Methods and catalyst compositions

Abstract

A process for producing a gaseous composition comprising hydrogen and a catalyst composition suitable for use in the process, wherein the process comprises contacting a feed gas composition comprising carbon monoxide and water with a catalyst composition comprising a copper species, an iron species and hydroxyapatite (HAP).

Description

Technical Field

[0001] This invention relates to a method for producing a composition containing hydrogen, wherein the method comprises contacting a feed gas composition containing carbon monoxide and water with a catalyst composition containing copper, iron, and hydroxyapatite (HAP). The method is particularly suitable for water-gas shift (WGS) reactions and can operate for extended periods within a temperature range at near-equilibrium carbon monoxide conversion levels. A method for preparing the catalyst composition is also provided. Background Technology

[0002] Hydrogen has proven its potential for use in transportation, energy storage, industrial processes, and heating due to its ability to address key challenges related to energy sustainability and decarbonization. Continued progress and innovation in Europe, Asia, and the United States have driven the growth of hydrogen use. The most common method for producing 95% of the world's hydrogen is steam methane reforming (SMR), where biomass, coal, or natural gas is reformed to produce hydrogen and carbon monoxide. This is typically followed by a water-gas shift (WGS) reaction to reduce carbon monoxide (CO) while increasing hydrogen production or adjusting the C-H ratio to suit downstream processes such as methanol synthesis or Fischer-Tropsch (FT) synthesis.

[0003] Given the importance of the WGS reaction in hydrogen production, developing highly active, selective, and stable catalysts for this process is crucial in both academia and industry. In industrial applications, the WGS reaction is typically carried out in two stages to maximize CO conversion. The first stage is chemically kinetic driven and involves a high-temperature WGS (HT-WGS) reactor operating at 310°C to 450°C, using an iron oxide / chromium-based catalyst to reduce the CO concentration to 1% to 5%. The second stage involves a low-temperature WGS (LT-WGS) reactor using a copper / zinc oxide catalyst, which is heated to 200°C to 250°C to further reduce the CO concentration to below 0.5%.

[0004] Commercial catalysts for low-temperature WGS reactions typically consist of 34% to 53% ZnO and 32% to 33% CuO, or 68% to 73% ZnO, 15% to 20% CuO, 9% to 14% Cr₂O₃, and 2% to 5% manganese, aluminum, and magnesium oxides. The copper crystals in these catalysts exhibit high activity (extremely low methanation) but are highly prone to sintering. These catalysts are also very temperature-sensitive, therefore low-temperature shift reactors are typically operated at 200°C to 250°C. Setting an upper temperature limit prevents copper particle agglomeration, while a lower limit helps reduce unwanted side reactions. For high-temperature WGS reactions, iron oxide / chromium-based catalysts typically consist of 90-95% Fe₂O₃ and 5-10% Cr₂O₃. In some cases, other compounds (e.g., CuO) are introduced to improve catalytic performance and structural stability. A significant problem with commercial iron catalysts is the presence of hexavalent chromium, which is harmful to human health and the environment due to its toxicity.

[0005] Although WGS is a mature technology in industry, commercially available WGS catalysts still have some drawbacks. For example, they are highly sensitive to oxygen due to their spontaneous combustion in air, and require a careful reduction step before activation. Furthermore, as mentioned above, Cu in Cu-Zn-Al catalysts is prone to sintering at high temperatures for LT WGS reactions. Due to the high toxicity of Cr, a key objective is to explore potential alternative elements to replace chromium as catalysts for HT WGS reactions. Therefore, many companies continue to invest in research and development to improve WGS catalysts. Noble metals such as Ru, Pt, and Pd have received considerable attention as active components in supported catalysts used in WGS reactions, but their high cost hinders their widespread industrial application.

[0006] There is a need in the art for stable catalysts suitable for LT and HT WGS reactions without the use of toxic compounds such as chromium. Summary of the Invention

[0007] In one aspect, this disclosure relates to a method for producing a gaseous composition containing hydrogen, wherein the method comprises contacting a feed gas composition containing carbon monoxide and water with a catalyst composition containing copper, iron and hydroxyapatite (HAP).

[0008] In another aspect, this disclosure relates to a method for preparing a catalyst composition, the method comprising mixing an aqueous solution of an iron salt or its hydrate and an aqueous solution of a copper salt or its hydrate with hydroxyapatite to provide a heterogeneous mixture.

[0009] In another respect, this disclosure relates to a catalyst composition obtained according to or achievable according to the methods described above.

[0010] In another respect, this disclosure relates to a catalyst composition comprising copper, iron and hydroxyapatite (HAP).

[0011] Preferred, applicable, and optional features of any particular aspect of the invention are also preferred, applicable, and optional features of other aspects. Attached Figure Description

[0012] Figure 1 XRD patterns of fresh catalyst compositions prepared by (A) wet impregnation (catalysts 1 to 4) and (B) coprecipitation (catalysts 5 to 8) were depicted.

[0013] Figure 2 The results of temperature screening tests on the synthesized catalyst composition in the water-gas shift reaction are shown.

[0014] Figure 3 A and Figure 3 B shows the change in CO conversion of catalyst 1 over time during a 360-hour stability test.

[0015] Figure 4 The CO conversion rate of catalyst 3 over time is shown in a 24-hour stability test conducted at 200°C, 300°C, 400°C, and 500°C.

[0016] Figure 5 XRD patterns of post-reaction deactivated catalyst compositions prepared by (A) wet impregnation (catalysts 1 to 4) and (B) coprecipitation (catalysts 5 to 8) were depicted.

[0017] Figure 6 XRD patterns of fresh, post-reaction deactivated, and post-stability test deactivated HAP samples (catalyst 3) loaded with Cu and Fe were depicted. Detailed Implementation

[0018] definition The terms used in this specification generally have their conventional meaning in the art, in the context of the subject matter, and in the specific context in which each term is used. Some terms are defined below to provide additional guidance in describing the compositions and methods of the disclosed subject matter and how to prepare and use said compositions and methods.

[0019] The term "about" means within an acceptable range of error for a particular value, as determined by a person of ordinary skill in the art, depending on how the value is measured or determined, i.e., the limitations of the measurement system. For example, according to practice in the art, "about" may mean within three or more standard deviations. Alternatively, "about" may mean a range of up to 20%, preferably up to 10%, more preferably up to 5%, and even more preferably up to 1% of a given value.

[0020] As used herein, the terms “comprising,” “including,” or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0021] In the detailed description herein, references to "implementation method," "one implementation method," "an implementation method," "in various implementation methods," etc., indicate that one or more implementation methods described may include specific features, structures, or characteristics, but each implementation method may not necessarily include the specific features, structures, or characteristics stated herein. Furthermore, such phrases do not necessarily refer to the same implementation method.

[0022] As used herein, the term "catalyst composition" includes both compositions containing catalytically active material and pre-catalyst compositions that typically require activation (e.g., by oxidation, reduction, and / or thermal treatment, or a combination thereof) to become catalytically active material. Suitablely, activation is carried out via reduction. The pre-catalyst composition may be converted to the catalytically active material in situ (i.e., under reaction conditions) (i.e., "activated"), or the pre-catalyst composition may be converted to the catalytically active material prior to use in the reaction (e.g., as a preliminary step).

[0023] As used herein, unless otherwise specified, the term "solid" means the physical form of a solid at standard ambient temperature and pressure (SATP), i.e., at a temperature of 298.15 K (25 °C) and a pressure of 100,000 Pa (1 bar, 14.5 psi, 0.9869 atm).

[0024] As used herein, unless otherwise specified, the term “gaseous” or “gas” means the gaseous physical form at standard ambient temperature and pressure (SATP), i.e., at a temperature of 298.15 K (25 °C) and a pressure of 100,000 Pa (1 bar, 14.5 psi, 0.9869 atm).

[0025] As used herein, the term "metallic substance" refers to any compound containing a metal. Therefore, unless otherwise specified, metallic substances include elemental metals, metal oxides, and other compounds containing metals, namely metal salts, alloys, hydroxides, carbides, and hydrides. When specific examples of metallic substances are described, the term includes all compounds containing that metal; for example, unless otherwise specified, iron substances include, for instance, elemental iron, iron oxides, iron salts, iron alloys, iron hydroxides, iron carbides, and iron hydrides. Similarly, chromium substances include all compounds containing chromium, such as chromium salts or their hydrates.

[0026] As used herein, the term "elemental metal" or specific examples thereof refers to a metal in its zero oxidation state.

[0027] Unless stated otherwise, the use of standard notation to indicate that an element refers to the element in any available oxidation state is intended to be in any available oxidation state. Similarly, the use of the term "metal" without further clarification is intended to be without limitation on the oxidation state other than those available oxidation states.

[0028] As used herein, the term "transition metal" refers to an element of one of three elemental series resulting from the filling of 3d, 4d, and 5d shells. Unless otherwise stated, when referring to a transition metal, either normally or using the standard notation for that particular transition metal, it means the element in any available oxidation state.

[0029] As used in this article, the term "syngas" (also known as syngas) is a fuel gas mixture that is essentially composed of hydrogen and carbon monoxide. However, small amounts of carbon dioxide and hydrocarbons may also be present.

