Lignin-derived carbon-alloy-metal oxide heterojunction catalysts and methods of making same

Abstract

The present application relates to a kind of lignin-derived carbon-alloy-metal oxide heterojunction catalyst preparation method, it includes the following steps: 1) metal salt A and metal salt B are dissolved in organic solvent to obtain mixed solution C;2) lignin is dissolved in the mixed solution C, to obtain mixed solution D, and the mixed solution D and pretreated carrier are added into reaction kettle to carry out solvothermal reaction, after reaction, the reaction liquid in the reaction kettle is removed and is filtered, filter cake is washed, dried to obtain preliminary sample;3) preliminary sample prepared in step 2) is carried out high-temperature calcination in the mixed gas atmosphere of hydrogen and argon, to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.The present application uses metal salt A and metal salt B as metal source, simultaneously lignin as carbon source, after high-temperature calcination reduction, obtain lignin-derived carbon-alloy-metal oxide heterojunction catalyst.The catalyst prepared in the present application is low in cost, high in activity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemistry, in particular to a lignin-derived carbon-alloy-metal oxide heterojunction catalyst and a preparation method thereof. BACKGROUND

[0002] Due to the rapid consumption of fossil energy, serious problems such as environmental pollution and global warming have occurred, forcing people to seek cleaner and more environmentally friendly clean energy. Hydrogen energy, as one of the sustainable clean energy, has received extensive attention in recent years. Electrolysis of water to produce hydrogen is one of the most promising and practical technologies among many hydrogen production methods, and is also a hydrogen production method that has been studied the most. However, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) have a very high overpotential, resulting in a lot of energy loss. Although some studies have shown that replacing OER with urea oxidation reaction (UOR) can not only reduce the overpotential of the anode, but also treat urea wastewater from industry and agriculture, the HER / UOR performance of the catalyst needs to be further improved. Therefore, developing high-performance HER / UOR bifunctional catalytic materials is particularly important for improving the efficiency of electrolysis of urea.

[0003] Pt / Ir / Ru and other noble metal-based catalysts are currently efficient electrocatalysts for HER / UOR reactions, but their reserves are scarce and expensive, which seriously limits the widespread application of noble metals. Therefore, non-noble metal-based catalysts with certain activity and abundant reserves have attracted considerable attention. At the same time, in order to alleviate the consumption of fossil energy, researchers have conducted a lot of research on renewable biomass resources. Among them, lignin is the second largest biomass resource in the plant kingdom after cellulose, but its utilization rate is less than 10%. Experimental studies have shown that lignin-derived carbon has the advantages of chemical stability, good electrical conductivity, and multiple functional groups, and is considered to be a very promising carbon material.

[0004] Patent No. 202311156838.5, entitled "Highly dispersed lignin-derived Ru in-situ N-doped carbon material, its preparation method and application" discloses a catalyst for urea oxidation prepared from lignin as raw material. However, in this invention, noble metal ruthenium is used as raw material, increasing the cost of catalyst preparation; at the same time, the prepared material is a powder material, which is easy to agglomerate and reduce the catalytic activity.

[0005] Therefore, it is very important to develop lignin-derived carbon chelated non-noble metal-based catalysts with high activity and low cost. SUMMARY

[0006] Therefore, it is necessary to provide a HER / UOR bifunctional non-noble metal-based catalyst with high activity, high stability and low cost, namely a lignin-derived carbon-alloy-metal oxide heterojunction catalyst and a preparation method thereof.

[0007] To achieve the above object, the inventors provide a preparation method of a lignin-derived carbon-alloy-metal oxide heterojunction catalyst, comprising the following steps:

[0008] 1) dissolving metal salt A and metal salt B in an organic solvent to obtain a mixed solution C;

[0009] The metal salt A is one or a mixture of two or more of the following: chromium salt, manganese salt, iron salt, nickel salt, vanadium salt, cobalt salt, tungsten salt, copper salt, zinc salt, or molybdenum salt;

[0010] The metal salt B is one of the following: molybdenum salt, scandium salt, titanium salt, vanadium salt, chromium salt, zinc salt, gallium salt, germanium salt, strontium salt, yttrium salt, zirconium salt, niobium salt, cadmium salt, indium salt, tin salt, antimony salt, hafnium salt, tantalum salt, tungsten salt, rhenium salt, osmium salt, thallium salt, lead salt, bismuth salt, lanthanum salt, cerium salt, praseodymium salt, neodymium salt, samarium salt, europium salt, gadolinium salt, terbium salt, dysprosium salt, holmium salt, erbium salt, ytterbium salt or thulium salt;

[0011] The metal salt A and the metal salt B are different types of metal salts;

[0012] 2) dissolving lignin in the mixed solution C to obtain a mixed solution D, and then adding the mixed solution D and a pretreated carrier into a reaction kettle for solvothermal reaction, the reaction temperature is 100-200℃, the reaction time is 4-24 hours, after the reaction is completed, the reaction liquid in the reaction kettle is cooled to room temperature, and then filtered, the filter cake is washed and dried to obtain a preliminary sample;

[0013] The mass ratio of the metal salt A, the metal salt B and the lignin is 10-26.2:2:1-4;

[0014] The mass ratio of the metal salt A and the surface area of the pretreated carrier is 1-4:9 mg / cm 2 ;

[0015] 3) placing the preliminary sample prepared in step 2) in a calcination furnace, and passing a mixed gas of hydrogen and argon into the calcination furnace, the volume fraction of the hydrogen in the mixed gas is 10-50%, the temperature is raised to 400-1000℃ at a temperature rising rate of 3-15℃ / min, and high-temperature calcination is performed for 1-5 hours to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0016] The present application adopts the above scheme, taking metal salt A and metal salt B as metal sources, and taking lignin as a carbon source, first performing solvothermal synthesis to make lignin chelate coordinate with metal ions, then performing high-temperature calcination reduction, two or more metal salt A forms an alloy after calcination, or metal salt A and part of metal salt B form an alloy after calcination, and metal salt B forms a metal oxide after calcination, to obtain a lignin-derived carbon-alloy-metal oxide heterojunction catalyst. The lignin-derived carbon-alloy-metal oxide heterojunction catalyst has high catalytic activity and stability. Especially in step 1), metal salt A and metal salt B are easy to produce oxides, which are reduced to alloy-metal oxide heterojunctions after hydrogen argon calcination.

[0017] The lignin-derived carbon-alloy-metal oxide heterostructure catalyst prepared in the present application has the following advantages:

[0018] (1) Synergistic effect: In the heterostructure, the bonding effect between the interfaces of different components can improve the electron transfer rate. By combining metal alloy, metal oxide and lignin-derived carbon material, the conductivity, hydrophilicity, chemical stability and active site density of the finally prepared heterostructure catalyst can be controlled.

[0019] (2) Strain effect: In the heterostructure of the present application, the metal alloy, metal oxide and lignin-derived carbon material have different chemical composition and crystal structure, causing lattice strain such as tension and compression, affecting the adsorption energy of the site to the intermediate, which can further improve the catalytic activity of the material.

[0020] (3) Electronic interaction: In the heterostructure prepared in the present application, the different energy band arrangements of different phases will cause charge transfer at the interface, which is beneficial to the surface electron modulation of the heterostructure.

[0021] (4) Good stability: In the present application, lignin derivatives are used as carbon sources for carbon-coated catalysts, which can protect the catalyst in extreme environments, avoid acid and alkali corrosion of the catalyst, and make the prepared catalyst have good stability.

[0022] (5) Structural advantage: Lignin-derived carbon has a three-dimensional network structure, and its surface contains a large number of functional groups, which can greatly improve the catalytic activity of the prepared catalyst. In addition, since lignin-derived carbon is a high-performance and renewable biomass material, the preparation method of the present application has the advantages of high economic value, environmental protection, etc.

[0023] In the present application, the metal salt A is selected from the metal salt corresponding to the non-noble metal of the fourth period, which can adjust the electronic structure and enhance the HER / UOR performance of the catalyst.

[0024] The application has simple preparation process and low cost, and the catalyst prepared by the application has good HER and UOR catalytic performance in 1.0 mol / L potassium hydroxide and 0.5 mol / L urea electrolyte, and shows potentials of-39 / -262 / -356 mV and 1.28 / 1.40 / 1.46 V at-10 / -500 / -1000 mA cm -2 and 10 / 500 / 1000 mA cm -2 respectively. Since the catalyst prepared by the application has low cost and high activity, it has strong competitiveness in the fields of urea wastewater treatment and electrolytic hydrogen production.

[0025] Further, the carrier in step 1) is a metal carrier or a non-metal carrier, and the metal carrier is one of the following: a metal mesh, a metal sheet, a metal wire, a metal foil, an alloy mesh, an alloy sheet, or an alloy wire. Taking metal or non-metal as the carrier can provide a self-growth condition for the lignin-derived carbon-alloy-metal oxide heterojunction catalyst, so that the stability and activity of the catalyst are better.

