconia, or tungsten carbide.

[0106] In some aspects, the grinding jar contains milling balls, wherein the milling balls comprise steel, zirconium, zirconia, or tungsten carbide.

[0107] In some aspects, the milling balls comprise a diameter of at least about 0.1 mm to at least about 20 mm.

[0108] In some aspects, (d) further comprises producing a supported rare-earth material.

[0109] In some aspects, the supported rare-earth material comprises a supported rare-earth nitride.

[0110] In some aspects, the supported rare-earth material comprises the at least one rare-earth material and the at least one support material. In some aspects, the at least one rare-earth material is located on or is in direct contact with the at least one support material in a catalyst layer.[oni] In some aspects, the passivating gas comprises oxygen or moisture.

[0112] In some aspects, (e) further comprises providing the passivating gas at a gradient.

[0113] In some aspects, (f) comprises oxidizing the layer of the rare-earth material.

[0114] In some aspects, (f) further comprises producing a passivated layer of the rare-earth material at the exterior surface of the catalyst layer.

[0115] In some aspects, the passivated layer of the rare-earth material comprises a depth of less than about 5 nanometers.

[0116] In some aspects, the passivated layer of the rare-earth material comprises a depth of less than about 10 nanometers.

[0117] In some aspects, the passivated layer of the rare-earth material comprises a lanthanide oxide or a lanthanide oxynitride.

[0118] In some aspects, (f) further comprises producing a passivated rare-earth material.

[0119] In some aspects, (f) further comprises producing a supported and passivated rare-earth material.

[0120] In some aspects, the passivated rare-earth material comprises a passivated rare-earth nitride.

[0121] In some aspects, the passivated rare-earth material is stable for at least 30 weeks.

[0122] In some aspects, the method further comprises (g) providing a promoter material to the chamber before (c).-8- WSGR Docket No. 68554-702.101

[0123] In some aspects, the promoter material comprises an alkali metal, alkaline earth metal, or a group 13 element.

[0124] In some aspects, the at least one rare-earth material comprises a rare-earth precursor or a rare-earth metal.

[0125] In some aspects, the at least one rare-earth material comprises a rare-earth nitride.

[0126] In some aspects, the at least one rare-earth material comprises a lanthanide.

[0127] In some aspects, the at least one rare-earth material comprises a lanthanide salt, a lanthanide halide, a lanthanide chalcogenide, or a lanthanide pnictide.

[0128] In some aspects, the rare-earth nitride comprises lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) ytterbium (Yb), or lutetium (Lu).

[0129] In some aspects, the at least one rare-earth nitride comprises a lanthanide alloy comprising at least two lanthanides selected from the group consisting of: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0130] In some aspects, the at least one rare-earth nitride comprises a lanthanide nitride.

[0131] In some aspects, the at least one rare-earth nitride comprises lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), or lutetium nitride (LuN).

[0132] In some aspects, the at least one rare-earth nitride comprises a lanthanide nitride alloy comprising at least two lanthanide nitrides selected from the group consisting of: lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), and lutetium nitride (LuN).

[0133] In some aspects, the at least one support material is a non-porous solid or a porous solid.

[0134] In some aspects, the at least one support material is porous, and wherein the at least one support material comprises a surface area from 1 square meter to 2,000 square meters per gram.

[0135] In some aspects, the at least one support material is catalytically active.

[0136] In some aspects, the at least one support material is catalytically passive.-9- WSGR Docket No. 68554-702.101

[0137] In some aspects, the at least one support material comprises a diameter of at least about 5 nanometers to at least about 1 centimeter.

[0138] In some aspects, the at least one support material comprises a transition metal, a carbide, an oxide, a nitride, or a carbon allotrope.

[0139] In some aspects, the at least one support material does not comprise ruthenium (Ru).

[0140] In some aspects, the oxidant-free environment is (i) a vacuum, (ii) an inert atmosphere, (iii) an argon atmosphere, or (iv) a nitrogen atmosphere. In some aspects, the oxidant-free environment is a vacuum. In some aspects, the oxidant-free environment is an inert atmosphere. In some aspects, the oxidant-free environment is an argon atmosphere. In some aspects, the oxidant-free environment is a nitrogen atmosphere.

[0141] In some aspects, the nitrogen atmosphere comprises molecular nitrogen N2 or a nitrogen species.

[0142] In another aspect, the present disclosure provides a composition comprising at least one rare-earth material and at least one support material. In some aspects, the at least one rare-earth material is located on or is in direct contact with the at least one support material in a catalyst layer. In some aspects, the at least one rare-earth material comprises a passivated layer at the exterior surface of the catalyst layer.

[0143] In some aspects, the passivated layer of the rare-earth material comprises a depth of less than about 5 nanometers.

[0144] In some aspects, the passivated layer of the rare-earth material comprises a depth of less than about 10 nanometers.

[0145] In some aspects, the passivated layer of the rare-earth material comprises a lanthanide oxide or a lanthanide oxynitride.

[0146] In some aspects, the composition is stable for at least 30 weeks.

[0147] In some aspects, the at least one rare-earth material comprises a rare-earth precursor or a rare-earth metal.

[0148] In some aspects, the at least one rare-earth material comprises a rare-earth nitride.

[0149] In some aspects, the at least one rare-earth material comprises a lanthanide.

[0150] In some aspects, the at least one rare-earth material comprises a lanthanide salt, a lanthanide halide, a lanthanide chalcogenide, or a lanthanide pnictide.

[0151] In some aspects, the rare-earth nitride comprises lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) ytterbium (Yb), or lutetium (Lu).-10- WSGR Docket No. 68554-702.101

[0152] In some aspects, the at least one rare-earth nitride comprises a lanthanide alloy comprising at least two lanthanides selected from the group consisting of: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0153] In some aspects, the at least one rare-earth nitride comprises a lanthanide nitride.

[0154] In some aspects, the at least one rare-earth nitride comprises lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), or lutetium nitride (LuN).

[0155] In some aspects, the at least one rare-earth nitride comprises a lanthanide nitride alloy comprising at least two lanthanide nitrides selected from the group consisting of: lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), and lutetium nitride (LuN).

[0156] In some aspects, the at least one support material is a non-porous solid or a porous solid.

[0157] In some aspects, the at least one support material is porous, and wherein the at least one support material comprises a surface area from 1 square meter to 2,000 square meters per gram.

[0158] In some aspects, the at least one support material is catalytically active.

[0159] In some aspects, the at least one support material is catalytically passive.

[0160] In some aspects, the at least one support material comprises a diameter of at least about 5 nanometers to at least about 1 centimeter.

[0161] In some aspects, the at least one support material comprises a transition metal, a carbide, an oxide, a nitride, or a carbon allotrope.

[0162] In some aspects, the at least one support material does not comprise ruthenium (Ru).

[0163] Another aspect of the present disclosure provides a system comprising one or more computer processors and computer memory coupled thereto. The computer memory comprises machine executable code that, upon execution by the one or more computer processors, implements any of the methods above or elsewhere herein.

[0164] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of-11- WSGR Docket No. 68554-702.101modifications in various obvious respects, all without departing from the disclosure.Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.INCORPORATION BY REFERENCE

[0165] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and / or take precedence over any such contradictory material.BRIEF DESCRIPTION OF THE DRAWINGS

[0166] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings (also “Figure” and “FIG.” herein), of which:

[0167] FIGs. 1A-1C depict methods for producing NH3 synthesis catalysts, per one or more embodiments described herein;

[0168] FIG. 1A shows a flow diagram depicting a method for producing a supported rare-earth material, per one or more embodiments described herein;

[0169] FIG. IB shows a flow diagram depicting a method for producing a passivated rare-earth material, per one or more embodiments described herein;

[0170] FIG. 1C shows a flow diagram depicting a method for producing a supported and passivated rare-earth material, per one or more embodiments described herein;

[0171] FIGs. 2A-2B show diagrams of systems for producing a supported or passivated rare- earth material, per one or more embodiments described herein;

[0172] FIG. 2A shows a diagram of a system for producing a supported or passivated rare-earth material comprising a single chamber, per one or more embodiments described herein;

[0173] FIG. 2B shows a diagram of a system for producing a supported or passivated rare-earth material comprising more than one chamber, per one or more embodiments described herein;

[0174] FIGs. 3A-3D depict characteristics of passivated rare earth materials, as described herein;

[0175] FIG. 3A shows a transmission electron microscopy (TEM) image of passivated rare-earth materials, per one or more embodiments described herein;-12- WSGR Docket No. 68554-702.101

[0176] FIG. 3B shows a graph depicting X-ray diffraction (XRD) patterns of passivated rare- earth materials, per one or more embodiments described herein;

[0177] FIG. 3C shows an image of rare-earth materials upon exposure to air, per one or more embodiments described herein;

[0178] FIG. 3D shows an image of passivated rare-earth materials upon exposure to air, per one or more embodiments described herein;

[0179] FIG. 4 shows a chart depicting normalized NH3 synthesis rates for different NH3 synthesis catalysts, per one or more embodiments described herein; and

[0180] FIG. 5 shows an example computer system configured to implement the systems, the methods, the computer-readable media, and the techniques disclosed herein, per one or more embodiments described herein.DETAILED DESCRIPTION

[0181] While various embodiments of the invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed.