[0030] As used herein, the term "molar ratio" refers to the proportion between the molar amounts of any two or more components contained in a composition, reaction, or product distribution. A molar ratio can be expressed as a single number, such as 3, or as 3:1, meaning the ratio of the first component to the second component is 3 to 1. In cases where there are more than two components, the molar ratio can be expressed as a series of proportions, such as 100:2:10:10, meaning the ratio of the first, second, third, and fourth components is 100:2:10:10.

[0031] Method for producing compositions containing hydrogen In one aspect, the present invention relates to a method for producing a composition containing hydrogen, wherein the method comprises contacting a feed gas composition containing carbon monoxide and water with a catalyst composition containing copper, iron and hydroxyapatite (HAP).

[0032] In one embodiment, the catalyst composition is loaded into the reaction zone. Optionally, the method includes a pre-step of activating the catalyst composition (e.g., by heating, and / or, if desired, by optional oxidation and subsequent reduction (e.g., with hydrogen or syngas)). Alternatively, the catalyst composition can be used directly in the reaction, where it is activated in situ, for example, under the reaction conditions.

[0033] In one embodiment, the method includes a pre-reduction step of the catalyst composition. In another embodiment, the method includes a pre-treatment step of treating the catalyst composition with a gaseous composition containing hydrogen (e.g., a mixture of nitrogen and hydrogen, suitably about 10% hydrogen in nitrogen). Suitably, the catalyst composition is treated with the gaseous composition containing hydrogen at a temperature of about 300 to about 500°C, more suitably about 400°C.

[0034] The catalyst composition can be used in a fixed bed, moving bed, or fluidized bed. Suitable for use in a fixed bed reactor. In one embodiment, the catalyst composition is packed in a fixed bed reactor, and the feed gas composition is fed through the bed. In some embodiments, the feed gas composition is continuously fed over the catalyst composition.

[0035] In one embodiment, a feed gas composition comprising carbon monoxide and water is contacted with a catalyst composition bed at an appropriate CO:H2O molar ratio and reacted under reaction conditions.

[0036] In one embodiment, the molar ratio of CO:H2O ranges from about 1:1 to about 1:10, suitably from about 1:1 to about 1:8, and more suitably from about 1:1 to about 1:7. In another embodiment, the molar ratio of CO:H2O ranges from about 1:5 to about 1:10, suitably from about 1:5 to about 1:9, and more suitably from about 1:5 to about 1:8.

[0037] In one embodiment, the molar ratio of CO:H2O ranges from about 1:1 to about 1:5, suitably from about 1:1 to about 1:4, more suitably from about 1:1 to about 1:3, and more suitably from about 1:1 to about 1:2.

[0038] In one embodiment, the feed gas composition may contain other gaseous components, such as carbon dioxide, syngas, and / or light gaseous hydrocarbons (such as methane). In one embodiment, the feed gas composition is derived from the product of another chemical process, such as steam reforming of methane.

[0039] In one embodiment, the reaction temperature is increased. As used herein, “increased temperature” is the temperature relative to the standard ambient temperature (i.e., a temperature of 298.15 K (25°C)). In one embodiment, the feed gas composition is contacted with the catalyst composition at a temperature of at least 100°C, suitably at least about 150°C, suitably at least about 200°C, suitably at least about 250°C, suitably at least about 300°C, suitably at least about 350°C, or suitably at least about 400°C.

[0040] In another embodiment, the feed gas composition is contacted with the catalyst composition at a temperature of about 100°C to about 500°C, suitably about 150°C to about 500°C, suitably about 200°C to about 500°C, or about 250°C to about 500°C, or about 300°C to about 500°C, or about 350°C to about 500°C, or about 400°C to about 500°C, or about 400°C to about 600°C, or about 400°C to about 550°C.

[0041] In another embodiment, the feed gas composition is contacted with the catalyst composition at a temperature of about 200°C to about 450°C, or about 200°C to about 400°C, or about 200°C to about 350°C, or about 200°C to about 300°C, or about 200°C to about 250°C.

[0042] The reaction pressure can be below atmospheric pressure, at atmospheric pressure, or elevated. In one embodiment, the reaction pressure can be atmospheric pressure or can be pressurized. As used herein, pressurization is an elevation relative to standard ambient pressure (i.e., 100,000 Pa (1 bar, 14.5 psi, 0.9869 atm)). In one embodiment, the feed gas composition is contacted with the catalyst composition at a pressure of about 100 kPa to about 10,000 kPa, or about 100 kPa to about 9,000 kPa, suitably about 100 kPa to about 8,000 kPa, suitably about 100 kPa to about 7,000 kPa, suitably about 100 kPa to about 6,000 kPa, or suitably about 100 kPa to about 5,000 kPa.

[0043] In another embodiment, the feed gas composition is contacted with the precatalyst composition or the catalyst composition at a pressure of about 100 kPa to about 3000 kPa, or about 100 kPa to about 2500 kPa, suitably about 100 kPa to about 2000 kPa.

[0044] In another embodiment, the feed gas composition is contacted with the precatalyst composition or the catalyst composition at a pressure of about 500 kPa to about 3000 kPa, or about 500 kPa to about 2500 kPa, suitably about 500 kPa to about 2000 kPa.

[0045] In another embodiment, the feed gas composition is contacted with the precatalyst composition or the catalyst composition at a pressure of about 1000 kPa to about 3000 kPa, or about 1000 kPa to about 2500 kPa, suitably about 1000 kPa to about 2000 kPa.

[0046] In another embodiment, the feed gas composition is contacted with the precatalyst composition or the catalyst composition at a pressure of about 100 kPa to about 1000 kPa, or about 100 kPa to about 500 kPa, suitably about 100 kPa to about 400 kPa, suitably about 100 kPa to about 300 kPa, suitably about 100 kPa to about 200 kPa, or suitably about 100 kPa to about 150 kPa.

[0047] In another embodiment, the feed gas composition is contacted with the catalyst composition at a pressure of about 0 kPa to about 100 kPa, or about 0 kPa to about 50 kPa.

[0048] In one implementation, from about 1 to about 20,000 h -1 Approximately 1,000 to approximately 10,000 h -1 Approximately 1000 to approximately 9000 h -1 Approximately 1000 to approximately 8000 h -1 Approximately 1000 to approximately 7000 h -1 Approximately 1000 to approximately 5000 h -1 Approximately 1000 to approximately 4000 h -1 The feed gas composition is brought into contact with the catalyst composition at a GHSV (gas hourly space velocity).

[0049] In another embodiment, at approximately 2000 to approximately 20,000 h -1 Approximately 2000 to approximately 10,000 h - 1. Suitable for approximately 2000 to 9000 hours. -1 Approximately 2000 to 8000 hours -1 Approximately 2000 to 7000 hours -1 Approximately 2000 to 5000 hours -1 Approximately 4000 h -1 The feed gas composition is brought into contact with the catalyst composition at a GHSV (gas hourly space velocity).

[0050] In this method, the contact duration between the catalyst composition and the feed gas composition can be varied. For example, embodiments in which the feed gas composition and the catalyst composition are contacted for a relatively long period of time are envisioned, thereby enabling the continuous production of hydrogen-containing compositions in a continuous manner.

[0051] For example, the feed gas composition can be contacted with the catalyst composition for at least 20 hours, suitably at least 50 hours, or suitably at least 100 hours under reaction conditions.

[0052] In one embodiment, the method produces a gaseous composition containing hydrogen. In one embodiment, the method produces a gaseous composition containing carbon dioxide in addition to hydrogen. In one embodiment, the method produces a gaseous composition containing both hydrogen and carbon dioxide.

[0053] Catalyst composition The catalyst composition comprises copper, iron, and hydroxyapatite (HAP). In one embodiment, the catalyst composition is substantially composed of copper, iron, and hydroxyapatite (HAP). In another embodiment, the catalyst composition comprises copper, iron, and hydroxyapatite (HAP).

[0054] In one embodiment, the copper material and the iron material are loaded onto the HAP.

[0055] In one embodiment, the copper component of the catalyst composition is present in an amount of at least about 15% by weight of the catalyst composition, suitably at least about 18% by weight of the catalyst composition, and more suitably at least about 20% by weight of the catalyst composition.

[0056] In one embodiment, the copper material of the catalyst composition is present in an amount of about 10% to about 40% by weight of the catalyst composition, suitably about 15% to about 40% by weight of the catalyst composition, suitably about 20% to about 40% by weight of the catalyst composition.

[0057] In one embodiment, the copper component of the catalyst composition is present in an amount of about 10% to about 30% by weight of the catalyst composition, suitably about 15% to about 30% by weight of the catalyst composition, suitably about 20% to about 30% by weight of the catalyst composition.

[0058] In one embodiment, the copper material of the catalyst composition is present in an amount of about 10% to about 25% by weight of the catalyst composition, suitably about 15% to about 25% by weight of the catalyst composition, suitably about 20% to about 25% by weight of the catalyst composition.

[0059] In one embodiment, the copper material is selected from elemental copper, copper oxides, copper alloys, copper hydroxides, and copper carbides. In one embodiment, the copper material is selected from elemental copper, copper oxides, and mixtures thereof. In one embodiment, the copper material is a copper oxide.