[0026] Further, the metal mesh is one of the following: a nickel mesh, a cobalt mesh, a copper mesh, an iron mesh, a titanium mesh;

[0027] The alloy mesh is a nickel-iron mesh or a nickel-molybdenum mesh;

[0028] The metal sheet is one of the following: a nickel sheet, a cobalt sheet, a copper sheet, an iron sheet, a titanium sheet;

[0029] The alloy sheet is one of the following: a nickel-cobalt sheet, a nickel-copper sheet, an iron-copper sheet, a nickel-iron sheet, a stainless steel sheet, a nickel-molybdenum sheet, or a nickel-chromium sheet;

[0030] The metal wire is one of the following: a nickel wire, a cobalt wire, a copper wire, an iron wire, an aluminum wire, a titanium wire;

[0031] The alloy wire is a nickel-iron wire or a nickel-molybdenum wire;

[0032] The metal foil is one of the following: a nickel foil, a cobalt foil, a copper foil, an iron foil, a zinc foil, or a titanium foil;

[0033] The non-metal carrier is one of the following: a carbon black tube, a carbon nanotube, a carbon fiber sheet, an activated carbon fiber sheet, a carbon nanorod, a graphene block, an oxidized graphene block, an activated carbon block, a porous carbon block, a carbon cloth, a carbon felt, a glass fiber mesh, a layered graphite, organic glass, or expanded perlite.

[0034] Further, in the step 3), after the preliminary sample is calcined in the calcining furnace, two or more metal salts A are calcined to form an alloy, or one or more metal salts A and part of metal salt B are calcined to form an alloy, and the formed alloy is one or a mixture of two or more of the following: NiCo, MoNi, NiFe, NiMn, NiCu, NiCr, NiZn, NiV, NiW, CuCo, CuZn, CuMo, CuFe, CuMn, CuV, CuW, FeCr, FeMn, FeCo, FeZn, FeV, FeW, CoMn, CoZn, CoMo, CoCr, CoV, CoW, NiCoCu, CoCrMo, NiCoMo, NiFeMo, NiMnMo, NiCrMo, NiCuMo, NiCoFe, NiCoZn, NiCoCr, NiCoMn, NiCoV, NiCoW;

[0035] In the step 3), after the preliminary sample is calcined in the calcining furnace, the metal salt B is calcined to form a metal oxide, the metal oxide forms a heterojunction, and is loaded on a self-supporting carrier, and the formed metal oxide is one of the following: MoO2, Sc2O3, TiO2, V2O5, CrO3, ZnO, Ga2O3, GeO2, SrO, Y2O3, ZrO2, Nb2O5, CdO, In2O3, SnO2, Sb2O5, HfO2, Ta2O5, WO2, ReO3, OsO2, Tl2O3, Pb3O4, Bi2O3, La2O3, CeO2, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3.

[0036] Further, the pretreatment method of the carrier is: the untreated carrier is sequentially washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water, each for 3 times, and each washing time is 20-30 minutes. Through the pretreatment operation, the oxides and impurities on the surface of the carrier are effectively removed.

[0037] Further, the solvent added in step 1) is one of ethanol, ethylene glycol, methanol, isopropyl alcohol, glycerol, n-butyl alcohol, N,N-dimethylformamide, oleylamine, oleic acid, polyethylene glycol, toluene, acetonitrile, N,N-dimethylacetamide, dimethyl sulfoxide, pyridine, pyrrole, urea, aniline, N-methylaniline, N,N-dimethylaniline, N- ethylaniline, N,N-diethylaniline, diphenylamine, aniline hydrochloride, dioxodimethyl purine, phenylalanine, 2-hydroxypyridine, 2-aminopyridine, 2,6-diaminopyridine 2-methylpyridine, 3- aminopyridine, 4-methylpyridine, pentachloropyridine, 3-chloropyridine, 3-fluoropyridine, 3- bromopyridine, 2,3-diaminopyridine, 2-amino-3-chloropyridine, 2-pyrrolidone, 2-pyrrole carboxylic acid, 3-acetyl-2,4-dimethylpyrrole, hydroxyethyl pyrrolidone, 2-acetylpyrrole, 1- methylpyrrole, tetrahydropyrrole, pyrrole-2-carboxylic acid ethyl ester, 2,4-dimethylpyrrole, 4- acetylpyridine, 2-acetylpyrrole, N-methylpyrrole, or deionized water.

[0038] Further, the metal chromium salt in the metal salt A in step 1) is one of sodium chromate, potassium chromate, lead chromate, ammonium chromate, sodium dichromate, chromic acid anhydride, potassium dichromate, chromium oxide green, basic chromium sulfate;

[0039] The metal manganese salt in the metal salt A in step 1) is one of manganese chloride, manganese sulfate, manganese nitrate, manganese carbonate, manganese acetate, manganese oxalate, manganese phosphate, manganese bromide, manganese iodide, manganese fluoride, manganese perchlorate, manganese citrate, manganous sulfate, manganous acetate, manganous oxalate, manganous hydrogen phosphate, manganese pyrophosphate, manganese silicate, manganous metasilicate;

[0040] The metal iron salt in the metal salt A in step 1) is one of iron sulfate, iron chloride, iron nitrate, iron carbonate, ferrous sulfate, ferrous chloride, ferrous carbonate, iron tribromide, iron perchlorate, iron dihydrogen phosphate;

[0041] The metal vanadium salt in the metal salt A in step 1) is one of ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadium chloride, vanadium oxide, vanadium tetrachloride, sodium vanadate, vanadyl acetylacetonate, vanadyl triisopropylate, vanadyl triisopropoxy, vanadyl bisacetylacetonate;

[0042] The metal cobalt salt in the metal salt A in step 1) is one of cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt acetate, cobalt oxalate, cobalt phosphate, cobalt bromide, cobalt iodide, cobalt sulfide, cobalt fluoride, cobalt perchlorate, cobalt citrate, cobalt stearate, cobalt laurate, cobalt benzoate, ammonium cobalt chloride, ammonium cobalt sulfate, ammonium cobalt nitrate, cobalt hydrogen phosphate, cobaltous acetate;

[0043] The metal tungsten salt in the metal salt A in step 1) is one of the following: ammonium metatungstate, ammonium tungstate, potassium tungstate, sodium tungstate, phosphotungstic acid, sodium phosphotungstate, tungstosilicic acid, tungsten hexachloride, tungsten hexacarbonyl, tungsten isopropoxide;

[0044] The metal nickel salt in the metal salt A in step 1) is one of the following: nickel chloride, nickel acetylacetonate, nickel acetylacetonate, nickel acetate, nickel bromide, nickel iodide, nickel sulfate, nickel nitrate, nickel sulfate, nickel hypophosphite, nickel nitrate, nickel sulfamate, nickel subcarbonate, nickel formate, nickelocene, bis(triphenylphosphine) nickel bromide, bis(triphenylphosphine) nickel chloride;

[0045] The metal copper salt in the metal salt A in step 1) is one of the following: copper sulfate, copper chloride, copper carbonate, copper acetate, copper subcarbonate, copper gluconate, copper acetate, copper citrate;

[0046] The metal zinc salt in the metal salt A in step 1) is one of the following: zinc cyclohexanate, zinc acetate, zinc acetate, methyl zinc, zinc oxide, zinc glycinate, zinc orotate, zinc picolinate, zinc gluconate, zinc sulfate;

[0047] The metal molybdenum salt in the metal salt A in step 1) is one of the following: molybdic acid, ammonium molybdate tetrahydrate, ammonium heptamolybdate, ammonium dimolybdate, sodium molybdate, phosphomolybdic acid, ammonium phosphomolybdate, sodium phosphomolybdate, molybdenum chloride, lithium molybdate, potassium molybdate, molybdenum hexacarbonyl, molybdenum acetylacetonate, molybdenum isopropoxide;

[0048] The metal molybdenum salt in the metal salt B in step 1) is one of the following: molybdic acid, ammonium molybdate tetrahydrate, ammonium heptamolybdate, ammonium dimolybdate, sodium molybdate, phosphomolybdic acid, ammonium phosphomolybdate, sodium phosphomolybdate, molybdenum chloride, lithium molybdate, potassium molybdate, molybdenum hexacarbonyl, molybdenum acetylacetonate, molybdenum isopropoxide; The metal salt B is selected from the following types because they include most of the non-noble metal elements of the fourth, fifth and sixth periods, and the results are universal.

