Wood-derived carbon supported metal oxide-alloy heterogeneous catalysts, methods of making and using the same

Abstract

This invention discloses a method for preparing a wood-derived carbon-supported metal oxide-alloy heterojunction catalyst, comprising the following steps: Step 1, alkaline pretreatment and delignification of wood chips; Step 2, atmospheric pressure impregnation with a single metal salt; Step 3, high-temperature carbonization; Step 4, preparation of an intermediate loaded with a bimetallic component; Step 5, annealing to obtain the wood-derived carbon-supported metal oxide-alloy heterojunction catalyst. This wood-derived carbon-supported metal oxide-alloy heterojunction catalyst can be directly used as a bifunctional catalyst for both cathode and anode in an urea-assisted hydrogen production system. It can be applied in alkaline electrolysis systems containing urea wastewater to achieve efficient hydrogen evolution at the cathode and efficient urea oxidation at the anode, making it suitable for low-energy hydrogen production and resource-based treatment of industrial / domestic urea wastewater. Furthermore, the overall preparation process is simple, with low raw material costs, outstanding catalytic performance, and high stability, possessing extremely high industrial application value and market prospects.

Description

Technical Field

[0001] This invention relates to the field of electrocatalyst technology, and in particular to a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, its preparation method, and its application. Background Technology

[0002] To actively address the challenges of global warming, promoting the transformation of the energy structure towards cleaner and renewable energy has become a global consensus. Hydrogen energy, as a clean energy source with high calorific value and pollution-free combustion products, is considered a core carrier for replacing traditional fossil fuels and building a future low-carbon energy system. Its large-scale development and utilization are of great significance to energy transformation. Water electrolysis is one of the most promising hydrogen production pathways, but traditional water electrolysis suffers from slow kinetics of the oxygen evolution reaction (OER), high electrolysis energy consumption, and safety hazards related to hydrogen-oxygen mixing. Urea electrolysis-assisted hydrogen production technology, which replaces OER with urea oxidation reaction (UOR), reduces the theoretical potential of the anolyte reaction from 1.23 V to 0.37 V, significantly reducing electrolysis energy consumption while achieving resource recovery of urea-containing wastewater. This technology combines environmental protection and energy conservation, making it a research hotspot in the field of low-energy hydrogen production.

[0003] Despite the significant advantages of urea electrolysis-assisted hydrogen production technology, it still faces numerous technical challenges in practical applications. Firstly, the high energy barrier for breaking the C–N bonds in urea molecules leads to slow kinetics and low efficiency in the urea oxidation reaction. Secondly, intermediate byproducts are easily generated during the reaction, which readily adsorb onto the active sites of the catalyst, causing catalyst poisoning and resulting in a significant decrease in catalyst activity and long-term stability. Furthermore, the complex impurities present in actual urea-containing wastewater can interfere with the reaction process, further reducing electrolysis efficiency and catalyst durability, severely limiting the practical application of this technology.

[0004] Catalysts are the core of urea-assisted hydrogen production technology, and their performance directly determines the energy consumption and efficiency of the electrolysis process. Currently disclosed wood-derived carbon-based transition metal catalysts (such as wood-derived carbon self-supporting transition metal core-shell hydrogen evolution catalysts) have a core structure of a single transition metal core-alloy shell heterojunction, with all active sites being metal / alloy phases. They can only optimize the adsorption / desorption behavior of H* through electronic structure regulation, making them cathodic hydrogen evolution reaction (HER) specific catalysts and unsuitable for anodic UOR reactions. Firstly, these catalysts lack specific active site structures for urea activation and C-N bond breaking; if forcibly applied to the anode, the catalytic efficiency is extremely low. Secondly, their metal / alloy phases are easily corroded and deactivated in the anodic oxidation environment, lacking basic adaptability to anodic conditions. Meanwhile, at the electrode structure design level, traditional powdered transition metal catalysts usually need to be coated with binders on the surface of rigid substrates (such as metal foam, carbon rods, titanium sheets, etc.) to achieve electrode function. This method is not only complex and increases the preparation cost, but also easily leads to the catalyst active sites being buried by binders and the active particles agglomerating, thereby reducing the catalyst conductivity, active site utilization rate and electrode mass transfer efficiency, ultimately restricting the full realization of catalytic performance.