[0060] In one embodiment, the iron content of the catalyst composition is present in an amount of at least about 1% by weight of the catalyst composition, suitably at least about 3% by weight of the catalyst composition, and more suitably at least about 5% by weight of the catalyst composition.

[0061] In one embodiment, the iron content in the catalyst composition is present in an amount of about 1% to about 10% by weight of the catalyst composition, suitably about 1% to about 8% by weight of the catalyst composition, suitably about 1% to about 6% by weight of the catalyst composition.

[0062] In one embodiment, the iron content in the catalyst composition is present in an amount of about 3% to about 10% by weight of the catalyst composition, suitably about 3% to about 8% by weight of the catalyst composition, suitably about 3% to about 6% by weight of the catalyst composition, and suitably about 5% by weight of the catalyst composition.

[0063] In one embodiment, the iron substance is selected from elemental iron, iron oxides, iron alloys, iron hydroxides, and iron carbides. In one embodiment, the iron substance is selected from elemental iron, iron oxides, and mixtures thereof. In one embodiment, the iron substance is an iron oxide.

[0064] In one embodiment, the copper and iron substances are present in a molar ratio of about 5:1 to about 1:1, suitably about 5:1 to about 2:1, suitably about 5:1 to about 3:1, or suitably about 4:1.

[0065] In one embodiment, the catalyst composition comprises at least one additional metallic substance, such as an elemental metal or a metal oxide. In another embodiment, the catalyst composition comprises one or two additional metallic substances, such as an elemental metal or a metal oxide.

[0066] In one embodiment, the catalyst composition is substantially composed of copper, iron, other metallic substances, and hydroxyapatite (HAP).

[0067] Suitablely, the additional metallic substance is a transition metal, such as a noble metal. In one embodiment, the additional metallic substance is an elemental metal or a metal oxide.

[0068] In one embodiment, the additional metallic substance of the catalyst composition is present in an amount of at least about 0.05% by weight of the catalyst composition, suitably at least about 0.07% by weight of the catalyst composition, and more suitably at least about 0.1% by weight of the catalyst composition.

[0069] In one embodiment, the additional metallic substance of the catalyst composition is present in an amount of about 0.05% to about 1% by weight of the catalyst composition, suitably about 0.05% to about 0.7% by weight of the catalyst composition, suitably about 0.05% to about 0.5% by weight of the catalyst composition.

[0070] In one embodiment, the additional metallic substance in the catalyst composition is present in an amount of about 0.1 wt% to about 1 wt% of the catalyst composition, suitably about 0.1 wt% to about 0.7 wt% of the catalyst composition, suitably about 0.1 wt% to about 0.5 wt% of the catalyst composition, and suitably about 0.3 wt% of the catalyst composition.

[0071] In one embodiment, the catalyst composition comprises an additional metallic substance, suitably selected from noble metals. In one embodiment, the noble metal is suitably an elemental noble metal, a noble metal oxide, or a mixture thereof.

[0072] In one embodiment, the precious metal is selected from platinum, gold, and palladium.

[0073] In one embodiment, the catalyst composition comprises an additional transition metal material selected from cobalt, molybdenum, or nickel, such as elemental cobalt, elemental molybdenum, elemental nickel, their oxides, or combinations thereof.

[0074] In one embodiment, the catalyst composition is free of chromium.

[0075] Hydroxyapatite (HAP) is a substance with the formula Ca5(PO4)3(OH) (usually written as Ca 10 (PO4)6(OH)2 indicates a crystalline material whose crystal cell contains two solids. The most common HAP crystal structure is hexagonal, which has P63 / m space group symmetry, with lattice parameters a=b=9.432, c=6.881Å and γ=120°.

[0076] HAP can be synthesized from phosphate and calcium salts via various methods, including dry, wet, and thermal processes. In one embodiment, HAP can be obtained by or through a wet process (e.g., wet chemical precipitation).

[0077] In one embodiment, HAP is obtained by or through the following steps: mixing a phosphate, a calcium salt, and water to form a solution, heating the solution, and treating it with an alkali. In one embodiment, the phosphate is ammonium phosphate. In one embodiment, the calcium salt is calcium chloride. In one embodiment, the solution is heated to approximately 100°C. In one embodiment, the alkali is ammonium hydroxide, which is suitably added to adjust the pH to approximately 10 to 11.

[0078] In one implementation, the Ca / P ratio of the HAP is from about 1.6 to about 1.8, appropriately from about 1.667 to about 1.75.

[0079] In one embodiment, the catalyst composition has a specific surface area of ​​at least about 20 m². 2 / g, appropriately at least about 25 m 2 / g. Specific surface area can be measured according to techniques known in the art. For example, specific surface area can be determined, for example, by the equilibrium adsorption and desorption isotherms of nitrogen at -196°C, using the BET method.

[0080] In one embodiment, the catalyst composition has a specific surface area of ​​about 5 m². 2 / g to approximately 500 m 2 / g. For example, the specific surface area of ​​the catalyst composition can be about 5 m². 2 / g to approximately 400 m 2 / g. For example, the specific surface area of ​​the catalyst composition can be about 5 m². 2 / g to approximately 300 m 2 / g.

[0081] In one embodiment, the catalyst composition has a specific surface area of ​​about 20 m². 2 / g to approximately 300 m 2 / g. For example, the specific surface area of ​​the catalyst composition may be about 20 m². 2 / g to approximately 200 m 2 / g. For example, the specific surface area of ​​the catalyst composition may be about 20 m². 2 / g to approximately 100 m 2 / g.

[0082] In another embodiment, the catalyst composition has a specific surface area of ​​about 20 m². 2 / g to approximately 100 m 2 / g. For example, the specific surface area of ​​the catalyst composition may be about 20 m². 2 / g to approximately 50 m 2 / g. For example, the specific surface area of ​​the catalyst composition may be about 20 m². 2 / g to approximately 30 m 2 / g.

[0083] In one embodiment, the specific surface area is measured by determining the amount of adsorption on the sample, wherein the sample surface adsorbs molecules with a known adsorption occupancy area at the temperature of liquid nitrogen (-196°C, 77 K). In one embodiment, the specific surface area is measured at 77 K using isothermal N2 adsorption-desorption via the BET method (BET multi-point measurement). For example, the measurement can be performed using an automated specific surface area and pore distribution analyzer, such as the TriStar II 3020 (a product of McMurray Technology).

[0084] In one embodiment, the total pore volume of the catalyst composition is about 0.01 cm³. 3 / g or higher, appropriately about 0.02 cm 3 / g or higher, appropriately about 0.03 cm 3 / g or higher, appropriately about 0.04 cm 3 / g or higher, appropriately about 0.05 cm 3 / g or higher.

[0085] In another embodiment, the total pore volume of the catalyst composition is about 0.01 cm³. 3 / g to approximately 0.8cm 3 / g, appropriately about 0.01 cm 3 / g to approximately 0.7 cm 3 / g, appropriately about 0.01 cm 3 / g to approximately 0.5 cm 3 / g, appropriately about 0.01% to about 0.3 cm 3 / g, appropriately about 0.01 m 3 / g to approximately 0.1 cm 3 / g.

[0086] In another embodiment, the total pore volume of the catalyst composition is about 0.01 cm³. 3 / g to approximately 0.09cm 3 / g, appropriately about 0.02 cm 3 / g to approximately 0.09 cm 3 / g, appropriately about 0.025 cm 3 / g to approximately 0.09 cm 3 / g, appropriately about 0.03 cm 3 / g to approximately 0.09 cm 3 / g.

[0087] In another embodiment, the total pore volume of the catalyst composition is about 0.05 cm³. 3 / g to approximately 0.1cm 3 / g, appropriately about 0.06 cm 3 / g to approximately 0.1 cm 3 / g, appropriately about 0.07 cm 3 / g to approximately 0.1 cm 3 / g, appropriately about 0.08 cm 3 / g.

[0088] In one implementation, the total pore volume can be measured by isothermal N2 adsorption-desorption at 77 K, and the pore size distribution can be plotted using the desorption branch via the Barrett-Joyner-Halenda (BJH) method. Alternatively, the measurement can be performed using an automated specific surface area and pore distribution analyzer, such as the TriStar II 3020 (a product of McMurray Technology).

[0089] In one embodiment, the catalyst composition comprises copper or its oxide, iron or its oxide, and HAP, or is substantially composed of / from copper or its oxide, iron or its oxide, and HAP. Suitably, the Cu:Fe molar ratio is from about 5:1 to about 3:1, suitably about 4:1.

[0090] In one embodiment, the catalyst composition comprises at least about 18% by weight copper or its oxide, at least about 3% by weight iron or its oxide, and HAP, or is substantially composed of / consisting of at least about 18% by weight copper or its oxide, at least about 3% by weight iron or its oxide, and HAP. Suitably, the catalyst composition has a concentration of about 20 to about 30 μm. 3 Specific surface area per g and / or approximately 0.05 cm² 3 / g to approximately 0.1 cm 3 / g total pore volume.