[0049] The metal scandium salt in the metal salt B in step 1) is one of the following: scandium nitrate, scandium chloride, scandium sulfate, scandium acetate, scandium phosphate, scandium fluoride, scandium oxalate, scandium carbonate;

[0050] The metal titanium salt in the metal salt B in step 1) is one of the following: titanium acid, titanium tetrachloride, titanium trichloride, titanium orthosulfate, titanium oxysulfate, titanium orthoacid, sodium titanium silicate;

[0051] The metal vanadium salt in the metal salt B in step 1) is one of the following: ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadium chloride, vanadium oxide, vanadium tetrachloride, sodium vanadate, vanadium acetylacetonate, vanadyl triisopropoxide, vanadyl acetylacetonate, vanadyl triisopropoxide, diacetylacetonate vanadium oxide;

[0052] The metal chromium salt in the metal salt B in step 1) is one of the following: sodium chromate, potassium chromate, lead chromate, ammonium chromate, sodium dichromate, chromic anhydride, potassium dichromate, chromium oxide green, basic chromium sulfate;

[0053] The metal zinc salt in the metal salt B in step 1) is one of the following: zinc cyclohexanoate, zinc acetate, zinc acetate, methyl zinc, zinc oxide, zinc glycinate, zinc orotate, zinc picolinate, zinc gluconate, zinc sulfate;

[0054] The metal gallium salt in the metal salt B in step 1) is one of the following: gallium nitrate, gallium sulfate, gallium chloride, gallium fluoride, gallium hydroxide, gallium acetate;

[0055] The metal germanium salt in the metal salt B in step 1) is one of the following: germanate, metagermanate, digermanate, tetra-germanate;

[0056] The metal strontium salt in the metal salt B in step 1) is one of the following: strontium sulfate, strontium chloride, strontium nitrate, strontium carbonate, strontium hydroxide, strontium acetate;

[0057] The metal yttrium salt in the metal salt B in step 1) is one of the following: yttrium chloride, yttrium nitrate, yttrium sulfate, yttrium acetate, yttrium oxalate, yttrium fluoride;

[0058] The metal zirconium salt in the metal salt B in step 1) is one of the following: zirconium chloride, zirconium sulfate, zirconium carbonate, zirconium oxychloride, zirconium nitrate, zirconium acetate, zirconium fluoride;

[0059] The metal niobium salt in the metal salt B in step 1) is one of the following: niobium chloride, niobium fluoride, niobium pentachloride, niobium oxide, niobium oxalate;

[0060] The metal cadmium salt in the metal salt B in step 1) is one of the following: cadmium sulfate, cadmium chloride, cadmium nitrate, cadmium acetate, cadmium carbonate, cadmium iodide;

[0061] The metal indium salt in the metal salt B in step 1) is one of the following: indium chloride, indium nitrate, indium sulfate, indium iodide, indium acetate;

[0062] The metal tin salt in the metal salt B in step 1) is one of the following: tin chloride, tin sulfate, sodium stannate, tin fluoride, tin carbonate, tin acetate;

[0063] The metal antimony salt in the metal salt B in step 1) is one of the following: antimony chloride, antimony trioxide, potassium antimony tartrate, antimony acetate;

[0064] The hafnium salt in the metal salt B in step 1) is one of the following: hafnium chloride, hafnium fluoride, hafnium sulfate, hafnium nitrate, hafnium acetate, hafnium oxide;

[0065] The tantalum salt in the metal salt B in step 1) is one of the following: tantalum chloride, potassium heptafluotantalate, tantalum methoxide, tantalum ethoxide, tantalum propoxide, tantalum butoxide, tantalum isobutoxide;

[0066] The tungsten salt in the metal salt B in step 1) is one of the following: ammonium metatungstate, ammonium tungstate, potassium tungstate, sodium tungstate, phosphotungstic acid, sodium phosphotungstate, tungstosilicic acid, tungsten hexachloride, tungsten hexacarbonyl, tungsten isopropoxide;

[0067] The rhenium salt in the metal salt B in step 1) is one of the following: dioxo-rhenium, rhenium dioxide, rhenium trioxide, rhenium disulfide, rhenium diboride, rhenium tetrafluoride, rhenium pentafluoride, perrhenic acid;

[0068] The osmium salt in the metal salt B in step 1) is one of the following: osmium tetroxide, osmium dioxide, sodium osmate hexachloride, osmium disulfide, osmium ditelluride;

[0069] The lead salt in the metal salt B in step 1) is one of the following: lead nitrate, lead acetate, lead chloride, lead arsenate, lead oxide;

[0070] The bismuth salt in the metal salt B in step 1) is one of the following: bismuth nitrate, bismuth chloride, bismuth sulfate;

[0071] The lanthanum salt in the metal salt B in step 1) is one of the following: lanthanum nitrate, lanthanum chloride, lanthanum acetate, lanthanum sulfate;

[0072] The cerium salt in the metal salt B in step 1) is one of the following: cerium nitrate, cerium sulfate, cerium chloride, cerium oxalate;

[0073] The praseodymium salt in the metal salt B in step 1) is one of the following: praseodymium chloride, praseodymium oxide, praseodymium nitrate, praseodymium sulfate;

[0074] The neodymium salt in the metal salt B in step 1) is one of the following: neodymium nitrate, neodymium chloride, neodymium sulfate, neodymium acetate;

[0075] The samarium salt in the metal salt B in step 1) is one of the following: samarium nitrate, samarium carbonate;

[0076] The europium salt in the metal salt B in step 1) is one of the following: europium fluoride, europium nitrate;

[0077] The gadolinium salt in the metal salt B in step 1) is one of the following: gadolinium sulfate, gadolinium nitrate;

[0078] The terbium salt in the metal salt B in step 1) is one of the following: terbium nitrate, terbium chloride, terbium sulfate;

[0079] The dysprosium salt in the metal salt B in step 1) is one of the following: dysprosium nitrate, dysprosium sulfate;

[0080] The holmium salt in the metal salt B in step 1) is one of the following: holmium chloride, holmium sulfate;

[0081] The erbium salt in the metal salt B in step 1) is one of the following: erbium nitrate, erbium chloride, erbium sulfate;

[0082] The thulium salt in the metal salt B in step 1) is one of the following: thulium chloride, thulium nitrate;

[0083] The ytterbium salt in the metal salt B in step 1) is one of the following: ytterbium chloride, ytterbium sulfate.

[0084] Further, the lignin in step 2) is one of the following: alkaline lignin, dealkaline lignin, sodium lignosulfonate, sulfate lignin, hydrolyzed lignin, organic solvent lignin, pyrolysis lignin, enzymatic hydrolysis lignin, carboxymethylated lignin, aminated lignin, phosphatized lignin, carboxylated lignin, sulfonated lignin or sulfidized lignin.

[0085] Further, in step 2), the mixed solution D is first subjected to ultrasonic stirring and dispersion to be completely dissolved to obtain a mixed suspension liquid, and then the mixed suspension liquid and the pretreated carrier are added into a reaction kettle to perform a solvothermal reaction. Through ultrasonic treatment, the lignin can be quickly dissolved.

[0086] The application further discloses a lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared by the preparation method.

[0087] Compared with the prior art, the technical scheme has the following advantages: the application adopts the above scheme, uses metal salt A and metal salt B as metal sources, and uses lignin as a carbon source, and first performs solvothermal synthesis to make the lignin chelate and coordinate with metal ions, and then performs high-temperature calcination reduction to obtain a lignin-derived carbon-alloy-metal oxide heterojunction catalyst. The catalyst prepared by the application has low cost and high activity, and has strong competitiveness in the fields of treating urea wastewater and electrolytic hydrogen production. BRIEF DESCRIPTION OF DRAWINGS

[0088] Figure 1 The XRD pattern of the lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in Example 1 of the application;

[0089] Figure 2 TEM images of a lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared for Example 1 of the present invention;

[0090] Figure 3 Raman data of a lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared for Example 1 of the present invention;

[0091] Figure 4 Linear sweep voltammetry (LSV) curve data of a catalyst prepared for Example 1 of the present invention and 20 wt.% of a commercial Pt / C catalyst in a 1.0 mol / L potassium hydroxide and 0.5 mol / L urea mixed solution;

[0092] Figure 5 Tafel slope curve data of a catalyst prepared for Example 1 of the present invention and 20 wt.% of a commercial Pt / C catalyst in a 1.0 mol / L potassium hydroxide and 0.5 mol / L urea mixed solution;

[0093] Figure 6 Urea oxidation LSV curve data of a catalyst prepared for Example 1 of the present invention and 40 wt.% of a commercial RuO2 / C catalyst in a 1.0 mol / L potassium hydroxide and 0.5 mol / L urea mixed solution;

[0094] Figure 7 Tafel slope curve data of a catalyst prepared for Example 1 of the present invention and 40 wt.% of a commercial RuO2 / C catalyst in a 1.0 mol / L potassium hydroxide and 0.5 mol / L urea mixed solution. DETAILED DESCRIPTION

[0095] To make the technical content, structural features, purposes and effects of the technical solutions clear, the following will be described in detail in combination with specific embodiments and the accompanying drawings.

[0096] Example 1

[0097] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst was prepared by the following method:

[0098] (1) An untreated nickel mesh was rinsed with absolute ethanol, 1.0 mol / L hydrochloric acid and deionized water for 3 times, each time for 30 minutes (the surface area was 9 cm 2 );

[0099] (2) 1.68 g of nickel nitrate (metal salt A) and 0.256 g of ammonium molybdate tetrahydrate (metal salt B) were dissolved in 30 mL of deionized water to obtain a mixed solution C;

[0100] (3) 0.4 g of alkaline lignin (a commercially available product, purchased from Shanghai Maikelin Biochemical Technology Co., Ltd., brand: L832292-100 g) was dissolved in the mixed solution C and dispersed by ultrasonic stirring. The ultrasonic stirring was performed for 10 min, followed by stirring for 10 min to obtain a mixed suspension. The mixed suspension was placed in a reaction kettle with a capacity of 50 mL, and the nickel mesh treated in step (1) (surface area: 9 cm 2 ) was added to perform a solvothermal reaction. The solvothermal reaction temperature was 180°C, and the reaction was kept for 6 hours. After natural cooling, the product obtained after the solvothermal reaction was taken out, filtered, washed, and vacuum dried for 24 hours to obtain a primary sample.