[0182] Whenever the term “at least,” “greater than,” or “greater than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “at least,” “greater than” or “greater than or equal to” applies to each of the numerical values in that series of numerical values. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.

[0183] Whenever the term “no more than,” “less than,” or “less than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “no more than,” “less than,” or “less than or equal to” applies to each of the numerical values in that series of numerical values. For example, less than or equal to 3, 2, or 1 is equivalent to less than or equal to 3, less than or equal to 2, or less than or equal to 1.

[0184] Certain inventive embodiments herein contemplate numerical ranges. When ranges are present, the ranges include the range endpoints. Additionally, every sub range and value within the range is present as if explicitly written out. The term “about” or “approximately” may mean within an acceptable error range for the particular value, which will depend in part on how the value is measured or determined, e.g., the limitations of the measurement system. For example, “about” may mean within 1 or more than 1 standard deviation, per the practice in the art. Alternatively, “about” may mean a range of up to 20%, up to 10%, up to 5%, or up to 1% of a given value. Where particular values are described in the application and claims, unless-13- WSGR Docket No. 68554-702.101otherwise stated the term “about” meaning within an acceptable error range for the particular value may be assumed.

[0185] Provided herein are methods and systems useful for producing NH3 synthesis catalysts. Further provided herein are compositions for supported or passivated NH3 synthesis catalysts. These methods, systems, and compositions may improve production of ammonia or catalysts used in NH3 synthesis or production. These methods, systems, and compositions may facilitate improved molecular dinitrogen bond cleavage, improved NH3 molecule release, or the use of milder temperature and pressure conditions during NH3 synthesis or production.

[0186] NH3 is one of the largest industrially produced chemicals globally. Over 200 million tons of NH3 are produced per year. NH3 is primarily used in fertilizers. There is growing interest in using NH3 as a hydrogen storage carrier and using “green ammonia” as a carbon-neutral fuel.

[0187] In some instances, industrial NH3 production leverages the Haber-Bosch process and harsh conditions to synthesize NH3. The multi-step reaction utilizes dissociation and association mechanisms of hydrogen (H2) and molecular dinitrogen (N2) on the surface of a catalyst to form and release NH3. The harsh conditions may comprise high pressures (e.g., over 100 atmospheres) and high temperatures (e.g., over 400 °C). Industrial transition metal catalysts (e.g., iron-based catalysts or ruthenium-based catalysts) may be limited in facilitating facile cleavage of the strong N2 bond or facile release of the final product NH3. These limitations may place a fundamental limit on the maximum activity of some catalysts. Thus, industrial transition metal catalysts may not facilitate efficient NH3 synthesis.

[0188] Industrial NH3 synthesis catalysts include oxide melts, which may be formed by melting iron oxides (e.g., magnetite or wurtzite) together with various promoter materials. The promoter material may comprise an alkali metal, alkaline earth metal, or a group 13 element. The group 13 element may comprise boron, aluminum, gallium, indium, thallium, or nihonium. The promoter material may comprise lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), beryllium (Be), calcium (Ca), magnesium (Mg), barium (Ba), aluminium (Al), aluminum nitride (AIN), aluminum oxide (AI2O3), potassium superoxide (K2O), calcium oxide (CaO), magnesium oxide (MgO), or silicon dioxide (SiCh). During production of a NH3 synthesis catalyst, the oxide melt may be solidified, crushed down, and screened to the final pellet size to be used in a reactor for NH3 synthesis. The final pellet size may be on a millimeter to a centimeter scale. The final pellet size may be on a millimeter scale. The final pellet size may be on a centimeter scale. The iron oxide pellets may be carefully reduced to a highly active porous iron metal form. The reduction step may be performed in an NH3 synthesis reactor under standard synthesis gas (e.g., 75% H2, 25% N2) flow under a temperature ramp recipe. Such in-situ reduction may be limited by the production of water during the reduction step, as well as space velocity and heating-14- WSGR Docket No. 68554-702.101limitations of the synthesis reactor. Alternative processes may be used to “pre-reduce” the iron oxide pellets with bespoke equipment, which may optimize the reduction conditions for maximum iron oxide catalytic activity.

[0189] Pre-reduced catalysts must be passivated for transport and loading into the synthesis reactor. Passivation of the pre-reduced catalysts may be performed via a controlled oxidation process, which may form a thin protective skin oxide on the activated iron catalyst. The oxidation process may be performed by flowing a low oxygen concentration (e.g., about 1% mol), and gradually increasing the concentration up to atmospheric concentration (e.g., about 21% mol) over time. The in-situ activation process for such pre-reduced catalysts may be much shorter, offsetting the additional cost of processing.

[0190] The dissociation of N2 molecules, which contain bonds among the strongest in nature, is one of the rate-limiting process steps of NH3 synthesis. Atomically clean lanthanide metals, in layers with nanometric thickness, break the N2 bond under mild conditions (e.g., ambient temperature or less than or equal to about one atmosphere of pressure). Upon breaking the N2 bond, the lanthanide is converted into lanthanide nitride. (EP3649080B1, Ammonia Production Method). Exposing a surface of a layer or thin film of a rare-earth material to hydrogen may result in the formation of NH3. (J.R. Chan, et al., Facile dissociation of molecular nitrogen using lanthanide surfaces: Towards ambient temperature ammonia synthesis, Phys. Rev. Mater., 4, 115003 (2020)). Rare-earth materials in powder form showing strong catalytic activity towards NH3 synthesis may be suited for industrial purposes. Adjustments to a range of physical and chemical properties of such powders may make the powders appropriate for industrial applications.

[0191] FIG. 1 A shows a flow diagram depicting a method for producing a supported rare-earth material. In one embodiment, a rare-earth material 101 and a support material 102 may be placed in an oxidant-free environment 103, then ground, milled, or crushed 104 to produce a supported rare-earth material 105.

[0192] Examples of the rare-earth material 101 may include a rare-earth element or a rare-earth nitride, as described further herein. The rare-earth material 101 may show strong catalytic activity towards NH3 synthesis, as described further herein. Examples of the support material 102 may include a transition metal, a carbide, an oxide, a nitride, or a carbon allotrope. The support material 102 may have a large surface area that facilitates dispersal of the rare-earth material 101 on the support material 102, as described further herein. The oxidant-free environment 103 may be achieved by providing a vacuum, an inert atmosphere, an argon atmosphere, or a nitrogen atmosphere, as described further herein. The rare-earth material 101 and the support material 102-15- WSGR Docket No. 68554-702.101may be ground, milled, or crushed 104 by a grinding, milling, or crushing apparatus, as described further herein.

[0193] FIG. IB shows a flow diagram depicting a method for producing a passivated rare-earth material. In one embodiment, the rare-earth material 101 may be placed in an oxidant-free environment 103, then treated with a passivating gas 106 to produce a rare-earth material with a passivated layer at an exterior surface of the rare-earth material (e.g., a passivated rare-earth material) 107. In another embodiment, the supported rare-earth material 105 may be placed in an oxidant-free environment 103, then treated with the passivating gas 106 to produce a supported and passivated rare-earth material 108. Examples of the passivating gas 106 may comprise oxygen or moisture, as described further herein.

[0194] FIG. 1C shows a flow diagram depicting a method for producing a supported and passivated rare-earth material. In one embodiment, the rare-earth material 101 and the support material 102 may be placed in an oxidant-free environment 103, then ground, milled, or crushed 104 to produce the supported rare-earth material 105. The supported rare-earth material 105 in the oxidant-free environment 103 may then be treated with the passivating gas 106 to produce the supported and passivated rare-earth material 108.Rare-Earth Materials

[0195] A rare-earth material may comprise rare-earth metals (REM). The REM are a set of 17 metallic elements, and comprise the 15 lanthanide (Ln) elements along with scandium and yttrium. The Ln elements comprise the elements with atomic numbers from 57 (lanthanum) to 71 (lutetium). The Ln elements are the only stable elements with f-shells filled to varying extents. Thus, the Ln elements have a large magnetic moment (e.g., Ln elements may be strong magnets). The Ln elements can be used in high-tech applications (e.g., wind turbines, electric vehicles, catalysis, consumer displays or lighting systems).

[0196] When combined with nitrogen, the Ln elements form a mononitride: lanthanide nitrides (LnN). The LnN possess a semiconducting nature and most of them have an intrinsic ferromagnetic ground state. Thus, the LnN possess inherent and unique complementary magnetic and electronic properties. These complementary properties may make the LnN attractive for spintronics activity or future computing applications. Such applications focus on thin films, which may be an architecture of a spintronics device. With the emergence of new applications in the field of catalysis for NfL synthesis and advanced nuclear fuel cycles, the LnN may be utilized in alternative forms (e.g., powders, pellets, or bulks). The catalytic process of NfL synthesis may not involve the magnetic properties of the LnN.