[0091] In one embodiment, the catalyst composition comprises about 20% to about 25% by weight of copper or its oxide, about 5% to about 10% by weight of iron or its oxide, and HAP, or is substantially composed of / from about 20% to about 25% by weight of copper or its oxide, about 5% to about 10% by weight of iron or its oxide, and HAP. Suitably, the catalyst composition has a concentration of about 20 to about 30 μm. 2 Specific surface area per g and / or approximately 0.05 cm² 3 / g to approximately 0.1 cm 3 / g total pore volume.

[0092] In one embodiment, the catalyst composition is in the form of powder, pellets, granules, or shaped articles (e.g., a structured monolith or sculptured framework).

[0093] In one embodiment, the catalyst composition may also contain one or more binders, such as inorganic binders or natural gums.

[0094] Method for producing catalyst composition In one aspect, this disclosure relates to a method for preparing a catalyst composition, the method comprising mixing an aqueous solution of an iron salt or its hydrate and an aqueous solution of a copper salt or its hydrate with hydroxyapatite to provide a heterogeneous mixture.

[0095] Where appropriate, the heterogeneous mixture is stirred or agitated for at least about 10 minutes, and where appropriate, from about 10 minutes to 24 hours. Stirring or agitation is usually carried out at ambient temperature (i.e., from about 15°C to about 25°C).

[0096] In one embodiment, the method includes (i) mixing an aqueous solution of an iron salt or its hydrate and an aqueous solution of a copper salt or its hydrate with hydroxyapatite to provide a heterogeneous mixture, and (ii) removing the aqueous solvent to provide a solid.

[0097] In one embodiment, the aqueous solvent is removed under reduced pressure and / or increased temperature (e.g., from about 50°C to about 90°C). In another embodiment, rotary evaporation is used to remove the aqueous solvent.

[0098] In one embodiment, the method includes (i) mixing an aqueous solution of an iron salt or its hydrate and an aqueous solution of a copper salt or its hydrate with hydroxyapatite to provide a heterogeneous mixture; (ii) removing the aqueous solvent to provide a solid; and (iii) calcining the solid to provide a catalyst composition.

[0099] In one embodiment, the calcination is carried out at a temperature of about 400°C to about 1000°C, or about 400°C to about 700°C, or about 400°C to about 600°C, or about 500°C to about 700°C, or about 500°C to about 600°C.

[0100] Suitably, the calcination is carried out by heating the sample at a heating rate of about 3 to about 10°C per minute, suitably about 5°C per minute. Suitably, the sample is heated to a temperature of about 500°C, suitably up to about 550°C, suitably up to 600°C, suitably up to 650°C, suitably up to 700°C.

[0101] Suitablely, the calcination is carried out in air, preferably in still air. Typically, the calcination will result in the decomposition of organic components and the oxidation of metallic substances.

[0102] In one embodiment, the method includes a preparatory step for preparing HAP. In one embodiment, this preparatory step includes preparing HAP using a wet process, such as wet chemical precipitation.

[0103] In one embodiment, HAP is prepared by mixing a phosphate, a calcium salt, and water to form a solution, heating the solution, and treating it with an alkali. In one embodiment, the phosphate is ammonium phosphate. In one embodiment, the calcium salt is calcium chloride. In one embodiment, the solution is heated to approximately 100°C. In one embodiment, the alkali is ammonium hydroxide, which is suitably added to adjust the pH to approximately 10 to 11.

[0104] In another aspect, this disclosure relates to catalyst compositions obtained by or that can be obtained by the methods described above.

[0105] In another aspect, this disclosure relates to catalyst compositions as described herein.

[0106] The invention will now be further described by the following numbered items that are not part of the claims: 1. A method for producing a composition containing hydrogen, wherein the method comprises contacting a feed gas composition containing carbon monoxide and water with a catalyst composition containing a copper substance, an iron substance and hydroxyapatite (HAP).

[0107] 2. The method according to item 1, wherein the copper material and the iron material are loaded on the HAP.

[0108] 3. The method according to claim 1 or 2, wherein the copper substance in the catalyst composition is present in an amount of at least about 15% by weight of the catalyst composition, suitably at least about 18% by weight of the catalyst composition, more suitably at least about 20% by weight of the catalyst composition.

[0109] 4. The method according to any one of the preceding items, wherein the copper substance in the catalyst composition is present in an amount of about 10% to about 30% by weight of the catalyst composition, suitably about 15% to about 30% by weight of the catalyst composition, suitably about 20% to 30% by weight of the catalyst composition.

[0110] 5. The method according to any one of the preceding items, wherein the copper substance is selected from elemental copper, copper oxides, copper alloys, copper hydroxides, and copper carbides.

[0111] 6. The method according to any one of the preceding items, wherein the copper substance is selected from elemental copper, copper oxides and mixtures thereof.

[0112] 7. The method according to any one of the preceding items, wherein the iron substance in the catalyst composition is present in an amount of at least about 1% by weight of the catalyst composition, suitably at least about 3% by weight of the catalyst composition.

[0113] 8. The method according to any one of the preceding items, wherein the iron substance in the catalyst composition is present in an amount of about 3% to about 10% by weight of the catalyst composition, suitably about 3% to about 8% by weight of the catalyst composition, suitably about 3% to about 6% by weight of the catalyst composition.

[0114] 9. The method according to any one of the preceding items, wherein the iron substance is selected from elemental iron, iron oxides, iron alloys, iron hydroxides and iron carbides.

[0115] 10. The method according to any one of the preceding items, wherein the iron substance is selected from elemental iron, iron oxides and mixtures thereof.

[0116] 11. The method according to any one of the preceding items, wherein the copper substance and the iron substance are present in a molar ratio of about 5:1 to about 1:1, suitably about 5:1 to about 3:1.

[0117] 12. The method according to any one of the preceding items, wherein the catalyst composition comprises at least one additional metallic substance.

[0118] 13. The method according to any one of the preceding items, wherein the catalyst composition is substantially composed of copper, iron, other metallic substances and hydroxyapatite (HAP).

[0119] 14. The method according to item 12 or 13, wherein the additional metallic substance is a transition metal substance.

[0120] 15. The method according to any one of claims 12 to 14, wherein the additional metallic substance of the catalyst composition is present in an amount of at least about 0.05% by weight of the catalyst composition, suitably at least about 0.07% by weight of the catalyst composition, more suitably at least about 0.1% by weight of the catalyst composition.

[0121] 16. The method according to any one of claims 12 to 15, wherein the additional metallic substance of the catalyst composition is present in an amount of about 0.05% by weight to about 1% by weight of the catalyst composition, suitably about 0.05% by weight to about 0.7% by weight of the catalyst composition, suitably about 0.05% by weight to about 0.5% by weight of the catalyst composition.

[0122] 17. The method according to any one of items 1 to 11, wherein the catalyst composition comprises copper or its oxide, iron or its oxide and HAP.

[0123] 18. The method according to any one of the preceding items, wherein the HAP is obtained by or can be obtained by a wet process, such as wet chemical precipitation.

[0124] 19. The method according to any one of the preceding items, wherein the HAP is obtained by or can be obtained by: mixing phosphate, calcium salt and water to form a solution, heating the solution and treating it with an alkali.

[0125] 20. The method according to item 19, wherein the solution is heated to about 100°C and / or the base is added to adjust the pH to about 10 to about 11.

[0126] 21. The method according to any one of the preceding claims, wherein the specific surface area of ​​the catalyst composition is at least about 20 m². 2 / g, appropriately at least about 25 m 2 / g.

[0127] 22. The method according to any one of the preceding claims, wherein the specific surface area of ​​the catalyst composition is about 20 m². 2 / g to approximately 100 m 2 / g, approximately 20 m 2 / g to approximately 50 m 2 / g, approximately 20 m 2 / g to approximately 30 m 2 / g.

[0128] 23. The method according to any one of the preceding claims, wherein the total pore volume of the catalyst composition is about 0.01 cm³. 3 / g or higher, appropriately about 0.02 cm 3 / g or higher, appropriately about 0.03 cm 3 / g or higher, appropriately about 0.04 cm 3 / g or higher, appropriately about 0.05 cm 3 / g or higher.

[0129] 24. The method according to any one of the preceding claims, wherein the total pore volume of the catalyst composition is about 0.01 cm³. 3 / g to approximately 0.09 cm 3 / g, appropriately about 0.02 cm 3 / g to approximately 0.09 cm 3 / g, appropriately about 0.025 cm 3 / g to approximately 0.09 cm 3 / g, appropriately about 0.03 cm 3 / g to approximately 0.09 cm 3 / g.

[0130] 25. The method according to any one of the preceding items, wherein the catalyst composition is in the form of powder, pellets, granules or shaped articles.

[0131] 26. The method according to any one of the preceding items, wherein the method includes a pre-step of activating the catalyst composition.

[0132] 27. The method according to item 26, wherein the catalyst composition is activated by reduction.

[0133] 28. The method according to item 26 or 27, wherein the catalyst composition is activated by heating with a gaseous composition comprising hydrogen or syngas, suitably at a temperature of about 300 to about 500°C, more suitably about 400°C.