[0101] (4) The primary sample obtained in step (3) was placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounted for 15% of the mixed gas by volume) was introduced. The temperature was increased to 500°C at a rate of 3°C / min, and the high-temperature calcination was continued for 2 hours to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0102] The lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in this example was subjected to XRD detection, and the detected XRD graph is shown in Figure 1 .

[0103] As can be seen from Figure 1 , the X-ray diffraction (XRD) standard card corresponding to the catalyst prepared in this example is NiO (PDF #89-7131) and MoNi4 (PDF #65-5480), which indicates that the lignin-derived carbon-alloy-metal oxide heterojunction catalyst is successfully prepared.

[0104] The catalyst prepared in Example 1 was detected by transmission electron microscopy with different scales, and the specific detection results are shown in Figure 2 a-e. Among them, as can be seen from Figure 2 a-c, the lattice fringes of MoNi4 (310) and NiO (200) are 0.181 nm and 0.209 nm, respectively, indicating the successful preparation of the lignin-derived carbon-alloy-metal oxide heterojunction catalyst. And Figure 2 d-e shows that it has a lot of mesoporous structure, which is beneficial to the gas-liquid transmission of the catalyst to enhance the HER and UOR performance of the catalyst.

[0105] The lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in Example 1 was subjected to Raman spectrum (Raman) detection, and the detection data is shown in Figure 3 .

[0106] As can be seen from Figure 3 , the D peak and the G peak are both Raman characteristic peaks of C, and are respectively at 1350 cm -1and 1580 cm -1 nearby, indicating that the catalyst prepared in this embodiment has lignin-derived carbon.

[0107] Example 2

[0108] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0109] (1) The untreated copper mesh is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 3 times, with each time being 30 minutes (the surface area is 9 cm 2 ) ;

[0110] (2) 4.0 g of sodium dichromate and 0.8 g of scandium fluoride are dissolved in 30 mL of ethanol to obtain a mixed solution C;

[0111] (3) 0.4 g of alkaline lignin (a commercially available product, purchased from Shanghai Maikelin Biochemical Technology Co., Ltd., brand: L832292-100 g) is dissolved in the mixed solution, ultrasonic stirring is performed for dispersion, ultrasonic stirring is performed for 10 min first, and then stirring is performed for 10 min, to obtain a mixed suspension, the mixed suspension is placed in a reaction kettle with a capacity of 50 mL, and the copper mesh (the surface area is 9 cm 2 ) treated in step (1) is added for solvothermal reaction, the solvothermal reaction temperature is 160°C, and the reaction is kept for 8 hours, after natural cooling, the product obtained after the solvothermal reaction is taken out, filtered, washed, and vacuum dried for 24 hours to obtain a primary sample

[0112] (4) The primary sample obtained in step (3) is placed in a tube furnace, a mixed gas of hydrogen and argon (the volume fraction of hydrogen in the mixed gas is 15%) is introduced, the temperature is increased to 500°C at a speed of 3°C / min, and high-temperature calcination is continued for 2 hours, to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0113] Example 3

[0114] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0115] (1) The untreated nickel wire is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 3 times, with each time being 30 minutes (the surface area is 9 cm 2 ) ;

[0116] (2) 2.62 g of manganese phosphate and 0.2 g of titanium orthosulfate are dissolved in 30 mL of ethylene glycol to obtain a mixed solution C;

[0117] (3) 0.4 g of sulfonated lignin (hydrophilic sulfonic acid groups are introduced into the alkaline lignin used in Example 1 by high-temperature sulfonation or sulfomethylation) is dissolved in the mixed solution, ultrasonic stirring and dispersion are performed, ultrasonic stirring is performed for 10 min, followed by stirring for 10 min, a mixed suspension liquid is obtained, the mixed suspension liquid is placed in a reaction kettle with a capacity of 50 mL, the nickel wire treated in step (1) (a surface area of 9 cm 2 ) is added, and a solvothermal reaction is performed, the solvothermal reaction temperature is 160°C, the reaction is kept for 6 hours, after natural cooling, the product obtained after the solvothermal reaction is taken out, filtration, washing, and vacuum drying for 24 hours are performed to obtain a primary sample

[0118] (4) The primary sample obtained in step (3) is placed in a tube furnace, a mixed gas of hydrogen and argon (hydrogen accounts for 10% of the volume fraction of the mixed gas) is introduced, the temperature is increased to 500°C at a rate of 5°C / min, and high-temperature calcination is continued for 2 hours to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0119] Example 4

[0120] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0121] (1) The untreated nickel-iron wire is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid, and deionized water for 3 times, each time for 30 min (a surface area of 9 cm 2 );

[0122] (2) 1.68 g of sodium phosphotungstate, 1.68 g of cobalt phosphate, and 0.256 g of vanadium chloride are dissolved in 30 mL of isopropyl alcohol to obtain a mixed solution C;

[0123] (3) 0.4 g of sulfonated lignin (hydrophilic sulfonic acid groups are introduced into the alkaline lignin used in Example 1 by high-temperature sulfonation or sulfomethylation) is dissolved in the mixed solution, ultrasonic stirring and dispersion are performed, ultrasonic stirring is performed for 10 min, followed by stirring for 10 min, a mixed suspension liquid is obtained, the mixed suspension liquid is placed in a reaction kettle with a capacity of 50 mL, the nickel wire treated in step (1) (a surface area of 9 cm 2 ) is added, and a solvothermal reaction is performed, the solvothermal reaction temperature is 160°C, the reaction is kept for 6 hours, after natural cooling, the product obtained after the solvothermal reaction is taken out, filtration, washing, and vacuum drying for 24 hours are performed to obtain a primary sample

[0124] (4) The primary sample obtained in step (3) is placed in a tube furnace, a mixed gas of hydrogen and argon (hydrogen accounts for 10% of the volume fraction of the mixed gas) is introduced, the temperature is increased to 500°C at a rate of 5°C / min, and high-temperature calcination is continued for 2 hours to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0125] Example 5

[0126] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0127] (1) The untreated zinc foil is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 3 times, 30 minutes each time (the surface area is 9 cm 2 ) ;

[0128] (2) 1.5 g of nickel iodide, 1.5 g of copper acetate and 0.256 g of ammonium chromate are dissolved in 30 mL of methanol to obtain a mixed solution C;

[0129] (3) 0.4 g of sodium lignosulfonate (a commercially available product, purchased from Tianjin Damao Chemical Reagent Factory, model: 8061-51-6) is dissolved in the mixed solution, ultrasonic stirring is performed for dispersion, ultrasonic stirring is performed for 10 min first, and then stirring is performed for 10 min, to obtain a mixed suspension, the mixed suspension is placed in a reaction kettle with a capacity of 50 mL, and the zinc foil (the surface area is 9 cm 2 ) treated in step (1) is added for solvothermal reaction, the solvothermal reaction temperature is 160℃, and the reaction is kept for 6 hours, after natural cooling, the product obtained after solvothermal reaction is taken out, filtered, washed, and vacuum dried for 24 hours to obtain a primary sample

[0130] (4) The primary sample obtained in step (3) is placed in a tube furnace, a mixed gas of hydrogen and argon (hydrogen accounts for 15% of the volume fraction of the mixed gas) is introduced, the temperature is increased to 600℃ at a speed of 10℃ / min, and high-temperature calcination is continued for 3 hours, to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0131] Example 6

[0132] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0133] (1) The untreated carbon nanotubes are washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 3 times, 30 minutes each time (the surface area is 9 cm 2 ) ;

[0134] (2) 1.35 g of zinc oxide, 1.35 g of chromic anhydride, and 0.3 g of copper acetate are dissolved in 30 mL of N,N-dimethylacetamide to obtain a mixed solution C;

[0135] (3) 0.4 g of the sulfite ligin (lignin extracted from sulfite pulping black liquor, purchased from Shandong Sun Paper Co., Ltd.) was dissolved in the mixed solution and dispersed by ultrasonic stirring. First, ultrasonic stirring was performed for 10 min, and then stirring was performed for 10 min to obtain a mixed suspension liquid. The mixed suspension liquid was placed in a reaction kettle with a capacity of 50 mL, and the carbon nanotubes treated in step (1) (surface area of 9 cm 2 ) were added to perform a solvothermal reaction. The solvothermal reaction temperature was 200°C, and the reaction was kept for 4 h. After natural cooling, the product obtained after the solvothermal reaction was taken out and filtered, washed, and vacuum dried for 24 h to obtain a primary sample

[0136] (4) The primary sample obtained in step (3) was placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounted for 20% of the volume fraction of the mixed gas) was introduced. The temperature was increased to 700°C at a rate of 3°C / min, and high-temperature calcination was continued for 2 h to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0137] Example 7

[0138] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst was prepared by the following method:

[0139] (1) The untreated titanium mesh was rinsed with anhydrous ethanol, 1.0 mol / L hydrochloric acid, and deionized water for 3 times, each time for 30 min (surface area of 9 cm 2 );