[0197] In some aspects, a rare-earth material may comprise a rare-earth precursor. The rare-earth precursor may comprise a lanthanide salt, a lanthanide halide, a lanthanide chalcogenide,-16- WSGR Docket No. 68554-702.101lanthanide borohydride, a lanthanide alkyl, or a lanthanide pnictide. The rare-earth precursor may comprise a lanthanide oxide, a lanthanide hydride, a lanthanide hydroxide, a lanthanide chloride, a lanthanide amide, or a lanthanide iodide. The rare-earth material may comprise a rare-earth metal. The rare-earth material may comprise a lanthanide salt, a lanthanide halide, a lanthanide chalcogenide, lanthanide borohydride, a lanthanide alkyl, or a lanthanide pnictide. The rare-earth material may comprise a lanthanide oxide, a lanthanide hydride, a lanthanide hydroxide, a lanthanide chloride, a lanthanide amide, or a lanthanide iodide.

[0198] In some aspects, a rare-earth material may comprise a rare-earth nitride. The rare-earth nitride may comprise a lanthanide. The lanthanide may comprise (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) ytterbium (Yb), or lutetium (Lu). The rare-earth nitride may comprise a lanthanide alloy comprising at least two lanthanides selected from the group consisting of: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0199] The rare-earth nitride may comprise a lanthanide nitride. The rare-earth nitride may comprise lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), or lutetium nitride (LuN). The rare-earth nitride may comprise a lanthanide nitride alloy comprising at least two lanthanide nitrides selected from the group consisting of: lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), and lutetium nitride (LuN).Chambers

[0200] The NH3 synthesis catalysts described herein may be produced in a chamber 201 or in more than one chamber 201, 205 (FIG. 2). The chamber 201, 205 may be pressurized. The chamber 201, 205 may be pressurized or depressurized during operation. The chamber 201, 205 may be gradually pressurized or depressurized during operation. The chamber 201, 205 may be pressurized or depressurized to a pressure of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more, bar. The chamber 201, 205 may be heated or cooled during operation. The chamber 201, 205 may be gradually heated or cooled during operation. The chamber 201, 205 may be heated or cooled to a temperature of at least about -250 °C, -225 °C, -200 °C, -175 °C, -150 °C, -125 °C, -100 °C, -90 -17- WSGR Docket No. 68554-702.101°C, -80 °C, -70 °C, -60 °C, -50 °C, -40 °C, -30 °C, -20 °C, -10 °C, 0 °C, 25 °C, 50 °C, 75 °C, 100 °C, 125 °C, 150 °C, 175 °C, 200 °C, 225 °C, 250 °C, 275 °C, 300 °C, 325 °C, 350 °C, 375 °C, 400 °C, 425 °C, 450 °C, 475 °C, 500 °C, or more.

[0201] FIGs. 2A-2B show diagrams of systems for producing a supported or passivated rare- earth material. FIG. 2 A shows a diagram of a system for producing a supported or passivated rare-earth material comprising a single chamber 201. The system may comprise a chamber 201. The chamber 201 may receive at least one rare-earth material and at least one support material. The system may further comprise a source 202 of an oxidant-free environment that may create an oxidant-free atmosphere in the chamber 201. The source 202 of the oxidant-free environment may create an atmosphere at a positive pressure, a negative pressure, or an atmospheric pressure. The chamber 201 may further comprise a grinding, milling, or crushing apparatus 203. The chamber 201 may receive a media that mills, grinds, or crushes the at least one rare-earth material and the at least one support material within the grinding, milling, or crushing apparatus 203. The grinding, milling, or crushing apparatus 203 may grind, mill, or crush the at least one rare-earth material and the at least one support material. The grinding, milling, or crushing apparatus 203 may produce a supported rare-earth material. The system may further comprise a source 204 of a passivating gas. The source 204 of the passivating gas may passivate a layer of the rare-earth material. The source 204 of the passivating gas may produce a passivated rare- earth material. The source 204 of the passivating gas may produce a supported and passivated rare-earth material.

[0202] FIG. 2B shows a diagram of a system for producing a supported or passivated rare-earth material comprising at least two chambers 201 and 205.

[0203] In some aspects, the system may comprise a chamber 201. The chamber 201 may receive at least one rare-earth material and at least one support material. The system may further comprise a source 202 of an oxidant-free environment that may create an oxidant-free atmosphere in the chamber 201. The source 202 of the oxidant-free environment may create an atmosphere at a positive pressure, a negative pressure, or an atmospheric pressure. The chamber 201 may further comprise a grinding, milling, or crushing apparatus 203. The chamber 201 may receive a media that mills, grinds, or crushes the at least one rare-earth material and the at least one support material within the grinding, milling, or crushing apparatus 203. The grinding, milling, or crushing apparatus 203 may grind, mill, or crush the at least one rare-earth nitride and the at least one support material. The grinding, milling, or crushing apparatus 203 may produce a supported rare-earth material. The system may further comprise a chamber 205. The chamber 205 may receive a rare-earth material or a supported rare-earth material. The system may further comprise a source 202 of an oxidant-free environment that may create an oxidant-free-18- WSGR Docket No. 68554-702.101atmosphere in the chamber 205. The source 202 of the oxidant-free environment may create an atmosphere at a positive pressure, a negative pressure, or an atmospheric pressure. The system may further comprise a source 204 of a passivating gas. The source 204 of the passivating gas may passivate a layer of the rare-earth material or the supported rare-earth material in the chamber 205.

[0204] In some aspects, the chamber 205 may receive a rare-earth nitride. The system may further comprise a source 202 of an oxidant-free environment that may create an oxidant-free atmosphere in the chamber 205. The source 202 of the oxidant-free environment may create an atmosphere at a positive pressure, a negative pressure, or an atmospheric pressure. The system may further comprise a source 204 of a passivating gas. The source 204 of the passivating gas may passivate a layer of the rare-earth material in the chamber 205. The system may further comprise a chamber 201. The chamber 201 may receive at least one rare-earth material or passivated rare-earth material and at least one support material. The system may further comprise a source 202 of an oxidant-free environment that may create an oxidant-free atmosphere in the chamber 201. The source 202 of the oxidant-free environment may create an atmosphere at a positive pressure, a negative pressure, or an atmospheric pressure. The chamber 201 may further comprise a grinding, milling, or crushing apparatus 203. The chamber 201 may receive a media that mills, grinds, or crushes the at least one rare-earth material and the at least one support material within the grinding, milling, or crushing apparatus 203. The grinding, milling, or crushing apparatus 203 may grind, mill, or crush the at least one rare-earth nitride and the at least one support material. The grinding, milling, or crushing apparatus 203 may produce a supported rare-earth nitride. The grinding, milling, or crushing apparatus 203 may produce a supported and passivated rare-earth nitride.

[0205] The chamber 201, 205 or the grinding, milling, or crushing apparatus 203 may be airtight. The chamber 201, 205 or the grinding, milling, or crushing apparatus 203 may be pressurized. The chamber 201, chamber 205, or the grinding, milling, or crushing apparatus 203 may be at the same pressure. The chamber 201, the chamber 205, or the grinding, milling, or crushing apparatus 203 may be at different pressures. The chamber 201, the chamber 205, or the grinding, milling, or crushing apparatus 203 may be at the same temperature. The chamber 201, the chamber 205, or the grinding, milling, or crushing apparatus 203 may be at different temperatures.

[0206] The chamber 201, 205 or the apparatus grinding, milling, or crushing 203 may have a volume of at least about 10'5m3to at least about 1 m3. The chamber 201, 205 or the apparatus grinding, milling, or crushing 203 may have a volume of at least about 1 to at least about 100 m3.-19- WSGR Docket No. 68554-702.101Oxidant-Free Environments

[0207] NH3 synthesis catalysts or precursors to NH3 synthesis catalysts may be inherently reactive: the NH3 synthesis reaction requires breaking the otherwise-inert triple bond in N2. Thus, catalysts or catalyst precursors, like the rare-earth material, may be sensitive to oxygenating compounds. Activated catalysts or catalyst precursors may react strongly with oxygenating compounds. Exposure to oxygenating compounds may occur when a catalyst or catalyst precursor encounters air. Oxygenating compounds may comprise oxygen, carbon dioxide, or moisture. Oxygenating compounds may deactivate the catalytic properties of a catalyst or catalyst precursor over time. Moisture may degrade industrial NH3 synthesis catalysts, including industrial pre-reduced iron catalysts. These oxidating effects may be exacerbated by an increased available surface area when a catalyst or catalyst precursor is in powder form. Deactivation of a catalyst or catalyst precursor may result in the loss of catalyst activity towards NH3 synthesis.