[0134] 29. The method according to any one of the preceding items, wherein the molar ratio of carbon monoxide to water in the feed gas composition is about 1:1 to about 1:10, suitably about 1:1 to about 1:9, more suitably about 1:1 to about 1:8.

[0135] 30. The method according to any one of the preceding items, wherein the feed gas composition is contacted with the catalyst composition at a temperature of at least about 100°C, suitably at least about 150°C, suitably at least about 200°C, suitably at least about 250°C, suitably at least about 300°C, suitably at least about 350°C, or suitably at least about 400°C.

[0136] 31. The method according to any one of the preceding items, wherein the feed gas composition is contacted with the catalyst composition at a temperature of about 100°C to about 500°C, suitably about 150°C to about 500°C, suitably about 200°C to about 500°C, or about 250°C to about 500°C, or about 300°C to about 500°C, or about 350°C to about 500°C, or about 400°C to about 500°C, or about 400°C to about 600°C, or about 400°C to about 550°C.

[0137] 32. The method according to any one of the preceding items, wherein the feed gas composition is contacted with the catalyst composition at a pressure of about 100 kPa to about 10,000 kPa, or about 100 kPa to about 9,000 kPa, suitably about 100 kPa to about 8,000 kPa, suitably about 100 kPa to about 7,000 kPa, suitably about 100 kPa to about 6,000 kPa, suitably about 100 kPa to about 5,000 kPa, suitably about 100 kPa to about 4,000 kPa.

[0138] 33. The method according to any one of the preceding items, wherein from about 1 to about 20,000 h -1 Approximately 1000 to approximately 10000 h -1 Approximately 1000 to approximately 8000 h -1 Approximately 1000 to approximately 7000 h -1 Approximately 1000 to approximately 5000 h -1 The feed gas composition is brought into contact with the catalyst composition at a GHSV (gas hourly space velocity).

[0139] 34. The method according to any one of the preceding items, wherein the prepared composition is a gaseous composition.

[0140] 35. A method for preparing a catalyst composition, comprising mixing an aqueous solution of an iron salt or its hydrate and an aqueous solution of a copper salt or its hydrate with hydroxyapatite to provide a heterogeneous mixture.

[0141] 36. The method according to item 35, wherein the heterogeneous mixture is stirred or agitated for at least about 10 minutes, suitably from about 10 minutes to 24 hours.

[0142] 37. The method according to item 36, wherein the stirring or agitation is typically performed at ambient temperature, i.e., from about 15°C to about 25°C.

[0143] 38. The method according to any one of claims 35 to 37, wherein the method further comprises removing the aqueous solvent to provide a solid.

[0144] 39. The method of claim 38, wherein the method further comprises calcining the solid to provide the catalyst composition.

[0145] 40. The method according to claim 39, wherein the calcination is carried out at a temperature of about 400°C to about 1000°C, or about 400°C to about 700°C, or about 400°C to about 600°C, or about 500°C to about 700°C, or about 500°C to about 600°C.

[0146] 41. The method according to any one of items 35 to 40, comprising a preliminary step for preparing HAP, wherein a wet process, such as wet chemical precipitation, is suitably used to prepare HAP.

[0147] 42. The method according to item 41, wherein the HAP is prepared by mixing phosphate, calcium salt and water to form a solution, heating the solution and treating it with an alkali.

[0148] 43. The method according to item 42, wherein the solution is heated to about 100°C and / or an alkali is added to adjust the pH to about 10 to about 11.

[0149] 44. A catalyst composition obtained or available by any one of claims 35 to 43.

[0150] 45. A catalyst composition comprising a copper substance, an iron substance and hydroxyapatite (HAP).

[0151] 46. ​​The catalyst composition according to claim 45, wherein the copper material and the iron material are supported on the HAP.

[0152] 47. The catalyst composition according to item 45 or 46, wherein the copper substance of the catalyst composition is present in an amount of at least about 15% by weight of the catalyst composition, suitably at least about 18% by weight of the catalyst composition, more suitably at least about 20% by weight of the catalyst composition.

[0153] 48. The catalyst composition according to any one of claims 45 to 47, wherein the copper substance of the catalyst composition is present in an amount of about 10% to about 30% by weight of the catalyst composition, suitably about 15% to about 30% by weight of the catalyst composition, suitably about 20% to 30% by weight of the catalyst composition.

[0154] 49. The catalyst composition according to any one of claims 45 to 48, wherein the copper substance is selected from elemental copper, copper oxides, copper alloys, copper hydroxides, and copper carbides.

[0155] 50. The catalyst composition according to any one of items 45 to 49, wherein the copper substance is selected from elemental copper, copper oxides and mixtures thereof.

[0156] 51. The catalyst composition according to any one of claims 45 to 50, wherein the iron content of the catalyst composition is present in an amount of at least about 1% by weight of the catalyst composition, suitably at least about 3% by weight of the catalyst composition.

[0157] 52. The catalyst composition according to any one of claims 45 to 51, wherein the iron content of the catalyst composition is present in an amount of about 3% to about 10% by weight of the catalyst composition, suitably about 3% to about 8% by weight of the catalyst composition, suitably about 3% to about 6% by weight of the catalyst composition.

[0158] 53. The catalyst composition according to any one of claims 45 to 52, wherein the iron substance is selected from elemental iron, iron oxides, iron alloys, iron hydroxides, and iron carbides.

[0159] 54. The catalyst composition according to any one of items 45 to 53, wherein the iron substance is selected from elemental iron, iron oxides and mixtures thereof.

[0160] 55. The catalyst composition according to any one of claims 45 to 54, wherein the copper substance and the iron substance are present in a molar ratio of about 5:1 to about 1:1, suitably about 5:1 to about 3:1.

[0161] 56. The catalyst composition according to any one of claims 45 to 55, wherein the catalyst composition comprises at least one additional metallic substance.

[0162] 57. The catalyst composition according to any one of claims 45 to 56, wherein the catalyst composition is substantially composed of a copper substance, an iron substance, another metallic substance and hydroxyapatite (HAP).

[0163] 58. The catalyst composition according to item 56 or 57, wherein the additional metallic substance is a transition metal substance.

[0164] 59. The catalyst composition according to any one of claims 56 to 58, wherein the additional metallic substance of the catalyst composition is present in an amount of at least about 0.05% by weight of the catalyst composition, suitably at least about 0.07% by weight of the catalyst composition, more suitably at least about 0.1% by weight of the catalyst composition.

[0165] 60. The catalyst composition according to any one of claims 56 to 59, wherein the additional metallic substance of the catalyst composition is present in an amount of about 0.05% by weight to about 1% by weight, suitably about 0.05% by weight to about 0.7% by weight, suitably about 0.05% by weight to about 0.5% by weight.

[0166] 61. The catalyst composition according to any one of claims 45 to 55, wherein the catalyst composition comprises copper or its oxide, iron or its oxide, and HAP.

[0167] 62. The catalyst composition according to any one of items 45 to 61, wherein the HAP is obtained by or can be obtained by a wet process, such as wet chemical precipitation.

[0168] 63. The catalyst composition according to any one of items 45 to 62, wherein the HAP is obtained by or can be obtained by mixing a phosphate, a calcium salt and water to form a solution, heating the solution and treating it with an alkali.

[0169] 64. The catalyst composition according to claim 63, wherein the solution is heated to about 100°C and / or the base is added to adjust the pH to about 10 to about 11.

[0170] 65. The catalyst composition according to any one of claims 45 to 64, wherein the specific surface area of ​​said catalyst composition is at least about 20 m². 2 / g, appropriately at least about 25 m 2 / g.

[0171] 66. The catalyst composition according to any one of claims 45 to 65, wherein the specific surface area of ​​the catalyst composition is about 20 m². 2 / g to approximately 100 m 2 / g, Approximately 20 m 2 / g to approximately 50 m 2 / g, approximately 20 m 2 / g to approximately 30m 2 / g.

[0172] 67. The catalyst composition according to any one of claims 45 to 66, wherein the total pore volume of the catalyst composition is about 0.01 cm³. 3 / g or higher, appropriately about 0.02 cm 3 / g or higher, appropriately about 0.03 cm 3 / g or higher, appropriately about 0.04 cm 3 / g or higher, appropriately about 0.05 cm 3 / g or higher.

[0173] 68. The catalyst composition according to any one of claims 45 to 67, wherein the total pore volume of the catalyst composition is about 0.01 cm³. 3 / g to approximately 0.09 cm 3 / g, appropriately about 0.02 cm 3 / g to approximately 0.09 cm 3 / g, appropriately about 0.025 cm 3 / g to approximately 0.09 cm 3 / g, appropriately about 0.03 cm 3 / g to approximately 0.09 cm 3 / g.

[0174] 69. The catalyst composition according to any one of claims 45 to 68, wherein the catalyst composition is in the form of powder, pellets, granules or molded articles.

[0175] 70. The catalyst composition according to any one of items 45 to 69, wherein the catalyst composition is used for the production of hydrogen.

[0176] 71. The catalyst composition according to any one of claims 45 to 70, wherein the catalyst composition is used to react carbon monoxide with water.