[0140] (2) 1.68 g of iron nitrate, 1.68 g of manganese iodide, and 0.4 g of cobalt bromide were dissolved in 30 mL of N-ethyl aniline to obtain a mixed solution C;

[0141] (3) 0.4 g of the enzymatic lignin (a byproduct of the preparation of fuel ethanol by biomass fermentation, purchased from Shandong Longli Science and Technology Biotechnology Co., Ltd.) was dissolved in the mixed solution and dispersed by ultrasonic stirring. First, ultrasonic stirring was performed for 10 min, and then stirring was performed for 10 min to obtain a mixed suspension liquid. The mixed suspension liquid was placed in a reaction kettle with a capacity of 50 mL, and the titanium mesh treated in step (1) (surface area of 9 cm 2 ) was added to perform a solvothermal reaction. The solvothermal reaction temperature was 100°C, and the reaction was kept for 24 h. After natural cooling, the product obtained after the solvothermal reaction was taken out and filtered, washed, and vacuum dried for 24 h to obtain a primary sample

[0142] (4) The primary sample obtained in step (3) is placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounts for 40% of the volume fraction of the mixed gas) is introduced, and the temperature is raised to 900°C at a rate of 10°C / min, and the high-temperature calcination is continued for 2 hours, to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0143] Example 8

[0144] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0145] (1) The untreated graphene block is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 2 times, and each time is 20 minutes (the surface area is 9 cm 2 );

[0146] (2) 1.0 g of tungsten hexachloride, 1.0 g of cobalt hydrogen phosphate and 0.2 g of zinc acetate are dissolved in 30 mL of n-butanol to obtain a mixed solution C;

[0147] (3) 0.4 g of dealkalized lignin (a commercially available product, purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., model: L195713-100g) is dissolved in the mixed solution, and ultrasonic stirring is performed for dispersion, first ultrasonic stirring for 10 min, and then stirring for 10 min, to obtain a mixed suspension, which is placed in a reaction kettle with a capacity of 50 mL, and the graphene block (the surface area is 9 cm 2 ) treated in step (1) is added for solvothermal reaction, the solvothermal reaction temperature is 140°C, and the reaction is kept for 10 hours, after natural cooling, the product obtained after the solvothermal reaction is taken out, filtered, washed and vacuum dried for 24 hours to obtain a primary sample

[0148] (4) The primary sample obtained in step (3) is placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounts for 40% of the volume fraction of the mixed gas) is introduced, and the temperature is raised to 900°C at a rate of 10°C / min, and the high-temperature calcination is continued for 2 hours, to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0149] Example 9

[0150] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0151] (1) The untreated nickel-molybdenum wire is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 2 times, and each time is 30 minutes (the surface area is 9 cm 2 );

[0152] (2) 1.5 g of nickel formate, 1.5 g of zinc acetate, and 0.32 g of digermanate were dissolved in 30 mL of toluene to obtain a mixed solution C;

[0153] (3) 0.4 g of hydrolyzed lignin (hydrolyzed lignin is lignin obtained after hydrolysis of plant fiber raw materials to remove cellulose and hemicellulose, and was purchased from Shandong Sunshine Paper Co., Ltd.) was dissolved in the mixed solution and dispersed by ultrasonic stirring. First, ultrasonic stirring was performed for 10 min, and then stirring was performed for 10 min to obtain a mixed suspension liquid. The mixed suspension liquid was placed in a reaction kettle with a capacity of 50 mL, and the nickel-molybdenum wire treated in step (1) (a surface area of 9 cm 2 ) was added to perform a solvothermal reaction. The solvothermal reaction temperature was 180°C, and the reaction was kept for 6 hours. After natural cooling, the product obtained after the solvothermal reaction was taken out and filtered, washed, and vacuum dried for 24 hours to obtain a primary sample

[0154] (4) The primary sample obtained in step (3) was placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounts for 50% of the volume fraction of the mixed gas) was introduced. The temperature was increased to 1000°C at a rate of 15°C / min, and high-temperature calcination was continued for 1 hour to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0155] Example 10

[0156] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst was prepared by the following method:

[0157] (1) The untreated iron foil was rinsed with anhydrous ethanol, 1.0 mol / L hydrochloric acid, and deionized water for 2 times, each time for 30 minutes (a surface area of 9 cm 2 );

[0158] (2) 1.4 g of chromium oxide green, 1.4 g of cobalt bromide, and 0.256 g of gallium fluoride were dissolved in 30 mL of polyethylene glycol to obtain a mixed solution C;

[0159] (3) 0.4 g of delignified lignin (a commercially available product, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., model number: L195713-100 g) was dissolved in the mixed solution and dispersed by ultrasonic stirring. First, ultrasonic stirring was performed for 10 min, and then stirring was performed for 10 min to obtain a mixed suspension liquid. The mixed suspension liquid was placed in a reaction kettle with a capacity of 50 mL, and the iron foil treated in step (1) (a surface area of 9 cm 2 ) was added to perform a solvothermal reaction. The solvothermal reaction temperature was 150°C, and the reaction was kept for 10 hours. After natural cooling, the product obtained after the solvothermal reaction was taken out and filtered, washed, and vacuum dried for 24 hours to obtain a primary sample

[0160] (4) The primary sample obtained in step (3) is placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounts for 50% of the volume fraction of the mixed gas) is introduced, and the temperature is raised to 500°C at a rate of 10°C / min, and high-temperature calcination is continued for 2 hours, to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0161] Example 11

[0162] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0163] (1) The untreated carbon fiber sheet is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 2 times, and each time is 30 minutes (the surface area is 9 cm 2 );

[0164] (2) 1.68 g of iron chloride, 1.68 g of tungsten isopropoxide, and 0.256 g of yttrium oxalate are dissolved in 30 mL of 2,6-diaminopyridine 2-methylpyridine to obtain a mixed solution C;

[0165] (3) 0.4 g of phosphonated lignin (the alkaline lignin used in Example 1 is modified by phosphonation) is dissolved in the mixed solution, and ultrasonic stirring is performed for dispersion, first ultrasonic stirring for 10 min, and then stirring for 10 min, to obtain a mixed suspension, which is placed in a reaction kettle with a capacity of 50 mL, and the carbon fiber sheet treated in step (1) (the surface area is 9 cm 2 ) is added for solvothermal reaction, the solvothermal reaction temperature is 160°C, and the reaction is kept for 10 hours, after natural cooling, the product obtained after solvothermal reaction is taken out, filtered, washed, and vacuum dried for 24 hours to obtain a primary sample

[0166] (4) The primary sample obtained in step (3) is placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounts for 30% of the volume fraction of the mixed gas) is introduced, and the temperature is raised to 700°C at a rate of 5°C / min, and high-temperature calcination is continued for 2 hours, to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0167] Example 12

[0168] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0169] (1) The untreated copper sheet is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 2 times, and each time is 30 minutes (the surface area is 9 cm 2 );

[0170] (2) 1.35 g of molybdenum chloride, 1.35 g of nickel bromide, and 0.5 g of zirconium acetate were dissolved in 30 mL of 3-aminopyridine to obtain a mixed solution C;

[0171] (3) 0.4 g of carboxylated lignin (alkaline lignin of Example 1 was modified by carboxylation) was dissolved in the mixed solution, and ultrasonic stirring dispersion was performed, first ultrasonic stirring for 10 min, and then stirring for 10 min to obtain a mixed suspension liquid. The mixed suspension liquid was placed in a reaction kettle with a capacity of 50 mL, and the copper sheet (surface area of 9 cm 2 ) treated in step (1) was added to perform solvothermal reaction. The solvothermal reaction temperature was 150°C, and the reaction was kept for 8 hours. After natural cooling, the product obtained after the solvothermal reaction was taken out, filtered, washed, and vacuum dried for 24 hours to obtain a primary sample

[0172] (4) The primary sample obtained in step (3) was placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounted for 20% of the mixed gas by volume) was introduced. The temperature was increased to 700°C at a rate of 5°C / min, and high-temperature calcination was continued for 3 hours to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0173] Example 13

[0174] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst was prepared by the following method:

[0175] (1) The untreated stainless steel sheet was washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid, and deionized water for 2 times, each time for 30 minutes (surface area of 9 cm 2 );

[0176] (2) 1.38 g of cobalt laurate, 1.38 g of copper acetate, and 0.4 g of niobium chloride were dissolved in 30 mL of 2,3-diaminopyridine to obtain a mixed solution C;

[0177] (3) 0.4 g of alkaline lignin (a commercially available product, purchased from Shanghai Maikelin Biochemical Technology Co., Ltd., model: L832292-100 g) was dissolved in the mixed solution, and ultrasonic stirring dispersion was performed, first ultrasonic stirring for 10 min, and then stirring for 10 min to obtain a mixed suspension liquid. The mixed suspension liquid was placed in a reaction kettle with a capacity of 50 mL, and the stainless steel sheet (surface area of 9 cm 2 ) treated in step (1) was added to perform solvothermal reaction. The solvothermal reaction temperature was 170°C, and the reaction was kept for 10 hours. After natural cooling, the product obtained after the solvothermal reaction was taken out, filtered, washed, and vacuum dried for 24 hours to obtain a primary sample