[0208] Rare-earth materials, like the LnN, may decompose or oxidize upon exposure to air. (FIGs. 3C-3D) For example, catalysts comprising pure lanthanide nitride powders may degrade completely within several hours when exposed to air due to oxygen or moisture sensitivity. Visual inspections of such powders after several hours show an expansion of the volume of the powders. A change in volume may indicate a loss of catalytic capacity of the powder. Visual inspections of such powders after several hours further show a change in the color of the powders. A color change may be from black to gray or white, or from black to orange or brown (e.g., with CeN). A color change may indicate a loss of catalytic capacity of the powder. Catalysts comprising pure lanthanide nitride powders may also tend to spark or be flammable upon exposure to air. These sensitivities may lead to environmental and safety issues during handling, transport, and storage of such powders.

[0209] NH3 synthesis catalysts comprising heavily oxidized rare-earth materials may not be readily reduced in an NH3 synthesis reactor under standard synthesis gas flow under a temperature ramp recipe. Thus, methods or systems for producing NH3 synthesis catalysts comprising rare-earth materials may be structured to avoid heavily oxidizing the rare-earth materials. In some aspects, mechanically reducing the size of large pieces or large pellets of a rare-earth material to a powder may be performed in an oxidant-free environment. The large pieces or large pellets of the rare-earth material may have a thin surface layer of oxidation before the mechanical process is performed. The resulting powder may be mixed with a promoter or passivated for transport and loading into the synthesis reactor without being pre-reduced.

[0210] An oxidant-free environment in the chamber may reduce the air sensitivity of NH3 synthesis catalysts or precursors to NH3 synthesis catalysts. An oxidant-free environment in the chamber may reduce the air sensitivity of the rare-earth material.-20- WSGR Docket No. 68554-702.101

[0211] In some aspects, an oxidant-free environment may be provided in a chamber used for producing an NH3 synthesis catalyst. The oxidant-free environment may be a vacuum. The oxidant-free environment may be an inert atmosphere. The oxidant-free environment may be an argon atmosphere. The oxidant-free environment may be a nitrogen atmosphere. The nitrogen atmosphere may comprise N2. The nitrogen atmosphere may comprise a nitrogen species.

[0212] The oxidant-free environment may be at a positive pressure, a negative pressure, or an atmospheric pressure. The source of the oxidant-free environment may create the oxidant-free environment at a positive pressure, a negative pressure, or an atmospheric pressure.Support of Rare-Earth Materials

[0213] Micrometric powders or nanometric particles (e.g., nanoparticles) may be too small for direct use as industrial NH3 synthesis catalysts. These nanoparticles or powders may have the propensity to sinter, resulting in reduced catalytic activity.

[0214] These powders may be shaped into a more appropriate form (e.g., pellets or coated on a support) for use in mid-scale or large-scale industrial NH3 reactors. Such forms may avoid sintering or reduced catalytic activity. NH3 synthesis catalysts used in fixed-bed NH3 reactors may be at least at the millimeter scale to avoid high-pressure drops in the reactor during NH3 synthesis. Support materials (or carrier materials) for NH3 synthesis catalysts may comprise a solid material with a large surface area that facilitates dispersal of the catalysts on the solid material. A support material may limit sintering of a powdered NH3 synthesis catalyst.

[0215] In some aspects, the at least one support material may be a non-porous solid or a porous solid. In other aspects, the at least one support material may be porous. The at least one support material may comprise a surface area from about 1 square meter to about 2,000 square meters per gram. The at least one support material may comprise a surface area of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, or more, square meters per gram.

[0216] The support material may be catalytically active. The support material may be catalytically passive.

[0217] In some aspects, the at least one support material may comprise a diameter of at least about 5 nanometers to at least about 1 centimeter. The at least one support material may comprise a diameter of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, or more, nanometers. The at least one support material may comprise a diameter of at least about 1,-21- WSGR Docket No. 68554-702.1012, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 60, 70, 80, 90,100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280,290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470,480, 490, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, or more, micrometers. The at least one support material may comprise a diameter of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, or more, millimeters. The at least one support material may comprise a diameter of at least about 1, 2, 3, 4, 5, or more, centimeters.

[0218] In some aspects, the at least one support material may comprise a transition metal, a carbide, an oxide, a nitride, or a carbon allotrope. The at least one support material may comprise iron (Fe), silicon carbide (SiC), aluminum nitride (AIN), or activated carbon. A support material may be selected to avoid leaching by the NFF synthesis catalyst from the support material. In some embodiments, the at least one support material may be ruthenium (Ru) free. Ruthenium- supported catalysts for NH3 synthesis have been known to leach from their support. (Zheng, Xiaoling, et al. "Effect of thermal and oxidative treatments of activated carbon on its surface structure and suitability as a support for barium-promoted ruthenium in ammonia synthesis catalysts." Carbon 40.14 (2002): 2597-2603.) The rare-earth materials disclosed herein may not leach from the support.

[0219] In some aspects of the methods described herein, (d) may comprise producing a supported rare-earth material. In some aspects of the methods, systems, or compositions described herein, the supported rare-earth material may comprise a supported rare-earth nitride. The supported rare-earth material may comprise the at least one rare-earth material and the at least one support material. The at least one rare-earth material may be located on the at least one support material in a catalyst layer. The at least one rare-earth material may be in direct contact with the at least one support material in a catalyst layer. The at least one rare-earth material may be located on or may be in direct contact with the at least one support material in a catalyst layer.

[0220] The methods and systems described herein may comprise a grinding, milling, or crushing apparatus that grinds, mills, or crushes the at least one rare-earth material. The methods and systems described herein may comprise a grinding, milling, or crushing apparatus that grinds, mills, or crushes the at least one rare-earth material and the at least one support material.

[0221] The grinding, milling, or crushing apparatus may produce a particle with a diameter of at least about 0.01 micrometer (pm) to at least about 1 pm. The grinding, milling, or crushing apparatus may produce a particle with a diameter of at least about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or more, pm. The grinding,-22- WSGR Docket No. 68554-702.101milling, or crushing apparatus may facilitate heating or cooling of the at least one rare-earth material and the at least one support material. The grinding, milling, or crushing apparatus may be pressurized to a pressure of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or more, bar. The grinding, milling, or crushing apparatus may be heated or cooled during operation. The grinding, milling, or crushing apparatus may be gradually heated or cooled during operation. The grinding, milling, or crushing apparatus may be cooled or heated to a temperature of at least about -250 °C, -225 °C, -200 °C, -175 °C, -150 °C, -125 °C, -100 °C, -90 °C, -80 °C, - 70 °C, -60 °C, -50 °C, -40 °C, -30 °C, -20 °C, -10 °C, 0 °C, 25 °C, 50 °C, 75 °C, 100 °C, 125 °C, 150 °C, 175 °C, 200 °C, 225 °C, 250 °C, 275 °C, 300 °C, 325 °C, 350 °C, 375 °C, 400 °C, 425 °C, 450 °C, 475 °C, 500 °C, or more.

[0222] Supported NH3 synthesis catalysts may be produced via mechanochemistry fabrication methods. Such methods may encompass a single step that facilitates both nitridation and coating of at least one rare-earth material on at least one support material. In some aspects, the at least one rare-earth material may be supported by the at least one support material via grinding, milling, or crushing by the grinding, milling, or crushing apparatus. In some aspects, the at least one rare-earth material may be supported by the at least one support material via dry grinding, dry milling, or dry crushing by the grinding, milling, or crushing apparatus. In some aspects, the at least one rare-earth material may be supported by the at least one support material via wet grinding, wet milling, or wet crushing by the grinding, milling, or crushing apparatus. The rare- earth material or the support material may be placed in a grinding, milling, or crushing apparatus with a wet grinding liquid.

[0223] Protocols for manufacturing NH3 synthesis catalysts on an industrial scale may be selected to guarantee an acceptable level of quality, control, or reliability. Such protocols may include hydrothermal treatments, precipitation, deposition-precipitation, and impregnation. Alternative NH3 synthesis catalyst manufacturing protocols may be developed to optimize superior properties of the manufactured catalyst or to optimize favorable economic or ecological characteristics of the manufacturing process.

[0224] Such alternative protocols may include mechanical processes or mechanochemical processes, like reactive extrusion or ball milling processes. Reactive extrusion or ball milling may provide simple and effective synthesis routes for solid catalyst materials and catalysts.

[0225] Mechanochemistry is a branch of chemistry involving the study of physico-chemical transformations generated by mechanical forces under various environments. Applications of mechanochemistry may include metallurgy, mechanochemical alloying, and synthesis of solid catalyst materials and catalysts. Mechanochemical synthesis of catalysts may involve the-23- WSGR Docket No. 68554-702.101preparation of materials with desired properties, like crystallization degree, morphology, phase composition, porosity, component distribution, or dispersion.