[0005] Natural wood, as a widely available, environmentally friendly, and structurally unique biomass material, possesses natural self-supporting properties, a three-dimensional interconnected pore structure, a high specific surface area, and abundant oxygen-containing functional groups on its surface. This makes it an ideal carrier for constructing high-performance, low-cost integrated self-supporting electrodes. Its three-dimensional pores can optimize electrolyte diffusion and reactive gas desorption processes, improving mass transfer efficiency; the oxygen-containing functional groups on its surface can provide stable anchoring points for transition metal active centers, effectively inhibiting the aggregation of active components. However, existing hydrogen evolution catalysts based on wood-derived carbon have certain limitations in their preparation processes: the lack of an alkaline impregnation pretreatment step and the use of multiple vacuum impregnation and two-step delignification processes only allow for single loading of the metal / alloy phase, failing to form a multiphase heterojunction suitable for both anion / anode dual catalysis. Furthermore, the process is cumbersome, requires advanced equipment, and is difficult to scale up for industrial production. Furthermore, existing catalysts can only achieve HER catalysis in pure alkaline / neutral pure water electrolytes. In actual wastewater electrolytes containing urea and impurities, due to the lack of adsorption selectivity at the active sites, competitive adsorption between impurities and reaction intermediates easily occurs, leading to a significant decrease in catalytic performance and extremely poor adaptability to actual operating conditions.

[0006] In summary, existing technologies lack bifunctional catalysts suitable for both anode and cathode catalysis in urea electrolysis systems. Furthermore, simply extending existing cathode HER catalysts to anode applications cannot solve these problems—such extensions are inherently limited. The structural design, active site characteristics, and preparation processes of existing cathode catalysts are optimized only for the cathode HER reaction, neglecting the core requirements of the anode UOR reaction, thus failing to address the challenges of anode catalysis activity and stability. Therefore, there is an urgent need in the field to develop a wood-derived carbon-based catalyst with a scientifically designed structure, high efficiency in both cathode and anode functions, a simple preparation process, and strong adaptability to practical operating conditions. This invention presents an innovative solution addressing the multiple core deficiencies of the existing technologies. Summary of the Invention

[0007] Therefore, in order to overcome the core defect that existing transition metal catalysts can only achieve single cathode HER catalysis and cannot be adapted to anode UOR reaction, and to solve the fundamental problem of "simply extending existing cathode materials to anode applications", this invention provides a highly efficient bifunctional catalyst that can serve as both cathode and anode in the urea electrolysis system. It also features a wood-derived carbon-supported metal oxide-alloy heterojunction catalyst with simple preparation process, low raw material cost, strong adaptability to actual working conditions, and high catalytic stability, as well as its preparation method and application.

[0008] To achieve the above objectives, the inventors provide a method for preparing a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, which includes the following steps:

[0009] Step 1: Alkali Pretreatment and Delignification of Wood Chips: First, immerse the wood chips in an alkaline solution. After alkali immersion, wash the wood chips with deionized water until neutral and dry them. Then, perform delignification treatment on the alkali-immersed wood chips. After the reaction is complete, remove the wood chips, wash and dry them to obtain pretreated wood chips.

[0010] Step 2: Single metal salt impregnation at atmospheric pressure: Dissolve metal salt A in solvent A to prepare metal salt A solution. Immerse the pretreated wood chips obtained in Step 1 directly into the metal salt A solution and let them stand under atmospheric pressure for 4–10 hours. After removal, wash and dry to obtain single metal-loaded wood chips. The metal salt A is one of nickel salt, cobalt salt, molybdenum salt, copper salt, iron salt, and manganese salt.

[0011] Step 3: High-temperature carbonization: The single-metal supported wood chips obtained in Step 2 are placed in a tube furnace and calcined at 600–1000 °C for 1–4 hours under a nitrogen atmosphere to obtain carbon-based precursor sample B.

[0012] Step 4: Dissolve two different metal salts D and E in solvent A to prepare a mixed metal salt solution; add the sample B obtained in step 3 to the mixed metal salt solution, stir evenly, and then transfer to a reaction vessel for a solvothermal reaction at 80–200 °C for 6–10 hours; after the reaction is completed, cool, wash, and dry to obtain an intermediate loaded with bimetallic components;

[0013] Step 5: Annealing: The intermediate obtained in Step 4 is placed in a mixed atmosphere of hydrogen and argon and calcined at 400–800 °C for 2–6 hours to generate a metal oxide-alloy multiphase heterojunction in situ, thus obtaining the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst.