[0178] (4) The primary sample obtained in step (3) is placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounts for 45% of the volume fraction of the mixed gas) is introduced, and the temperature is raised to 600°C at a rate of 6°C / min, and the high-temperature calcination is continued for 2 hours, to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0179] Example 14

[0180] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0181] (1) The untreated cobalt mesh is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 2 times, and each time is 30 minutes (the surface area is 9 cm 2 );

[0182] (2) 1.3 g of zinc glycinate, 1.3 g of ammonium dimolybdate and 0.25 g of indium chloride are dissolved in 30 mL of 2-amino-3-chloropyridine to obtain a mixed solution C;

[0183] (3) 0.5 amineated lignin (the basic lignin of Example 1 is modified by amineation) is dissolved in the mixed solution, and ultrasonic stirring is performed, first ultrasonic stirring for 10 min, and then stirring for 10 min, to obtain a mixed suspension, which is placed in a reaction kettle with a capacity of 50 mL, and the cobalt mesh (the surface area is 9 cm 2 ) treated in step (1) is added for solvothermal reaction, the solvothermal reaction temperature is 150°C, and the reaction is kept for 10 hours, after natural cooling, the product obtained after the solvothermal reaction is taken out, filtered, washed and vacuum dried for 24 hours to obtain a primary sample

[0184] (4) The primary sample obtained in step (3) is placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounts for 25% of the volume fraction of the mixed gas) is introduced, and the temperature is raised to 500°C at a rate of 5°C / min, and the high-temperature calcination is continued for 3 hours, to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0185] Example 15

[0186] A lignin-derived carbon-alloy-metal oxide heterojunction catalyst is prepared by the following method:

[0187] (1) The untreated activated carbon block is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water for 2 times, and each time is 30 minutes (the surface area is 9 cm 2 );

[0188] (2) 1.2 g of sodium orthovanadate, 1.2 g of manganese hydrogen phosphate, and 0.35 g of hafnium chloride were dissolved in 30 mL of N-methylpyrrole to obtain a mixed solution C;

[0189] (3) 0.4 g of carboxylated lignin (the alkaline lignin of Example 1 was modified by carboxylation) was dissolved in the mixed solution, ultrasonically stirred and dispersed, ultrasonically stirred for 10 min, and then stirred for 10 min to obtain a mixed suspension. The mixed suspension was placed in a reaction kettle with a capacity of 50 mL, and the activated carbon block (surface area of 9 cm 2 ) treated in step (1) was added to perform a solvothermal reaction. The solvothermal reaction temperature was 150°C, and the reaction was kept for 10 hours. After natural cooling, the product obtained after the solvothermal reaction was taken out, filtered, washed, and vacuum dried for 24 hours to obtain a primary sample

[0190] (4) The primary sample obtained in step (3) was placed in a tube furnace, and a mixed gas of hydrogen and argon (hydrogen accounted for 50% of the volume fraction of the mixed gas) was introduced. The temperature was increased to 400°C at a rate of 10°C / min, and high-temperature calcination was continued for 5 hours to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

[0191] The lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in Examples 1-15 was tested for HER and UOR in a 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution, and the specific operation was as follows:

[0192] (1) The lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in Examples 1-15 was taken as the working electrode, and an electrochemical workstation was used for electrochemical testing.

[0193] (2) The test conditions were as follows: a carbon rod was used as the counter electrode, a mercury / mercury oxide electrode was used as the reference electrode, the catalyst prepared in Examples 1-15 was taken as the working electrode, 15 sets of three-electrode test systems were formed, and then HER and UOR electrochemical performance tests were performed in a 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution alkaline medium. The results are shown in Tables 1 and 2.

[0194] Table 1. HER electrochemical performance in a 1.0 mol / L potassium hydroxide and 0.5 mol / L urea mixed solution

[0195]

[0196] Table 2. UOR electrochemical performance in a 1.0 mol / L potassium hydroxide and 0.5 mol / L urea mixed solution

[0197]

[0198] As can be seen from Table 1, 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution were used as electrolytes for detection. -2 At a potential of -500 mA cm, the electrochemical hydrogen evolution performance of the lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared by the present invention is as high as -39 mV in Example 1 and as low as -98 mV in Example 8; -2 At a potential of -1000 mA cm, the electrochemical hydrogen evolution performance of the catalyst prepared by the present invention is the highest of -390 mV in Example 8 and the lowest of -262 mV in Example 1; -2 At a potential of , the electrochemical hydrogen evolution performance of the catalyst prepared by the present invention is the highest of -503 mV in Example 8 and the lowest of -356 mV in Example 1. At the same time, the minimum Tafel slope is 64.35 mVdec in Example 1. -1 The maximum value is 99.64mV dec of Example 8 -1 The performance test results in Table 1 indicate that the lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in the present invention exhibits excellent HER performance in an alkaline medium consisting of 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution. The above test data indicate that Example 1 is the best embodiment of the present invention.

[0199] As can be seen from Table 2, 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution alkaline medium were used as electrolytes for detection. -2 At a potential of 500 mA cm, the electrochemical UOR performance of the lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared by the present invention is as high as 1.33 V in Example 10 and as low as 1.28 V in Example 1; -2 Under the potential of 1000mA cm, the electrochemical hydrogen evolution performance of the catalyst prepared by the present invention is the highest 1.49V of Example 10 and the lowest 1.40V of Example 1; -2 At the potential of , the electrochemical UOR performance of the catalyst prepared by the present invention is the highest 1.65V of Example 10 and the lowest 1.46V of Example 1. At the same time, the minimum Tafel slope is 41.42mV dec of Example 1. -1 The maximum value is 80.56mV dec of Example 10 -1 The performance test results in Table 2 indicate that the lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in the present invention exhibits excellent UOR performance in a 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution. Furthermore, the above test data indicate that Example 1 is the best example of the present invention.

[0200] The lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in this embodiment 1 and 20 wt.% of commercial Pt / C catalyst were detected by hydrogen evolution linear sweep voltammetry (LSV) in 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution, and the scanned curve data are shown in Figure 4 .

[0201] From Figure 4 It can be seen that the LSV curve proves the electrochemical performance of the catalyst prepared in this embodiment, and in combination with the data in Table 1, it can be known that at the same current density, the smaller the overpotential, the better the HER performance of the catalyst. At -10 mA cm -2 The overpotential of the catalyst prepared in this embodiment is close to that of the commercial Pt / C catalyst in the alkaline medium, which indicates that the HER electrochemical performance of the catalyst prepared in this embodiment is equivalent to that of the commercial Pt / C catalyst.

[0202] The lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in this embodiment 1 and 20 wt.% of commercial Pt / C catalyst were detected by Tafel slope in 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution, and the detected curve data are shown in Figure 5 .

[0203] The Tafel slope is obtained by formula change from LSV. At the same time, the Tafel slope represents the speed of reaction kinetics, Figure 5 In combination with the data in Table 1, it can be known that the smaller the Tafel slope value, the faster the reaction kinetics; the larger the Tafel slope value, the slower the reaction kinetics. In the alkaline medium of 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution, the Tafel slope of the catalyst prepared in this embodiment is close to that of the commercial Pt / C catalyst, which indicates that the reaction kinetics of the catalyst prepared in this embodiment is equivalent to that of the commercial Pt / C catalyst.

[0204] The lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in this embodiment 1 and 40 wt.% of commercial RuO2 / C catalyst were detected by hydrogen evolution linear sweep voltammetry (LSV) in 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution, and the scanned curve data are shown in Figure 6 .

[0205] Figure 6 The LSV curve can prove the electrochemical performance of the catalyst prepared in this embodiment, and in combination with the data in Table 2, it can be known that at the same current density, the smaller the potential, the better the UOR performance of the catalyst. At 10 mA cm -2At the potential, the overpotential of the catalyst prepared in the embodiment is close to that of the commercial RuO2 / C catalyst, indicating that the electrochemical performance of the catalyst prepared in the application is equivalent to that of the commercial RuO2 / C catalyst.

[0206] The lignin-derived carbon-alloy-metal oxide heterojunction catalyst prepared in Embodiment 1 and 40 wt.% of the commercial RuO2 / C catalyst were subjected to Tafel slope detection in a mixed solution of 1.0 mol / L potassium hydroxide and 0.5 mol / L urea, and the curve data of the detection are shown in FIG. 6. Figure 7 .

[0207] The Tafel slope is obtained by formula change from LSV. At the same time, the Tafel slope represents the speed of reaction kinetics, Figure 7 It can be known from the data in Table 2 that the smaller the Tafel slope value, the faster the reaction kinetics; the larger the Tafel slope value, the slower the reaction kinetics. In the alkaline medium of 1.0 mol / L potassium hydroxide and 0.5 mol / L urea solution, the Tafel slope of the catalyst prepared in the embodiment is close to that of the commercial RuO2 / C catalyst, indicating that the reaction kinetics of the catalyst prepared in the application is equivalent to that of the commercial RuO2 / C catalyst.