[0226] Ball milling may involve placing pieces of a material and a media into a cylindrical chamber and rotating the chamber around an axis. Ball milling may also involve non-cylindrical jars, rotation around multiple axes, or non-rotational motion (e.g., shaking). The material may be a support material. The material may be metal based. The material may be in chunks with a diameter of a few micrometers to a few centimeters. The media may comprise milling balls. The rotation of the chamber may cause the milling medium or grinding medium to grind the material, thus reducing the particle size of the material. The ball milling process may thus convert bulk materials to nanoparticles. These nanoparticles may be used directly as solid NH3 synthesis catalysts, or as raw materials for the subsequent manufacturing of NH3 synthesis catalysts.

[0227] In some aspects, the chamber 201 may receive a media that mills, grinds, or crushes the at least one rare-earth material and the at least one support material. In the methods described herein, (d) may comprise grinding, milling, or crushing by a mechanical process. In the methods described herein, (d) may comprise grinding, milling, or crushing by a mechanochemical process.

[0228] In some aspects, the mechanochemical process may comprise a ball milling process. The mechanochemical process may comprise a disc milling process or a jaw crushing process. The ball milling process may comprise milling with a grinding jar, shaker mill, a mixer-type mill, a planetary mill, or a high-energy planetary mill. The grinding jar may comprise steel, zirconium, zirconia, or tungsten carbide. The grinding jar may contain milling balls, the milling balls comprise steel, zirconium, zirconia, or tungsten carbide. The milling balls may comprise a diameter of at least about 0.1 millimeter (mm) to at least about 20 mm. The milling balls may comprise a diameter of at least about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more, mm.

[0229] As described herein, nanoparticles may have the propensity to sinter and may benefit from being supported. Processes for supporting catalysts on an industrial scale may include precipitation and impregnation — both of which may require several synthesis steps and postfabrication treatments. Mechanochemistry may provide a single-step process for supporting finely dispersed and nanosized catalysts on an industrial scale.

[0230] Supported catalysts may include supported metal nanoparticles and supported metal oxide nanoparticles. When desired supported catalysts cannot be obtained by a grinding process alone, further treatments (e.g., calcination, hydration, sorption, reduction) may facilitate the reaction. Mechanochemical synthesis of supported catalysts may be used for metal salts or metal-based precursors for the synthesis of the corresponding metal nanoparticles. Mechanochemical synthesis of supported catalysts may use coarse metal powders as precursors. For example, gold-24- WSGR Docket No. 68554-702.101may be dispersed as nanoparticles over an oxide support (e.g., TiCh, AI2O3, Fe2O3, or CO3O4), albeit under carbon monoxide oxidation reaction conditions (e.g., carbon monoxide and oxygen reaction gases) (Amrute etal., “Mechanochemical Synthesis of Catalytic Materials”, Chem. Eur. J. 2021, 27, 6819 - 6847.) Metal oxides may also be used as active phases deposited on supporting material by mechanochemical synthesis, for methanation, hydrogenation, or watersplitting applications.

[0231] In some aspects of the present disclosure, a single-step mechanochemical process may produce a supported NH3 synthesis catalyst. The methods, systems, and compositions described herein may provide for the dispersion of a rare-earth material in powder or particle form on a support material, without several synthesis steps or post-fabrication treatments. The methods, systems, and compositions described herein may provide for the use of a dry environment fabrication process. The methods, systems, and compositions described herein may provide for the use of a wet environment fabrication process. A powdered NH3 synthesis catalyst material may be coated on a support material at the same time as the powdered catalyst material is nitridated. The methods and systems described herein may facilitate production of a supported NH3 synthesis catalyst which produces NH3 when nitrogen (N2) and hydrogen (H2) reactants are provided. The compositions described herein may comprise a supported NH3 synthesis catalyst which produces NH3 when nitrogen (N2) and hydrogen (H2) reactants are provided. The methods, systems, and compositions described herein may provide for a supported rare-earth material which produces NH3 when nitrogen (N2) and hydrogen (H2) reactants are provided.

[0232] Ball milling of metal, metal nitrides, and metal oxide powders may cause an agglomeration phenomenon seen with powders or nanoparticles, in which milling may not progress without manually breaking of the powders or nanoparticles loose to free individually dispersed nanoparticles. Simultaneous ball milling and nitriding may avoid the agglomeration phenomenon. Simultaneous ball milling and nitriding may also limit sintering: there may be no notable change in the supported rare-earth catalysts before and after testing in the NH3 reactor, suggesting that sintering is rather limited when using supported rare-earth catalysts.Passivation of Rare-Earth Materials

[0233] As described herein, NH3 synthesis catalysts or precursors to NH3 synthesis catalysts, like the rare-earth material, may be sensitive to air exposure or may react strongly upon air exposure. Air may comprise oxygenating compounds, which may comprise oxygen, carbon dioxide, or moisture. Moisture may comprise a liquid (e.g., water) diffused in a small quantity as vapor, within a solid, or condensed on a surface. Oxygenating compounds may deactivate the catalytic properties of a catalyst or catalyst precursor over time, resulting in the loss of catalyst activity-25- WSGR Docket No. 68554-702.101towards NH3 synthesis. Rare-earth materials, like the LnN, may decompose or oxidize upon exposure to air, especially when in powder form.

[0234] Alternative fabrication methods or passivating materials or capping materials may minimize the sensitivity of rare-earth materials, especially in powder form, to air exposure. These strategies may cover the surface of the powder with a protection layer (e.g., passivation layer or passivated layer). The protection layer may avoid spontaneous ignition or degradation over time, thus avoiding the loss of catalytic activity towards NH3 synthesis. The protection layer may passivate the NH3 synthesis catalyst for storage, transport, and loading into a reactor for NH3 synthesis. The passivation layer may be removed from the powdered rare-earth material in the reactor under synthesis gas flow (e.g., H2 or N2) under temperature ramp recipes prior to the industrial synthesis of NH3.

[0235] Methods, systems, and compositions described herein may reduce the sensitivity of powdered rare-earth materials with a large surface area via passivation. Such passivated rare- earth materials may resist degradation upon exposure to air over time. Such passivated rare-earth materials may be non-flammable upon exposure to air.

[0236] Rare-earth materials in thin-film form may be protected from reactions with the ambient atmosphere via passivation with an effective capping layer. However, thin-film rare-earth materials may not be well-suited to industrial-scale NH3 synthesis.

[0237] Capping layers which may be removed in a vacuum may facilitate fundamental characterization techniques but may not facilitate efficient NH3 synthesis. Such techniques may comprise synchrotron-based measurements for electronic structure, or surface science tools for morphology characterization. Removal of a removable metallic capping layer may not modify the electrical characteristics, optical characteristics, or bulk structural properties of a rare-earth nitride material (EP3552231 Al, Rare Earth Nitride Structures and Devices and Method for Removing a Passivating Capping). The removal of such a removable metallic capping layer after air exposure may result in a thick lanthanide oxide layer. This thick lanthanide oxide layer may be thermally stable up to high temperatures, preventing use of the surface for efficient catalysis applications (M Le Ster, et al., Removable capping layer for air sensitive GdN, Nanotechnology 31 275709 (2020)).

[0238] The wax-binder approach may be used to form protection layers on powders and thin layers. The wax binder approach may improve air stability of NH3 synthesis catalysts during storage or transport. However, removal of the protection layers during NH3 synthesis involves challenges, like blockages or over-pressure in the reactor or residual contamination of the reactor.

[0239] Rare-earth material powders comprising a very thin passivated layer on the exterior surface of the powder may facilitate efficient NH3 synthesis.-26- WSGR Docket No. 68554-702.101

[0240] Lanthanide oxide compounds may be stable and difficult to reduce back to a metal form under harsh conditions that may used in reducing iron-based catalysts that may be used for NH3 synthesis. The conditions that may be used to reduce iron oxide to metal may be insufficient to reduce lanthanide oxides. (Gupta, C.K., Krishnamurthy, N. Oxide reduction processes in the preparation of rare-earth metals, Mining, Metallurgy & Exploration 30, 38-44 (2013)). Surprisingly, a powdered rare-earth material that has been partially oxidized (e.g. a lanthanide nitride powder comprising a thin lanthanide oxide layer) can still be used to synthesize NH3 under mild conditions.

[0241] FIGs. 3 A-3D depict characteristics of passivated rare earth materials. FIG. 3 A shows a transmission electron microscopy (TEM) image of a passivated rare-earth material. The passivated rare-earth material comprises erbium nitride passivated via the methods described herein. TEM shows lattice fringes in the interior of the passivated rare-earth material have a lattice spacing of 2.88 Angstroms, which corresponds to the face-centered cubic di l l lattice plane of erbium nitride. TEM also shows that the surface of the passivated rare-earth material is covered by a passivated layer. The dashed lines indicate the boundary between the rare-earth material (core material) and the passivated layer. The passivated layer comprises a thickness of about 1 nanometer. The atomic plane spacing in the passivated layer has a spacing of 3.43 Angstroms, which corresponds to the erbium oxide d01-10 lattice plane. The atomic plane spacing in the passivated layer has an observed lattice constant of 2.7 Angstroms, which corresponds to the erbium oxide d01-l 1 plane. Thus, the passivated rare-earth material comprises a rare-earth nitride and a passivated layer comprising a rare-earth oxide.