[0177] 72. The catalyst composition according to any one of items 45 to 71, wherein the catalyst composition is used for catalyzing a water-gas shift reaction.

[0178] 73. The catalyst composition according to any one of items 45 to 72, wherein the catalyst composition does not contain chromium.

[0179] Example 1. Preparation of the catalyst composition 1.1 Synthesis of HAP catalysts supported on copper and HAP catalysts supported on copper and iron Hydroxyapatite (HAP) was synthesized via a precipitation method involving 300 mL of a 0.1 M ammonium phosphate ((NH4)2HPO4, Sigma-Aldrich, >98%) solution and 500 mL of a 0.1 M calcium chloride (CaCl2•2H2O, Sigma-Aldrich, >99%) solution. Initially, the ammonium phosphate solution was heated to 100 °C and refluxed for 30 minutes. Subsequently, the calcium chloride solution was added dropwise, followed by the addition of a 25% ammonium hydroxide solution (Alfa Aesar). This process resulted in the formation of a white suspension at pH 10.5, which was aged for 24 hours. After cooling to room temperature, the mixture was vacuum filtered and washed until a neutral pH was reached. The resulting gel was dried in an oven at 100 °C for 24 hours and then calcined in air at 550 °C for 2 hours.

[0180] Subsequently, Cu or Cu and Fe were loaded onto the surface of the synthesized HAP via a wet impregnation method. Appropriate amounts of Cu precursor (Cu(NO3)2, Sigma-Aldrich, >99.9%) and Fe precursor (Fe(NO3)3, Sigma-Aldrich, >98%) were dissolved in water and added to the HAP powder to achieve a nominal Cu content of 20 wt% and a nominal Fe content of 5 wt% in the synthesized catalyst. The heterogeneous mixture was stirred for 1 hour, followed by solvent evaporation at 50 °C under reduced pressure using a rotary evaporator to ensure good dispersion of the metal phase. The sample was then dried at 80 °C for 12 hours and calcined at 550 °C for 2 hours. These samples were labeled Catalyst 1 (Cu-loaded HAP) and Catalyst 3 (Cu and Fe-loaded HAP).

[0181] 1.2 Synthesis of Cu-containing catalyst compositions and CuFe-containing catalyst compositions Cu HAP catalysts were prepared via coprecipitation by heating 300 mL of a 0.1 M ammonium phosphate solution under reflux and stirring. Subsequently, 250 mL of a 0.1 M calcium chloride aqueous solution and 250 mL of a 0.1 M copper nitrate solution were mixed and added dropwise to the ammonium phosphate solution under vigorous stirring at 100 °C. The pH of the mixture was maintained at approximately 10.5 using a 25% ammonium hydroxide solution. The mixture was stirred vigorously at 100 °C and then aged at room temperature for 24 hours. The resulting suspension was filtered, washed with distilled water, dried at 80 °C for 24 hours, and then calcined in air at 550 °C for 2 hours. Cu, Fe HAP catalysts were prepared using similar steps using 300 mL of a 0.1 M ammonium phosphate solution, 250 mL of a 0.1 M calcium chloride solution, 125 mL of a 0.1 M copper nitrate solution, and 125 mL of a 0.1 M ferric nitrate solution to achieve ¼ Ca substitution by Cu and ¼ calcium substitution by Fe. These samples were labeled as catalyst 5 (Cu HAP) and catalyst 7 (Cu, Fe HAP).

[0182] 1.3 Preparation of catalyst compositions also containing Pt The catalyst compositions also contain Pt, which is introduced via a wet impregnation method. Catalysts 1, 3, 5, and 7 were impregnated with an aqueous solution of H₂PtCl₆ (Sigma-Aldrich, >37.50% Pt-based) to achieve a nominal Pt loading of 1 wt%. After stirring the mixture for 1 hour, the solvent was removed under reduced pressure using a rotary evaporator at 50 °C. The resulting precursors were then dried at 80 °C for 24 hours, followed by calcination in air at 550 °C for 2 hours. These catalysts are designated as Catalysts 2, 4, 6, and 8, as shown in Table 1 below.

[0183] 2. Catalytic performance In the automated catalytic miniature device Microactivity-Reference© designed by PID Eng&Tech, a fixed-bed reactor (bed volume: 1.5 cm³) made of steel (Hastelloy C276) is used. 3 The water-gas shift (WGS) reaction was carried out. The prepared catalyst composition was pre-reduced at 400°C for 1 hour, followed by heating at a rate of 10°C / min with a N2 mixture containing 10% H2 at a flow rate of 100 ml / min. The outlet gas was analyzed using a gas chromatograph (CP4900 microGC, Varian). The reaction gas mixture contained 4.5% CO and 30% H2O, with the remainder being nitrogen. The reaction was carried out over 4000 h. -1 The GHSV was operated at atmospheric pressure (1 bar) and a total flow rate of 100 ml / min.

[0184] The stability of Cu- and Fe-supported HAP catalysts was tested for 24 hours at 200℃, 300℃, 400℃, and 500℃ under the same pressure and atmosphere. During the heating phase, the feed gas was switched to N2 until the temperature stabilized, and then the gas was switched back to the reactant gas.

[0185] 3. Characterization of fresh and deactivated catalyst compositions The structural properties of the catalyst were evaluated using N2 adsorption-desorption isotherms recorded on a Micrometrics TriStar II 3020 instrument at the boiling point of nitrogen (-196 °C). Prior to these measurements, the samples were degassed under high vacuum at 250 °C for 2 hours. Specific surface area was determined by the Brunauer–Emmett–Teller (BET) method, and total pore volume was measured at a relative pressure (P / P0) of 0.97.

[0186] X-ray diffraction (XRD) analysis was performed on both fresh and used samples. XRD measurements were conducted at 40 mA and 45 kV using an X'Pert Pro PANalytic instrument equipped with Cu-Kα radiation (λ = 0.154 nm). Diffraction patterns were recorded in the range of 10 to 80° with a step size of 0.05° and a step time of 300 seconds.

[0187] The contents of Cu, Fe, and Pt were quantitatively analyzed using an iCAP 7200 ICP-OES Duo spectrometer (Thermo Fisher Scientific) via inductively coupled plasma mass spectrometry (ICP-MS). Prior to this analysis, the samples were microwave digested on the ETHOS EASY microwave digestion platform (Milestone).

[0188] 4. Results and Discussion 4.1 XRD Figure 1 XRD patterns (A) of catalyst compositions 1 to 4 prepared by wet impregnation and XRD patterns (B) of fresh samples of catalysts 5 to 8 prepared by coprecipitation are depicted. For the fresh samples, the observed peaks can be divided into two categories. The peaks at 35.8° and 39° belonging to the CuO phase (JCPDS 04-008-8209) [2] are at 35.8° and 39°. Figure 1 Peaks marked with red squares are shown in the image. All peaks marked with blue dots are attributed to HAP (JCPDS no. 09-0432) [1,2,5]. No peaks corresponding to Fe or Pt were observed.

[0189] As shown, the catalyst compositions (catalysts 1 to 4) prepared by the impregnation method exhibit a distinct CuO peak, which can be attributed to the oxidation of the copper precursor during the calcination step at 550 °C. No Fe or Pt peaks were detected, likely due to the low content and high dispersibility of these elements. Furthermore, all samples prepared by the impregnation method showed a well-defined HAP structure, indicating that the HAP structure was well maintained after the subsequent rotary evaporation step.

[0190] In contrast, for the catalyst compositions prepared by co-precipitation (catalysts 5 to 8), the HAP peak was significantly reduced in the iron-containing samples, indicating that the presence of iron significantly hindered the growth of the HAP structure. On the other hand, the addition of Cu in the co-precipitation method had minimal structural impact on the appearance of the HAP. However, unlike the copper samples synthesized by impregnation, no copper peak was detected in XRD, which may be due to the low concentration and high dispersibility of copper in the co-precipitated catalysts. ICP testing was performed to verify the elemental content.

[0191] 4.2 ICP To further understand the content of each active metal on the catalyst, the contents of Cu, Fe, and Pt were quantitatively analyzed by inductively coupled plasma mass spectrometry (ICP-MS) using an iCAP 7200 ICP-OES Duo spectrometer. The results are presented in Table 1.

[0192] Table 1. Cu, Fe, and Pt content of the catalyst composition

[0193] The results showed that different synthesis methods led to significant differences in elemental content. For samples synthesized using the impregnation method, the Cu content was approximately 20 wt%, with slight variations between samples. The Fe content in the iron-containing catalyst synthesized via the impregnation method was 5 wt% ± 0.2 wt%. In the initial design of the impregnation method, the amounts of copper nitrate and ferrous nitrite precursors were calculated to achieve 20 wt% Cu and 5 wt% Fe. ICP results confirmed the successful deposition of the active metal. For the Pt-containing sample synthesized via the impregnation method, the Pt content was 0.3 wt%.