[0208] It should be noted that although the above embodiments have been described in the present text, the patent protection scope of the present application is not limited thereby. Therefore, based on the innovative idea of the present application, the changes and modifications made to the embodiments described in the present text, or the equivalent structure or equivalent process transformation made by using the content of the present application specification and drawings, directly or indirectly apply the above technical solutions to other related technical fields, are all included in the patent protection scope of the present application.

Claims

1. A method for preparing a lignin-derived carbon-alloy-metal oxide heterojunction catalyst, characterized in that: It includes the following steps: 1) dissolving metal salt A and metal salt B in an organic solvent to obtain a mixed solution C; The metal salt A is one or a mixture of two or more of the following: chromium salt, manganese salt, iron salt, nickel salt, vanadium salt, cobalt salt, tungsten salt, copper salt, zinc salt, or molybdenum salt; The metal salt B is one of the following: molybdenum salt, scandium salt, titanium salt, vanadium salt, chromium salt, zinc salt, gallium salt, germanium salt, strontium salt, yttrium salt, zirconium salt, niobium salt, cadmium salt, indium salt, tin salt, antimony salt, hafnium salt, tantalum salt, tungsten salt, rhenium salt, osmium salt, thallium salt, lead salt, bismuth salt, lanthanum salt, cerium salt, praseodymium salt, neodymium salt, samarium salt, europium salt, gadolinium salt, terbium salt, dysprosium salt, holmium salt, erbium salt, ytterbium salt or thulium salt; The metal salt A and metal salt B are different types of metal salts; 2) dissolving lignin in the mixed solution C to obtain a mixed solution D, then adding the mixed solution D and the pretreated carrier into a reactor for a solvothermal reaction at a temperature of 100-200° C. for a reaction time of 4-24 hours. After the reaction is completed, the mixture is cooled to room temperature, the reaction solution in the reactor is removed and filtered, and the filter cake is washed and dried to obtain a preliminary sample; The input mass ratio of the metal salt A, metal salt B, and lignin is 10-26.2:2:1-4; The ratio of the input mass of the metal salt A to the surface area of ​​the pretreated support is 1-4:9 mg / cm 2 ; 3) placing the preliminary sample prepared in step 2) in a calcination furnace, introducing a mixture of hydrogen and argon, wherein the volume fraction of hydrogen in the mixed gas is 10-50%, heating the sample to 400-1000° C. at a heating rate of 3-15° C. / min, and calcining the mixture at high temperature for 1-5 hours to obtain the lignin-derived carbon-alloy-metal oxide heterojunction catalyst.

2. The method for preparing a lignin-derived carbon-alloy-metal oxide heterojunction catalyst according to claim 1, characterized in that: The carrier in step 1) is a metal carrier or a non-metal carrier, and the metal carrier is one of the following: metal mesh, metal sheet, metal wire, metal foil, alloy mesh, alloy sheet, or alloy wire.

3. The method for preparing a lignin-derived carbon-alloy-metal oxide heterojunction catalyst according to claim 2, characterized in that: The metal mesh is one of the following: nickel mesh, cobalt mesh, copper mesh, iron mesh, titanium mesh; The alloy mesh is a nickel-iron mesh or a nickel-molybdenum mesh; The metal sheet is one of the following: nickel sheet, cobalt sheet, copper sheet, iron sheet, titanium sheet; The alloy sheet is one of the following: nickel-cobalt sheet, nickel-copper sheet, iron-copper sheet, nickel-iron sheet, stainless steel sheet, nickel-molybdenum sheet or nickel-chromium sheet; The metal wire is one of the following: nickel wire, cobalt wire, copper wire, iron wire, aluminum wire, titanium wire; The alloy wire is nickel-iron wire or nickel-molybdenum wire; The metal foil is one of the following: nickel foil, cobalt foil, copper foil, iron foil, zinc foil or titanium foil; The non-metallic carrier is one of the following: carbon black tubes, carbon nanotubes, carbon fiber sheets, activated carbon fiber sheets, carbon nanorods, graphene blocks, graphene oxide blocks, activated carbon blocks, porous carbon blocks, carbon cloth, carbon felt, glass fiber mesh, layered graphite, organic glass or expanded perlite.

4. The method for preparing a lignin-derived carbon-alloy-metal oxide heterojunction catalyst according to claim 1, characterized in that: In the step 3), after the preliminary sample is placed in a calcining furnace for calcination, two or more metal salts A are calcined to form an alloy, or one or more metal salts A are calcined with part of the metal salt B to form an alloy, and the formed alloy is a mixture of one or more of the following: NiCo, MoNi, NiFe, NiMn, NiCu, NiCr, NiZn, NiV, NiW, CuCo, CuZn, CuMo, CuFe, CuMn, CuV, CuW, FeCr, FeMn, FeCo, FeZn, FeV, FeW, CoMn, CoZn, CoMo, CoCr, CoV, CoW, NiCoCu, CoCrMo, NiCoMo, NiFeMo, NiMnMo, NiCrMo, NiCuMo, NiCoFe, NiCoZn, NiCoCr, NiCoMn, NiCoV, NiCoW; In the step 3), after the preliminary sample is placed in a calcination furnace for calcination, the metal salt B is calcined to form a metal oxide, the metal oxide forms a heterojunction and is loaded on a self-supporting carrier, and the formed metal oxide is one of the following: MoO2, Sc2O3, TiO2, V2O5, CrO3, ZnO, Ga2O3, GeO2, SrO, Y2O3, ZrO2, Nb2O5, CdO, In2O3, SnO2, Sb2O5, HfO2, Ta2O5, WO2, ReO3, OsO2, Tl2O3, Pb3O4, Bi2O3, La2O3, CeO2, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3.

5. The method for preparing a lignin-derived carbon-alloy-metal oxide heterojunction catalyst according to claim 1, characterized in that: The carrier pretreatment method is as follows: the untreated carrier is washed with anhydrous ethanol, 1.0 mol / L hydrochloric acid and deionized water in sequence, each washing is performed 3 times, and each washing time is 20-30 minutes.

6. The method for preparing a lignin-derived carbon-alloy-metal oxide heterojunction catalyst according to claim 1, characterized in that: The solvent added in step 1) is one of the following: ethanol, ethylene glycol, methanol, isopropanol, glycerol, n-butanol, N,N-dimethylformamide, oleylamine, oleic acid, polyethylene glycol, toluene, acetonitrile, N,N-dimethylacetamide, dimethyl sulfoxide, pyridine, pyrrole, urea, aniline, N-methylaniline, N,N-dimethylaniline, N-ethylaniline, N,N-diethylaniline, diphenylamine, aniline hydrochloride, dioxydimethylpurine, phenylalanine, 2-hydroxypyridine, 2-aminopyridine, 2,6- Diaminopyridine, 2-methylpyridine, 3-aminopyridine, 4-methylpyridine, pentachloropyridine, 3-chloropyridine, 3-fluoropyridine, 3-bromopyridine, 2,3-diaminopyridine, 2-amino-3-chloropyridine, 2-pyrrolidone, 2-pyrrolecarboxylic acid, 3-acetyl-2,4-dimethylpyrrole, hydroxyethylpyrrolidone, 2-acetylpyrrole, 1-methylpyrrole, tetrahydropyrrole, ethyl pyrrole-2-carboxylate, 2,4-dimethylpyrrole, 4-acetylpyridine, 2-acetylpyrrole, N-methylpyrrole or deionized water.