[0242] FIG. 3B shows a graph depicting X-ray diffraction (XRD) patterns of a passivated rare- earth material. The passivated rare-earth material in FIG. 3A is subjected to XRD using a conventional omega-2theta scan within Bragg-Brentano conditions. The graph depicts XRD patterns of passivated rare-earth materials (a) immediately following the passivation process described herein and (b) 26 weeks following the passivation process. Both (a) and (b) show only peaks corresponding to the face-centered cubic lattice of rare-earth materials (e.g., “111”, “200”, “220”, “311”, “222”, “400”, “331”, and “420”). The passivated layer may be too thin to be measured by XRD. No diffracted signals from other phases are observed at 0 weeks or 26 weeks, indicating no diffracted signals from other phases develop over time. No structural modification of the passivated rare-earth materials is observed. The relative XRD peak intensities of the crystallographic planes of the passivated rare-earth materials do not weaken over time. These results demonstrate how the passivated layer at the exterior surface of the rare-earth materials protects the rare-earth materials from reacting with the ambient atmosphere.-27- WSGR Docket No. 68554-702.101

[0243] FIG. 3C shows an image of a rare-earth material upon exposure to air. FIG. 3D shows an image of a passivated rare-earth material upon exposure to air. The rare-earth material comprises an erbium nitride powder, and the passivated rare-earth material comprises an erbium nitride powder passivated via the methods described herein. The rare-earth material powder demonstrated in FIG. 3C may spark and be flammable upon exposure to air. Visual inspections of the rare-earth material powder show an expansion of the volume of the powder after air exposure. Visual inspections of the rare-earth material powder also show a change in the color of the powder after air exposure. The passivated rare-earth material powder demonstrated in FIG. 3D does not spontaneously ignite when exposed to air. Visual inspections of the passivated rare- earth material powder show no change in color after air exposure. Thus, the passivated rare-earth material powder is more stable than the non-passivated rare-earth material powder.

[0244] In some aspects, a rare-earth material may be exposed to a passivating gas at a gradient. The gradient may first comprise a low concentration of the passivating gas, and the concentration may be gradually increased. Passivating the layer of the rare-earth material may produce a passivated layer of the rare-earth material at the exterior surface of the rare-earth material. The passivating gas may comprise oxygen or moisture. Following the exposure and the gradual increase, a thin passivated layer may result on the surface of the rare-earth material. The passivating gas may oxidize a thin layer on the surface of the rare-earth material to form the passivated layer. The rare-earth material may be in powder form, resulting in a thin passivated layer on the surface of the powder particulates. The remaining volume of the powder may still consist of the original rare-earth material. Exposure to the passivating gas may produce a passivated NEE synthesis catalyst comprising the passivated layer. Exposure to the passivating gas may produce a passivated rare-earth material comprising the passivated layer.

[0245] The rare-earth material may comprise a lanthanide nitride powder, and the passivating gas may result in a thin lanthanide oxide layer on the surface of the lanthanide nitride powder. The remaining volume of the powder may still consist of the original lanthanide nitride material. Exposure to the passivating gas may produce a passivated lanthanide nitride material comprising the passivated layer. The passivated rare-earth material may comprise a passivated rare-earth nitride. The passivated layer of the rare-earth material may comprise a lanthanide oxide or a lanthanide oxynitride.

[0246] The passivated layer of the rare-earth material may comprise a depth of less than about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, or more, nanometers. The passivated layer of the rare-earth material may comprise a depth of less than about 5 nanometers. The passivated layer of the rare-earth material may comprise a depth of less than about 10 nanometers. The passivated layer may not spontaneously-28- WSGR Docket No. 68554-702.101ignite upon exposure to air. The passivated layer may not spontaneously ignite upon exposure to oxygenating compounds.Computer systems

[0247] The present disclosure provides computer systems that are programmed to implement methods of the disclosure. FIG. 5 shows a computer system 501 that is programmed or otherwise configured to facilitate production of NH3 synthesis catalysts. The computer system 501 can regulate various aspects of methods, systems, or compositions of the present disclosure, such as, for example, selecting a rare-earth material; selecting a support material; selecting an oxidant- free environment; selecting a passivating gas; selecting a grinding, milling, or crushing step; selecting a media; selecting amounts or concentrations of a rare-earth material, a support material, an oxidant-free environment over time, a media, a passivating gas, or a promoter; selecting a temperature ramp recipe; selecting a gradient rate for a passivating gas; selecting a promoter; measuring a depth of a passivated layer; or measuring a synthesis rate of an NH3 synthesis catalyst. The computer system 501 can be an electronic device of a user or a computer system that is remotely located with respect to the electronic device. The electronic device can be a mobile electronic device.

[0248] The computer system 501 includes a central processing unit (CPU, also “processor” and “computer processor” herein) 505, which can be a single core or multi core processor, or a plurality of processors for parallel processing. The computer system 501 also includes memory or memory location 510 (e.g., random-access memory, read-only memory, flash memory), electronic storage unit 515 (e.g., hard disk), communication interface 520 (e.g., network adapter) for communicating with one or more other systems, and peripheral devices 525, such as cache, other memory, data storage and / or electronic display adapters. The memory 510, storage unit 515, interface 520 and peripheral devices 525 are in communication with the CPU 505 through a communication bus (solid lines), such as a motherboard. The storage unit 515 can be a data storage unit (or data repository) for storing data. The computer system 501 can be operatively coupled to a computer network (“network”) 530 with the aid of the communication interface 520. The network 530 can be the Internet, an internet and / or extranet, or an intranet and / or extranet that is in communication with the Internet. The network 530 in some cases is a telecommunication and / or data network. The network 530 can include one or more computer servers, which can enable distributed computing, such as cloud computing. The network 530, in some cases with the aid of the computer system 501, can implement a peer-to-peer network, which may enable devices coupled to the computer system 501 to behave as a client or a server.

[0249] The CPU 505 can execute a sequence of machine-readable instructions, which can be embodied in a program or software. The instructions may be stored in a memory location, such as-29- WSGR Docket No. 68554-702.101the memory 510. The instructions can be directed to the CPU 505, which can subsequently program or otherwise configure the CPU 505 to implement methods of the present disclosure. Examples of operations performed by the CPU 505 can include fetch, decode, execute, and writeback.

[0250] The CPU 505 can be part of a circuit, such as an integrated circuit. One or more other components of the system 501 can be included in the circuit. In some cases, the circuit is an application specific integrated circuit (ASIC).

[0251] The storage unit 515 can store files, such as drivers, libraries and saved programs. The storage unit 515 can store user data, e.g., user preferences and user programs. The computer system 501 in some cases can include one or more additional data storage units that are external to the computer system 501, such as located on a remote server that is in communication with the computer system 501 through an intranet or the Internet.

[0252] The computer system 501 can communicate with one or more remote computer systems through the network 530. For instance, the computer system 501 can communicate with a remote computer system of a user. Examples of remote computer systems include personal computers (e.g., portable PC), slate or tablet PC’s (e.g., Apple® iPad, Samsung® Galaxy Tab), telephones, Smart phones (e.g., Apple® iPhone, Android-enabled device, Blackberry®), or personal digital assistants. The user can access the computer system 501 via the network 530.

[0253] Methods as described herein can be implemented by way of machine (e.g., computer processor) executable code stored on an electronic storage location of the computer system 501, such as, for example, on the memory 510 or electronic storage unit 515. The machine executable or machine readable code can be provided in the form of software. During use, the code can be executed by the processor 505. In some cases, the code can be retrieved from the storage unit 515 and stored on the memory 510 for ready access by the processor 505. In some situations, the electronic storage unit 515 can be precluded, and machine-executable instructions are stored on memory 510.

[0254] The code can be pre-compiled and configured for use with a machine having a processer adapted to execute the code or can be compiled during runtime. The code can be supplied in a programming language that can be selected to enable the code to execute in a pre-compiled or as- compiled fashion.

[0255] Aspects of the systems and methods provided herein, such as the computer system 501, can be embodied in programming. Various aspects of the technology may be thought of as “products” or “articles of manufacture” typically in the form of machine (or processor) executable code and / or associated data that is carried on or embodied in a type of machine readable medium. Machine-executable code can be stored on an electronic storage unit, such as-30- WSGR Docket No. 68554-702.101memory (e.g., read-only memory, random-access memory, flash memory) or a hard disk. “Storage” type media can include any or all of the tangible memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide non-transitory storage at any time for the software programming. All or portions of the software may at times be communicated through the Internet or various other telecommunication networks. Such communications, for example, may enable loading of the software from one computer or processor into another, for example, from a management server or host computer into the computer platform of an application server. Thus, another type of media that may bear the software elements includes optical, electrical and electromagnetic waves, such as used across physical interfaces between local devices, through wired and optical landline networks and over various air-links. The physical elements that carry such waves, such as wired or wireless links, optical links or the like, also may be considered as media bearing the software. As used herein, unless restricted to non-transitory, tangible “storage” media, terms such as computer or machine “readable medium” refer to any medium that participates in providing instructions to a processor for execution.