[0194] For the sample synthesized using the coprecipitation method, the Cu content was only about 5% by weight, approximately one-quarter of that in the catalyst synthesized by the impregnation method. This explains why the Cu peak disappeared in the XRD of the coprecipitated sample due to the low content. In the initial catalyst synthesis design, equimolar amounts of Ca and Cu precursors were added to the synthesis with the goal of replacing half of the Ca in the HAP structure with Cu. However, no new peaks were detected in the XRD analysis, indicating that Cu was not successfully introduced into the HAP structure. ICP test results also showed that the Cu content in the Cu HAP catalyst was very low, indicating that most of the Cu was washed away during the filtration and distilled water washing steps. In contrast, the Fe content in Cu, Fe HAP (catalyst 7) ​​and Pt, Cu, Fe HAP (catalyst 8) was almost doubled. Compared to the Pt content in the Pt-supported HAP (catalyst 2) and the Pt, Cu, Fe-supported HAP (catalyst 4), the Pt concentration in the coprecipitated sample was only 0.18% by weight.

[0195] Although no corresponding peaks were observed in the XRD results, the presence of Fe and Pt in the catalyst was confirmed by the Fe and Pt content values ​​obtained from ICP testing. This may be because Fe and Pt are highly dispersed at the atomic level, thus preventing the formation of detectable crystal diffraction peaks in XRD, or because their particle size is smaller than the detection limit (4 nm).

[0196] 4.3 Texture Characteristics As described above, the BET surface area and pore volume of the catalyst composition were evaluated, and the results are summarized in Table 2 below.

[0197] Table 2. Texture characteristics of the catalyst composition

[0198] a. Calculated using the BET equation.

[0199] b. Pore volume calculated from N2 desorption at a relative pressure of 0.96.

[0200] As can be seen from Table 2, the BET surface area and pore volume are roughly proportional to each other. The BET surface areas of Cu HAP (catalyst 5), Pt, Cu HAP (catalyst 6), and Pt, Cu, Fe HAP (catalyst 8) are more than three times that of Cu-loaded HAP (catalyst 1), Cu and Fe-loaded HAP (catalyst 3), Pt and Cu-loaded HAP (catalyst 2), and Pt, Cu, Fe-loaded HAP (catalyst 4), indicating that co-precipitation results in a higher surface area than impregnation. A similar trend was observed for pore volume values. This may be because the pores of the HAP are blocked by the added active metal during the impregnation step.

[0201] However, compared with the corresponding catalysts (Cu HAP (catalyst 5) and Cu, Fe HAP (catalyst 7)) synthesized by coprecipitation, Cu-supported HAP (catalyst 1) and Cu, Fe-supported HAP (catalyst 3) exhibit better catalytic performance for the WGS reaction.

[0202] 4.4 Catalytic Activity Figure 2 The CO conversion rates for the WGS reaction of all studied catalyst compositions are shown. CO conversion increases with increasing temperature. Overall, the catalysts synthesized by the impregnation method exhibit better catalytic performance, with significantly higher CO conversion rates (catalysts 1 to 4). This performance can be attributed to the higher copper content in the catalysts prepared by the impregnation method, as described in the previous ICP section. All samples prepared by the impregnation method contained more than 20 wt% Cu, while the samples prepared by the co-precipitation method contained less than 7 wt% Cu. Since Cu is the predominant active phase in low-temperature WGS reactions, its content plays a crucial role in catalytic activity.

[0203] It is also noteworthy that, compared to the Cu-supported HAP (catalyst 1), the Cu- and Fe-supported HAP (catalyst 3) initially exhibited lower catalytic activity. However, when the temperature reached 300 °C, the catalytic activity of the Cu- and Fe-supported HAP (catalyst 3) began to approach that of catalyst 1, and became identical at 350 °C. Since Fe is a commonly used active metal in high-temperature WGS reactions within the appropriate temperature range of 310 °C to 450 °C, the lower catalytic activity of the Cu- and Fe-supported catalyst (catalyst 3) at lower temperatures may be due to the coexistence of Fe and Cu, which may hinder Cu's ability to activate the WGS reaction. However, once the temperature reaches the optimal range for iron, iron begins to function effectively.

[0204] Another finding is that Pt is detrimental to the WGS reaction in this case. Based on the catalytic behavior of the Pt- and Cu-supported HAP (catalyst 2), it is clear that the addition of Pt significantly reduces CO conversion activity. However, for the Pt-, Cu-, and Fe-supported HAP (catalyst 4), despite poor initial performance, the CO catalytic activity increases rapidly once the temperature enters the appropriate range for Fe, which again supports our previous hypothesis.

[0205] 4.5 Stability Test 4.5.1 Stability test of catalyst 1 (Cu-supported HAP) Because the Cu-supported HAP (catalyst 1) exhibited the best catalytic performance in CO conversion during temperature screening tests, it was selected for 360-hour stability testing in WGS. WGS was conducted at 300°C with a total feed flow rate of 100 ml / min (30 vol% H₂O + 4.5 vol% CO, balance N₂), 1 bar, and GHSV for 4000 h⁻¹. -1 Bed volume: 1.5cm 3 In this long-term stability test, oxidation start-up and shutdown cycles were performed at 1-hour intervals after 170 hours and 260 hours.

[0206] like Figure 3 As shown in Figure A, performance declined during the first 200 hours and then stabilized. After the initial 170 hours, CO conversion dropped to 25%. During the second 90-hour test phase following the oxidation start-up and shutdown cycles, CO conversion decreased to approximately 14%. After the second oxidation start-up and shutdown cycle, CO conversion increased slightly to 15% (see Figure A). Figure 3 B). These results indicate that the catalytic performance of Cu-supported HAP (catalyst 1) stabilizes after approximately 200 hours of operation. Once this stable state is reached, subsequent start-up and shutdown cycles have no further impact on performance.

[0207] 4.5.2 Stability test of catalyst 3 (HAP supported on Cu and Fe) Based on previous stability test results of Cu-supported HAP (catalyst 1), a significant performance degradation was observed in the first 100 hours. Since Cu- and Fe-supported HAP (catalyst 3) exhibited good CO activity at high temperatures (above 300°C), this sample was selected for stability testing at 200°C, 300°C, 400°C, and 500°C, held at each temperature for 24 hours, resulting in a total stability test duration of 96 hours. WGS was performed with a total feed flow rate of 100 ml / min (30 vol% H₂O + 4.5 vol% CO, balance N₂), 1 bar, and GHSV: 4000 h⁻¹. -1Bed volume: 1.5 cm 3 The results are shown in Figure 4 middle.

[0208] Catalyst 3 initially exhibited a CO conversion of 18.42% at 200 °C, which increased to 97.89% after 20 hours of testing. Similar trends were observed during stability tests at 300 °C, 400 °C, and 500 °C. Specifically, the CO conversion increased from 45.51% to 97.06% at 300 °C, from 56.95% to 95.81% at 400 °C, and from 91.62% to 95.67% at 500 °C.

[0209] Under the same conditions as in laboratory tests, the equilibrium CO conversion at 200 °C, 300 °C, 400 °C, and 500 °C was determined using Aspen HYSYS. The relevant data, along with the test results used for comparison, are provided in Table 3. First, it is noteworthy that the equilibrium CO conversion decreases with increasing temperature, which is thermodynamically expected based on the Le Chatelier principle. Since the WGS reaction is exothermic, it thermodynamically tends towards lower temperatures, thus producing higher equilibrium CO conversions at lower temperatures. This trend is consistent with the results observed in our laboratory tests. Furthermore, the CO conversion observed in laboratory tests at different temperatures approaches the equilibrium conversion after 24 hours of testing.

[0210] Table 3. Comparison of equilibrium conversion rates and test results at 200℃, 300℃, 400℃, and 500℃

[0211] Compared to the Cu-loaded HAP (catalyst 1), which showed a significant performance decline in the first 100 hours, the Cu- and Fe-loaded HAP (catalyst 3) exhibited higher stability, with CO conversion increasing to over 95%.

[0212] Although the same sample was used for stability tests at different temperatures, there were several intervals between the temperature transitions. During these intervals, N2 replaced the feed gas (H2O and CO) as it flowed through the reactor. This explains why the CO conversion rate dropped to a lower value during the tests and required time to recover. The catalyst surface may need time to resaturate reactant molecules, allowing them to adsorb onto the catalyst surface and occupy active sites, resulting in a gradual increase in CO conversion. In industrial applications, 24 hours is a very short period for the catalyst to reach its optimal activation state throughout the entire operating period, and therefore is unlikely to hinder its application.

[0213] Overall, the HAP (catalyst 3) supported on Cu and Fe exhibited near-equilibrium CO activity for both low-temperature (below 300℃) and high-temperature (above 350℃) WGS reactions, and showed stable CO activity during the 96-hour test.

[0214] 4.6 Post-reaction characterization Figure 5 The XRD patterns of the catalyst composition after WGS reaction are shown. The peaks corresponding to HAP are still marked with blue dots. The diffraction peaks at 2θ = 43.5° and 50.7° are attributed to the metallic Cu phase (JCPDS 04-009-2090) [3]. Another peak appearing at 23.5° in the Cu HAP sample is attributed to carbon [4].

[0215] Compared to the XRD of fresh samples, the most significant difference in post-reaction XRD for catalysts 1 to 4 prepared by wet impregnation is the reduction of CuO to metallic Cu. This is due to the generation of H2 during the WGS reaction. CuO tends to be reduced in a hydrogen atmosphere at temperatures above 250°C, as shown in the following reaction.