7. The method for preparing a lignin-derived carbon-alloy-metal oxide heterojunction catalyst according to claim 1, characterized in that: The metal chromium salt in the metal salt A in step 1) is one of the following: sodium chromate, potassium chromate, lead chromate, ammonium chromate, sodium dichromate, chromic anhydride, potassium dichromate, chromium oxide green, basic chromium sulfate; The metal manganese salt in the metal salt A in step 1) is one of the following: manganese chloride, manganese sulfate, manganese nitrate, manganese carbonate, manganese acetate, manganese oxalate, manganese phosphate, manganese bromide, manganese iodide, manganese fluoride, manganese perchlorate, manganese citrate, manganous sulfate, manganous acetate, manganous oxalate, manganous hydrogen phosphate, manganese pyrophosphate, manganese silicate, manganese metasilicate; The metal iron salt in the metal salt A in step 1) is one of the following: ferric sulfate, ferric chloride, ferric nitrate, ferric carbonate, ferrous sulfate, ferrous chloride, ferrous carbonate, ferric bromide, ferric perchlorate, or ferric dihydrogen phosphate; The metal vanadium salt in the metal salt A in step 1) is one of the following: ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadium chloride, vanadium oxide, vanadium tetrachloride, sodium vanadate, vanadium acetylacetonate, triisopropoxide vanadyl, acetylacetonate vanadyl, triisopropoxy vanadium oxide, and diacetylacetonate vanadium oxide; The metal cobalt salt in the metal salt A in step 1) is one of the following: cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt acetate, cobalt oxalate, cobalt phosphate, cobalt bromide, cobalt iodide, cobalt sulfide, cobalt fluoride, cobalt perchlorate, cobalt citrate, cobalt stearate, cobalt laurate, cobalt benzoate, ammonium cobalt chloride, ammonium cobalt sulfate, ammonium cobalt nitrate, cobalt hydrogen phosphate, and cobaltous acetate; The metal tungsten salt in the metal salt A in step 1) is one of the following: ammonium metatungstate, ammonium tungstate, potassium tungstate, sodium tungstate, phosphotungstic acid, sodium phosphotungstate, tungstosilicic acid, tungsten hexachloride, tungsten hexacarbonyl, tungsten isopropoxide; The metal nickel salt in the metal salt A in step 1) is one of the following: nickel chloride, nickel acetylacetonate, nickel acetylacetonate, nickel acetate, nickel bromide, nickel iodide, nickel sulfate, nickel nitrate, nickel sulfate, nickel hypophosphite, nickel nitrate, nickel sulfamate, basic nickel carbonate, nickel formate, nickelocene, bis(triphenylphosphine)nickel bromide, bis(triphenylphosphine)nickel chloride; The metal copper salt in the metal salt A in step 1) is one of the following: copper sulfate, copper chloride, copper carbonate, copper acetate, basic copper carbonate, copper gluconate, copper acetate, copper citrate; The metal zinc salt in the metal salt A in step 1) is one of the following: zinc cyclohexanoate, zinc acetate, zinc acetate, methyl zinc, zinc oxide, zinc glycinate, zinc orotate, zinc picolinate, zinc gluconate, zinc sulfate; The metal molybdenum salt in the metal salt A in step 1) is one of the following: molybdic acid, ammonium molybdate tetrahydrate, ammonium heptamolybdate, ammonium dimolybdate, sodium molybdate, phosphomolybdic acid, ammonium phosphomolybdate, sodium phosphomolybdate, molybdenum chloride, lithium molybdate, potassium molybdenum hexacarbonyl, molybdenum acetylacetonate, and molybdenum isopropoxide; The metal molybdenum salt in the metal salt B in step 1) is one of the following: molybdic acid, ammonium molybdate tetrahydrate, ammonium heptamolybdate, ammonium dimolybdate, sodium molybdate, phosphomolybdic acid, ammonium phosphomolybdate, sodium phosphomolybdate, molybdenum chloride, lithium molybdate, potassium molybdate, hexacarbonyl molybdenum, molybdenum acetylacetonate, and molybdenum isopropoxide; The metal scandium salt in the metal salt B in step 1) is one of the following: scandium nitrate, scandium chloride, scandium sulfate, scandium acetate, scandium phosphate, scandium fluoride, scandium oxalate, and scandium carbonate; The metal titanium salt in the metal salt B in step 1) is one of the following: titanic acid, titanium tetrachloride, titanium trichloride, titanium orthosulfate, titanyl sulfate, orthotitanic acid, sodium titanosilicate; The metal vanadium salt in the metal salt B in step 1) is one of the following: ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadium chloride, vanadium oxide, vanadium tetrachloride, sodium vanadate, vanadium acetylacetonate, triisopropoxide vanadyl, acetylacetonate vanadyl, triisopropoxy vanadium oxide, and diacetylacetonate vanadium oxide; The metal chromium salt in the metal salt B in step 1) is one of the following: sodium chromate, potassium chromate, lead chromate, ammonium chromate, sodium dichromate, chromic anhydride, potassium dichromate, chromium oxide green, basic chromium sulfate; The metal zinc salt in the metal salt B in step 1) is one of the following: zinc cyclohexanoate, zinc acetate, zinc acetate, methyl zinc, zinc oxide, zinc glycinate, zinc orotate, zinc picolinate, zinc gluconate, zinc sulfate; The metal gallium salt in the metal salt B in step 1) is one of the following: gallium nitrate, gallium sulfate, gallium chloride, gallium fluoride, gallium hydroxide, and gallium acetate; The metal germanium salt in the metal salt B in step 1) is one of the following: germanate, metagermanate, digermanate, tetragermanate; The metal strontium salt in the metal salt B in step 1) is one of the following: strontium sulfate, strontium chloride, strontium nitrate, strontium carbonate, strontium hydroxide, and strontium acetate; The metal yttrium salt in the metal salt B in step 1) is one of the following: yttrium chloride, yttrium nitrate, yttrium sulfate, yttrium acetate, yttrium oxalate, and yttrium fluoride; The metal zirconium salt in the metal salt B in step 1) is one of the following: zirconium chloride, zirconium sulfate, zirconium carbonate, zirconium oxychloride, zirconium nitrate, zirconium acetate, and zirconium fluoride; The metal niobium salt in the metal salt B in step 1) is one of the following: niobium chloride, niobium fluoride, niobium pentachloride, niobium oxide, and niobium oxalate; The metal cadmium salt in the metal salt B in step 1) is one of the following: cadmium sulfate, cadmium chloride, cadmium nitrate, cadmium acetate, cadmium carbonate, or cadmium iodide; The metal indium salt in the metal salt B in step 1) is one of the following: indium chloride, indium nitrate, indium sulfate, indium iodide, indium acetate; The metal tin salt in the metal salt B in step 1) is one of the following: tin chloride, tin sulfate, sodium stannate, tin fluoride, tin carbonate, tin acetate; The metal antimony salt in the metal salt B in step 1) is one of the following: antimony chloride, antimony trioxide, potassium antimony tartrate, and antimony acetate; The metal hafnium salt in the metal salt B in step 1) is one of the following: hafnium chloride, hafnium fluoride, hafnium sulfate, hafnium nitrate, hafnium acetate, and hafnium oxide; The metal tantalum salt in the metal salt B in step 1) is one of the following: tantalum chloride, potassium heptafluorotantalate, tantalum methanol, tantalum ethoxide, tantalum propoxide, tantalum butoxide, tantalum isobutoxide; The metal tungsten salt in the metal salt B in step 1) is one of the following: ammonium metatungstate, ammonium tungstate, potassium tungstate, sodium tungstate, phosphotungstic acid, sodium phosphotungstate, tungstosilicic acid, tungsten hexachloride, tungsten hexacarbonyl, tungsten isopropoxide; The metal rhenium salt in the metal salt B in step 1) is one of the following: rhenium heptoxide, rhenium dioxide, rhenium trioxide, rhenium disulfide, rhenium diboride, rhenium tetrafluoride, rhenium pentafluoride, and perrhenic acid; The metal osmium salt in the metal salt B in step 1) is one of the following: osmium tetroxide, osmium dioxide, sodium hexachloroosmate, osmium disulfide, osmium ditelluride; The metal lead salt in the metal salt B in step 1) is one of the following: lead nitrate, lead acetate, lead chloride, lead arsenate, lead oxide; The metal bismuth salt in the metal salt B in step 1) is one of the following: bismuth nitrate, bismuth chloride, and bismuth sulfate; The metal lanthanum salt in the metal salt B in step 1) is one of the following: lanthanum nitrate, lanthanum chloride, lanthanum acetate, and lanthanum sulfate; The metal cerium salt in the metal salt B in step 1) is one of the following: cerium nitrate, cerium sulfate, cerium chloride, and cerium oxalate; The metal praseodymium salt in the metal salt B in step 1) is one of the following: praseodymium chloride, praseodymium oxide, praseodymium nitrate, and praseodymium sulfate; The metal neodymium salt in the metal salt B in step 1) is one of the following: neodymium nitrate, neodymium chloride, neodymium sulfate, and neodymium acetate; The metal samarium salt in the metal salt B in step 1) is one of the following: samarium nitrate, samarium carbonate; The metal europium salt in the metal salt B in step 1) is one of the following: europium fluoride, europium nitrate; The metal gadolinium salt in the metal salt B in step 1) is one of the following: gadolinium sulfate, gadolinium nitrate; The metal terbium salt in the metal salt B in step 1) is one of the following: terbium nitrate, terbium chloride, or terbium sulfate; The metal dysprosium salt in the metal salt B in step 1) is one of the following: dysprosium nitrate, dysprosium sulfate; The metal holmium salt in the metal salt B in step 1) is one of the following: holmium chloride, holmium sulfate; The metal erbium salt in the metal salt B in step 1) is one of the following: one of erbium nitrate, erbium chloride, and erbium sulfate; The metal thulium salt in the metal salt B in step 1) is one of the following: thulium chloride, thulium nitrate; The metal ytterbium salt in the metal salt B in step 1) is one of the following: ytterbium chloride and ytterbium sulfate.

8. The method for preparing a lignin-derived carbon-alloy-metal oxide heterojunction catalyst according to claim 1, characterized in that: The lignin in step 2) is one of the following: alkaline lignin, dealkalized lignin, sodium lignin sulfonate, sulfate lignin, hydrolyzed lignin, organosolv lignin, pyrolyzed lignin, enzymatic lignin, carboxymethylated lignin, aminated lignin, phosphorylated lignin, carboxylated lignin, sulfonated lignin or sulfurized lignin.

9. The method for preparing a lignin-derived carbon-alloy-metal oxide heterojunction catalyst according to claim 1, characterized in that: In the step 2), the mixed solution D is first subjected to ultrasonic stirring and dispersion to be completely dissolved to obtain a mixed suspension liquid, and then the mixed suspension liquid and the pretreated carrier are added together into a reactor to carry out a solvothermal reaction.

10. A lignin-derived carbon-alloy-metal oxide heterojunction catalyst, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 9.

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