[0256] Hence, a machine readable medium, such as computer-executable code, may take many forms, including but not limited to, a tangible storage medium, a carrier wave medium or physical transmission medium. Non-volatile storage media include, for example, optical or magnetic disks, such as any of the storage devices in any computer(s) or the like, such as may be used to implement the databases, etc. shown in the drawings. Volatile storage media include dynamic memory, such as main memory of such a computer platform. Tangible transmission media include coaxial cables; copper wire and fiber optics, including the wires that comprise a bus within a computer system. Carrier-wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media therefore include for example: a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD or DVD-ROM, any other optical medium, punch cards paper tape, any other physical storage medium with patterns of holes, a RAM, a ROM, a PROM and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave transporting data or instructions, cables or links transporting such a carrier wave, or any other medium from which a computer may read programming code and / or data. Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.

[0257] The computer system 501 can include or be in communication with an electronic display 535 that may comprise a user interface (UI) 540 for providing, for example, options for selecting-31- WSGR Docket No. 68554-702.101a rare-earth material; selecting a support material; selecting an oxidant-free environment; selecting a passivating gas; selecting a grinding, milling, or crushing step; selecting a media; selecting amounts or concentrations of a rare-earth material, a support material, an oxidant-free environment over time, a media, a passivating gas, or a promoter; selecting a temperature ramp recipe; selecting a gradient rate for a passivating gas; selecting a promoter; measuring a depth of a passivated layer; or measuring a synthesis rate of an NH3 synthesis catalyst. Examples of UI’s include, without limitation, a graphical user interface (GUI) and web-based user interface.

[0258] Methods and systems of the present disclosure can be implemented by way of one or more algorithms. An algorithm can be implemented by way of software upon execution by the central processing unit 505. The algorithm can, for example, select a rare-earth material; select a support material; select an oxidant-free environment; select a passivating gas; select a grinding, milling, or crushing step; select a media; select amounts or concentrations of a rare-earth material, a support material, an oxidant-free environment over time, a media, a passivating gas, or a promoter; select a temperature ramp recipe; select a gradient rate for a passivating gas; select a promoter; measuring a depth of a passivated layer; or measuring a synthesis rate of an NH3 synthesis catalyst.Example 1: Improved Support and Reduced Sintering

[0259] The rare-earth materials disclosed herein may not leach from a support material when dispersed on the support material. A supported rare-earth material may not leach from the support material upon sonication in an ultrasonic bath for at least 15 minutes. The supported rare- earth material may not show a notable change of the morphology of the supported rare earth materials before and after being tested in NH3 synthesis reactor, as detected by scanning electron microscopy (SEM) and TEM. Similarly, the supported rare-earth material may not show a color change before and after being tested in NH3 synthesis reactor. Similarly, the supported rare-earth material may not show significant materials loss before and after being tested in NH3 synthesis reactor.

[0260] Simultaneous ball milling and nitriding may also limit sintering: there may be no notable change in the supported rare-earth catalysts before and after testing in the NH3 reactor, suggesting that sintering is rather limited when using supported rare-earth catalysts.Example 2: Improved Stability

[0261] The passivated layer of the rare-earth material may stabilize the composition for at least about 30 weeks. The passivated NH3 catalyst may be stable for at least about 30 weeks in a simple moisture control environment (e.g., less than 5% O2 exposure, around about 20 ± 2% atmospheric pressure, around about 17.5 ± 2.0°C atmospheric temperature). The passivated rare--32- WSGR Docket No. 68554-702.101earth material may be stable for at least about 30 weeks in a simple moisture control environment. Stability may be demonstrated by little to no structural degradation. Structural degradation may be analyzed via X-ray diffraction (XRD) data collected by a conventional omega-2theta scan within Bragg-Brentano conditions (FIG. 3B). XRD patterns of passivated rare-earth materials (a) immediately following the passivation process described herein and (b) 26 weeks following the passivation process show only peaks corresponding to the face-centered cubic lattice of rare-earth materials (FIG. 3B). The passivated layer of the rare-earth material protects the rare-earth material from reacting with the ambient atmosphere: no structural modification of the passivated rare-earth materials is observed over time. No diffracted signals from other phases are observed at 0 weeks or 26 weeks, and the XRD peak intensities of the crystallographic planes of the passivated rare-earth materials do not weaken significantly over time (FIG. 3B). Visual inspections of the passivated rare-earth materials show no change in color after exposure to air (FIG. 3D).

[0262] Stability may also be demonstrated by NE synthesis rates comparable to or better than as-fabricated or fresh NE synthesis catalysts, as-fabricated or fresh rare-earth materials, or as- fabricated or fresh lanthanide nitride materials.

[0263] A freshly fabricated passivated rare-earth material and a stored passivated rare-earth material are used to synthesize NEL at 400 °C and a pressure of 5 bar (g), a weight hourly space velocity of 36000 mL / g / hr, with a hydrogen to nitrogen (H2:N2) ratio of 3 : 1. The stored passivated rare-earth material is stored for at least 12 weeks in a simple moisture control environment. The NEL synthesis rate is normalized to the NEL synthesis rate of the freshly fabricated passivated rare-earth material.

[0264] At 400 °C and a pressure of 5 bar (g), a weight hourly space velocity of 36000 mL / g / hr, and a hydrogen to nitrogen (H2:N2) ratio of 3: 1, the stored passivated rare-earth material shows a similar or slightly higher NFL synthesis rate (pmol / g / hr) than the freshly fabricated passivated rare-earth material. The stored passivated rare-earth material shows an NFL synthesis rate (pmol / g / hr) 1.02 times higher than the NFL synthesis rate of the freshly fabricated passivated rare-earth material.Example 3: Improved Ammonia Synthesis

[0265] Combinations of rare-earth materials and support materials may achieve a higher synthesis rate of NFL. The supported rare-earth material may synthesize NIL at a higher rate than the combined synthesis rate of rare-earth material and support material used separately (e.g., when both the rare-earth material and the support material are included in the synthesis reaction without having been bonded).-33- WSGR Docket No. 68554-702.101

[0266] For example, an N F catalyst material comprising lanthanum nitride and a support material comprising iron may be used to form a supported NH3 synthesis catalyst using the methods described herein. FIG. 4 shows a chart depicting normalized NH3 synthesis rates (pmol / g / hr) for different NH3 synthesis catalysts. A pure iron catalyst (“Fe ca”), a pure lanthanide nitride catalyst (“LaN”), and an iron-supported lanthanide nitride catalyst (“Lao.sFeo.s”) are used to synthesize NH3 at either 350 °C or 400 °C and a pressure of 5 bar (g), a weight hourly space velocity of 36000 mL / g / hr, and a passivating gas with a hydrogen to nitrogen (H2:N2) ratio of 3 : 1. The NH3 synthesis rates are normalized to the NH3 synthesis rates of the iron-supported lanthanide nitride (“Lao.sFeo.s”) catalyst.

[0267] The iron may act as a metallic support for the lanthanum nitride dispersed nanoparticle material. The iron-supported lanthanum nitride may facilitate a higher NH3 synthesis rate. At either 350 °C or 400 °C and a pressure of 5 bar (g), a weight hourly space velocity of 36000 mL / g / hr, and a hydrogen to nitrogen (H2:N2) ratio of 3: 1, the iron-supported lanthanide nitride catalyst (“Lao.sFeo.s”) shows a higher NH3 synthesis rate (pmol / g / hr) than a pure iron (“Fe ca”) catalyst, a pure lanthanide nitride (“LaN”) catalyst, and the pure iron (“Fe ca”) catalyst and the pure lanthanide nitride (“LaN”) catalyst combined (“LaN+Fe”) (FIG. 4). The NH3 synthesis rates are normalized to the NH3 synthesis rates of the iron-supported lanthanide nitride catalyst.

[0268] The iron-supported lanthanide nitride catalyst (“Lao.sFeo.s”) shows an NH3 synthesis rate (pmol / g / hr) 11.2 times and 4.2 times higher than the NH3 synthesis rate of the pure iron (“Fe ca”) catalyst. The iron-supported lanthanide nitride catalyst (“Lao.sFeo.s”) shows an NH3 synthesis rate (pmol / g / hr) 5.6 times and 5 times higher than the NH3 synthesis rate of the pure lanthanide nitride (“LaN”) catalyst. The iron-supported lanthanide nitride catalyst (“Lao.sFeo.s”) shows an NH3 synthesis rate (pmol / g / hr) 3.8 times and 2.3 times higher than the combined (e.g., summed) NH3 synthesis rate of the pure lanthanide nitride catalyst and the pure iron catalyst (“LaN+Fe”).