[0216] CuO + H₂ → Cu + H₂ For catalysts 5 to 8 prepared by coprecipitation, the HAP structure in the studied samples was well preserved after WGS testing.

[0217] Figure 6 XRD patterns were compared for fresh and post-reaction HAP-supported Cu and Fe catalyst 3 (CuFe-supported HAP) prepared by wet impregnation. The HAP peaks were observed in... Figure 6 The data is marked with blue dots, consistent with the previous section. After temperature screening, copper oxide was reduced to metallic copper in a hydrogen atmosphere. After 96 hours of stability testing, the number and size of HAP peaks decreased. Simultaneously, two new peaks were observed in the HAP samples loaded with Cu and Fe after the stability test, which may be attributed to Ca. 19 Cu2(PO4) 14 (JCPDS No. 46-0403) [5]. In Figure 6 In the diagram, the corresponding peaks are marked with orange diamond patterns. The appearance of these new peaks indicates that the hexagonal structure of HAP is weakening and partially transforming into apatite-like Ca. 19 Cu2(PO4) 14 Meanwhile, the size of the Cu peak decreases. (Ca) 19 Cu2(PO4) 14 The presence of Cu indicates that some Cu 0 The HAP structure is introduced, thereby replacing the Ca in HAP. 2+.

[0218] With Ca 19 Cu2(PO4) 14 The formation of Cu 2+ / Cu + The redox behavior of the catalyst is such that it exhibits enhanced catalytic activity for the WGS reaction. Furthermore, introducing Cu into the apatite structure significantly reduces Cu sintering during the WGS reaction, resulting in long-term stability in the 96-hour stability test.

[0219] 5. Conclusion HAP catalysts were synthesized using co-precipitation and impregnation methods, with Cu, Fe, and Pt added as active metals / promoters. The results showed that impregnation is a more efficient method for synthesizing HAP catalysts for WGS reactions. The Cu-supported HAP (catalyst 1) exhibited high catalytic performance in temperature screening tests, but its activity significantly decreased within the first 100 hours of stability testing. In contrast, the Cu- and Fe-supported HAP (catalyst 3) showed excellent catalytic activity for both low- and high-temperature WGS reactions at all tested temperatures (200 °C, 300 °C, 400 °C, and 500 °C). After 24 hours of testing, the catalytic activity increased to near the equilibrium conversion value. This may be attributed to the synergistic catalytic effect of Cu and Fe, where Cu actively catalyzes the low-temperature WGS reaction, while Fe enhances the high-temperature WGS reaction. Furthermore, a phase transition occurred during the long-term stability test—where Cu was introduced into the HAP structure to form Ca. 19 Cu2(PO4) 14 - This can help reduce copper sintering, resulting in long-term stable catalytic behavior.

[0220] In summary, a simple method for synthesizing Cu and Fe supported HAP catalysts is provided, which exhibit good performance in both low-temperature and high-temperature WGS reactions, with catalytic conversion approaching the equilibrium line after 24 hours of testing.

[0221] All references cited in this document, including publications, patent applications and patents, are cited in their entirety and to the extent that each reference is individually and explicitly stated to be incorporated herein by reference and presented in its entirety (to the maximum extent permitted by law).

[0222] All headings and subheadings used herein are for convenience only and should not be construed as limiting the invention in any way.

[0223] Unless otherwise specified in the description, the use of any and all examples or exemplary language (e.g., "such as") provided herein is intended only to better illustrate the invention and does not constitute a limitation on the scope of the invention. No language in the specification should be construed as indicating that any non-segmented element is necessary for the practice of the invention.

[0224] The citations and merging of patent documents in this article are for convenience only and do not reflect any opinion on the validity, patentability and / or enforceability of such patent documents.

[0225] This invention includes all modifications and equivalents to the subject matter described in the appended paragraphs, as permitted by applicable law.

[0226] References [1] Boukha, Z., Ayastuy, JL, González-Velasco, JR, & Gutiérrez-Ortiz, MA (2018). Water-gas shift reaction over a novel Cu-ZnO / HAPformulation: Enhanced catalytic performance in mobile fuel cell applications. Applied Catalysis A: General, 566, 1–14. https: / / doi.org / 10.1016 / j.apcata.2018.08.017 .

[0227] [2] Guo, J., Yu, H., Dong, F., Zhu, B., Huang, W.,&Zhang, S. (2017). High efficiency and stability of Au-Cu / hydroxyapatite catalyst for the oxidation of carbon monoxide. RSC Advances, 7(72), 45420–45431. https: / / doi.org / 10.1039 / c7ra08781k .

[0228] [3] Ivanauskas, Remigijus&Ancutiene, Ingrida&Milašien , Daiva&Ivanauskas, Algimantas&Bronusiene, Asta. (2022). Effect of Reducing Agent onCharacteristics and Antibacterial Activity of Copper-Containing Particles inTextile Materials. Materials. 15. 7623. DOI: 10.3390 / ma15217623 。

[0229] [4] Karimzadeh, Morteza., Niknam, Khodabakhsh., Manouchehri, Neda.,Tarokh, Dariush. A green route for the cross-coupling of azide anions witharyl halides under both base and ligand-free conditions: exceptionalperformance of a Cu2O–CuO–Cu–C nanocomposite, RSC Adv. , 2018, 8, 25785. http: / / dx.doi.org / 10.1039 / C8RA04608E 。

[0230] [5] Abdallah Amedlous, Othmane Amadine, Younes Essamlali, KarimDaanoun, Mina Aadilb andMohamed Zahouily, Aqueous-phase catalytichydroxylation of phenol with H2O2 by using a copper incorporated apatitenanocatalyst, RSC Adv. , 2019,9, 14132-14142. https: / / doi.org / 10.1039 / C9RA02021G 。

Claims

1. A method for producing a gaseous composition containing hydrogen, wherein the method comprises contacting a feed gas composition containing carbon monoxide and water with a catalyst composition containing a copper substance, an iron substance and hydroxyapatite (HAP).

2. The method of claim 1, wherein the copper substance in the catalyst composition is present in an amount of at least about 15% by weight of the catalyst composition.

3. The method of claim 1, wherein the copper substance in the catalyst composition is present in an amount of at least about 20% by weight of the catalyst composition.

4. The method of claim 1, wherein the copper substance in the catalyst composition is present in an amount of at least about 20% to about 30% by weight of the catalyst composition.

5. The method according to any one of the preceding claims, wherein the copper substance is selected from elemental copper, copper oxide, or mixtures thereof.

6. The method according to any one of the preceding claims, wherein the iron substance in the catalyst composition is present in an amount of at least about 3% by weight of the catalyst composition.

7. The method according to any one of the preceding claims, wherein the iron substance in the catalyst composition is present in an amount of about 3% by weight to about 10% by weight of the catalyst composition.

8. The method according to any one of the preceding claims, wherein the iron substance is selected from elemental iron, iron oxides, or mixtures thereof.

9. The method according to any one of the preceding claims, wherein the copper substance and the iron substance are present in a molar ratio of about 5:1 to about 1:

1.

10. The method according to any one of the preceding claims, wherein the catalyst composition comprises an iron substance, a copper substance, and HAP.

11. The method according to any one of claims 1 to 9, wherein the catalyst composition comprises at least one additional metallic substance.

12. The method of claim 11, wherein the additional metallic substance is a transition metal substance, such as a noble metal substance.

13. The method according to claim 11 or 12, wherein the additional metallic substance in the catalyst composition is present in an amount of about 0.05% by weight to about 1% by weight of the catalyst composition.

14. The method according to any one of the preceding claims, wherein the HAP is obtained by or can be obtained by wet chemical precipitation.

15. The method according to any one of the preceding claims, wherein the specific surface area of ​​the catalyst composition is about 20 m². 2 / g to approximately 30 m 2 / g.

16. The method according to any one of the preceding claims, wherein the total pore volume of the catalyst composition is about 0.01 cm³. 3 / g to approximately 0.09 cm 3 / g.

17. The method according to any one of the preceding claims, wherein the gaseous feedstock is contacted with the catalyst composition at a temperature of about 200°C to about 500°C.

18. A method for preparing a catalyst composition, comprising: (i) Mixing an aqueous solution of an iron salt or its hydrate and an aqueous solution of a copper salt or its hydrate with hydroxyapatite to provide a heterogeneous mixture; (ii) removing the aqueous solvent to provide a solid; and (iii) calcining the solid to provide the catalyst composition.

19. The catalyst composition obtained or obtainable by the method according to claim 18.

20. A catalyst composition comprising essentially copper or its oxide, iron or its oxide, and HAP.

21. The catalyst composition according to claim 20, comprising about 20% to about 25% by weight of copper or its oxide, about 5% to about 10% by weight of iron or its oxide, and HAP.

22. The catalyst composition according to claim 20 or 21, wherein the specific surface area of ​​the catalyst composition is about 20 m². 2 / g to approximately 30 m 2 / g, and / or a total pore volume of approximately 0.05 cm³. 3 / g to approximately 0.1 cm 3 / g.

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