[0269] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is therefore-34- WSGR Docket No. 68554-702.101contemplated that the invention shall also cover any such alternatives, modifications, variations, or equivalents. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.-35- WSGR Docket No. 68554-702.101

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A method comprising:(a) providing at least one rare-earth material in a chamber,(b) providing at least one support material in the chamber,(c) creating an oxidant-free environment in the chamber,(d) grinding, milling, or crushing the at least one rare-earth material and the at least one support material.

2. The method of claim 1, further comprising:(e) providing a passivating gas to the chamber, and(f) passivating a layer of the rare-earth material.

3. The method of any one of claim 1 or claim 2, wherein the oxidant-free environment is at a positive pressure, a negative pressure, or an atmospheric pressure.

4. The method of any one of claims 1-3, wherein (d) further comprises grinding, milling, or crushing by a mechanical process.

5. The method of any one of claims 1-4, wherein (d) further comprises grinding, milling, or crushing by a mechanochemical process.

6. The method of claim 5, wherein the mechanochemical process comprises a ball milling process.

7. The method of any one of claim 5 or claim 6, wherein the mechanochemical process comprises a disc milling process or a jaw crushing process.

8. The method of any one of claim 6 or claim 7, wherein the ball milling process comprises milling with a grinding jar, shaker mill, a mixer-type mill, a planetary mill, or a high- energy planetary mill.

9. The method of claim 8, wherein the grinding jar comprises steel, zirconium, zirconia, or tungsten carbide.

10. The method of any one of claim 8 or claim 9, wherein the grinding jar contains milling balls, wherein the milling balls comprise steel, zirconium, zirconia, or tungsten carbide.

11. The method of claim 10, wherein the milling balls comprise a diameter of at least about 0.1 mm to at least about 20 mm.

12. The method of any one of claims 1-11, wherein (d) further comprises producing a supported rare-earth material.

13. The method of claim 12, wherein the supported rare-earth material comprises a supported rare-earth nitride.-36- WSGR Docket No. 68554-702.10114. The method of any one of claim 12 or claim 13, wherein the supported rare-earth material comprises the at least one rare-earth material and the at least one support material, and wherein the at least one rare-earth material is located on or is in direct contact with the at least one support material in a catalyst layer.

15. The method of any one of claims 2-14, wherein the passivating gas comprises oxygen or moisture.

16. The method of any one of claims 2-15, wherein (e) further comprises providing the passivating gas at a gradient.

17. The method of any one of claims 2-16, wherein (f) comprises oxidizing the layer of the rare-earth material.

18. The method of any one of claims 2-17, wherein (f) further comprises producing a passivated layer of the rare-earth material at the exterior surface of the catalyst layer.

19. The method of claim 18, wherein the passivated layer of the rare-earth material comprises a depth of less than about 5 nanometers.

20. The method of any one of claim 18 or claim 19, wherein the passivated layer of the rare- earth material comprises a depth of less than about 10 nanometers.

21. The method of any one of claims 18-20, wherein the passivated layer of the rare-earth material comprises a lanthanide oxide or a lanthanide oxynitride.

22. The method of any one of claims 2-21, wherein (f) further comprises producing a passivated rare-earth material.

23. The method of any one of claims 2-22, wherein (f) further comprises producing a supported and passivated rare-earth material.

24. The method of any one of claim 22 or claim 23, wherein the passivated rare-earth material comprises a passivated rare-earth nitride.

25. The method of any one of claims 22-24, wherein the passivated rare-earth material is stable for at least 30 weeks.

26. The method of any one of claims 1-25, further comprising:(g) providing a promoter material to the chamber before (c).

27. The method of claim 26, wherein the promoter material comprises an alkali metal, alkaline earth metal, or a group 13 element.

28. The method of any one of claims 1-27, wherein the at least one rare-earth material comprises a rare-earth precursor or a rare-earth metal.

29. The method of any one of claims 1-28, wherein the at least one rare-earth material comprises a rare-earth nitride.-37- WSGR Docket No. 68554-702.10130. The method of any one of claims 1-29, wherein the at least one rare-earth material comprises a lanthanide.

31. The method of any one of claims 1-30, wherein the at least one rare-earth material comprises a lanthanide salt, a lanthanide halide, a lanthanide chalcogenide, or a lanthanide pnictide.

32. The method of any one of claims 1-31, wherein the at least one rare-earth material comprises a lanthanide oxide, a lanthanide hydride, a lanthanide hydroxide, a lanthanide chloride, a lanthanide amide, or a lanthanide iodide.

33. The method of any one of claims 1-32, wherein the rare-earth nitride comprises lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) ytterbium (Yb), or lutetium (Lu).

34. The method of any one of claims 1-33, wherein the at least one rare-earth nitride comprises a lanthanide alloy comprising at least two lanthanides selected from the group consisting of: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

35. The method of any one of claims 1-34, wherein the at least one rare-earth nitride comprises a lanthanide nitride.

36. The method of any one of claims 1-35, wherein the at least one rare-earth nitride comprises lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), or lutetium nitride (LuN).

37. The method of any one of claims 1-36, wherein the at least one rare-earth nitride comprises a lanthanide nitride alloy comprising at least two lanthanide nitrides selected from the group consisting of: lanthanum nitride (LaN), cerium nitride (CeN), praseodymium nitride (PrN), neodymium nitride (NdN), samarium nitride (SmN), europium nitride (EuN), gadolinium nitride (GdN), terbium nitride (TbN), dysprosium nitride (DyN), holmium nitride (HoN), erbium nitride (ErN), thulium nitride (TmN), ytterbium nitride (YbN), and lutetium nitride (LuN).

38. The method of any one of claims 1-37, wherein the at least one support material is a non- porous solid or a porous solid.-38- WSGR Docket No. 68554-702.10139. The method of any one of claims 1-38, wherein the at least one support material is porous, and wherein the at least one support material comprises a surface area from 1 square meter to 2,000 square meters per gram.

40. The method of any one of claims 1-39, wherein the at least one support material is catalytically active.

41. The method of any one of claims 1-40, wherein the at least one support material is catalytically passive.

42. The method of any one of claims 1-41, wherein the at least one support material comprises a diameter of at least about 5 nanometers to at least about 1 centimeter.

43. The method of any one of claims 1-42, wherein the at least one support material comprises a transition metal, a carbide, an oxide, a nitride, or a carbon allotrope.

44. The method of any one of claims 1-43, wherein the oxidant-free environment is (i) a vacuum, (ii) an inert atmosphere, (iii) an argon atmosphere, or (iv) a nitrogen atmosphere.

45. The method of claim 44, wherein the nitrogen atmosphere comprises molecular nitrogen N2 or a nitrogen species.

46. A system comprising:(a) a chamber that receives at least one rare-earth material and at least one support material,(b) a source of an oxidant-free atmosphere that creates an oxidant-free environment in the chamber,(c) a grinding, milling, or crushing apparatus that grinds, mills, or crushes the at least one rare-earth nitride and the at least one support material.

47. The system of claim 46, wherein the source of the oxidant-free atmosphere creates the oxidant-free environment at a positive pressure, a negative pressure, or an atmospheric pressure.

48. The system of any one of claim 46 or claim 47, wherein the chamber further receives a media that mills, grinds, or crushes the at least one rare-earth material and the at least one support material.

49. The system of any one of claims 46-48, further comprising:(d) a source of a passivating gas, wherein the passivating gas passivates a layer of the rare-earth material.

50. A method comprising:(a) providing at least one rare-earth material or a supported rare-earth material in a chamber,(c) creating an oxidant-free environment in the chamber,-39- WSGR Docket No. 68554-702.101(e) providing a passivating gas to the chamber, and(f) passivating a layer of the rare-earth material or the supported rare-earth material.

51. The method of claim 50, wherein (a) comprises providing the at least one rare-earth material in the chamber, and wherein the method further comprises:(b) providing at least one support material in the chamber after (a).

52. The method of claim 51, wherein (a) comprises providing the at least one rare-earth material in the chamber, and wherein the method further comprises:(d) grinding or milling or crushing the at least one rare-earth material and the at least one support material after (c).

53. A composition comprising at least one rare-earth material and at least one support material, wherein the at least one rare-earth material is located on or is in direct contact with the at least one support material in a catalyst layer, and wherein the at least one rare-earth material comprises a passivated layer at the exterior surface of the catalyst layer.

54. The composition of claim 53, wherein the passivated layer of the rare-earth material comprises a depth of less than about 10 nanometers.

55. The composition of any one of claim 53 or claim 54, wherein the passivated layer of the rare-earth material comprises a lanthanide oxide or a lanthanide oxynitride.

56. The composition of any one of claims 53-55, wherein the composition is stable for at least 30 weeks.-40- WSGR Docket No. 68554-702.101

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