[0014] This invention prepares a wood-derived carbon-supported metal oxide-alloy heterojunction catalyst using the above method. The heterojunction is constructed in situ using metal oxides and metal alloys and supported on a wood-derived carbon substrate. The catalyst contains catalytically active metal elements and catalytically active non-metal elements from the wood-derived carbon. The metal elements are at least two selected from Ni, Co, Mo, Cu, Fe, and Mn, and the non-metal elements are C and O. C and O are among the core active components involved in catalysis, synergistically achieving dual-site specific catalysis with the metal phase.

[0015] Metallic and non-metallic active components are uniformly dispersed within and on the surface of the wood-derived carbon framework, forming cathode-specific HER active sites and anode-specific UOR active sites. Metallic alloy phases (such as NiCo alloys) and the carbon in wood-derived carbon synergistically constitute the cathode-specific HER active sites, adapting to the electron transfer and intermediate transformation patterns of the cathode hydrogen evolution reaction. C accelerates electron transport through high conductivity and can electronically couple with the metallic alloy, thereby optimizing H2O. * Adsorption / conversion.

[0016] In metal oxide phases (such as Ni-CoMoO4 molybdate), lattice O and metal cations synergistically constitute the anodic UOR-specific active sites. Lattice O and metal cations synergistically activate the CN bond of urea, forming a specific active center adapted to the activation and CN bond breaking of urea molecules. Its surface electron distribution and adsorption characteristics are specifically optimized for intermediates in the urea oxidation reaction. At the same time, lattice O and metal cations synergistically regulate the surface adsorption characteristics to achieve selective conversion of urea oxidation intermediates.

[0017] Furthermore, the wood chips in step 1 are one of pine, fir, poplar, elm, birch, camphor, or eucalyptus.

[0018] Further, step 1 specifically involves: placing the wood chips in a 0.5–2 mol / L sodium hydroxide solution and immersing them at a constant temperature of 60–90 °C for 2–5 h to induce swelling and degreasing; after immersion, washing the wood chips with deionized water until neutral and drying them; then placing the immersed wood chips in a mixture of water, glacial acetic acid, and sodium chlorite, with a mass ratio of wood chips to initially added water, glacial acetic acid, and sodium chlorite of 2:200:1:3, and reacting at 70–85 °C with stirring for 2–5 h to perform delignification treatment; after the reaction, removing the wood chips, washing, and drying them to obtain pretreated wood chips.

[0019] Through the aforementioned two-step pretreatment of alkaline leaching and delignification, lignin, oils, and some hemicellulose within natural wood can be effectively removed, resulting in sufficient swelling and loosening of the wood structure. This not only opens up the multi-level pores within the wood, improving the penetration and loading uniformity of subsequent metal salt precursors, but also purifies the cellulose-based carbon skeleton, reducing amorphous impurities and agglomeration during high-temperature carbonization. Simultaneously, alkaline leaching pre-activates the wood substrate, introducing abundant surface defects and oxygen-containing functional groups, providing sufficient sites for the anchoring of subsequent metal active components. This facilitates the formation of a uniformly dispersed and firmly bonded metal oxide-alloy heterogeneous structure, ultimately enhancing the catalyst's conductivity, structural stability, and electrocatalytic activity.

[0020] Furthermore, in step 2, solvent A is one of water, methanol, ethanol, isopropanol, n-butanol, cyclohexane, diethyl ether, and ethyl acetate.

[0021] Further, the nickel salts include nickel nitrate, nickel sulfate, nickel acetate, nickel chloride, nickel bromide, nickel iodide, nickel 2-ethylhexanoate, nickel acetylacetonate, and ammonium nickel sulfate, etc.; the cobalt salts include cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt acetate, cobalt oxalate, cobalt borylate, cobalt naphthenate, cobalt bromide, and cobalt sulfide, etc.; the molybdenum salts include ammonium molybdate, sodium molybdate, potassium molybdate, molybdenum chloride, molybdenum nitrate, molybdenum acetate, molybdenum sulfate, and ammonium phosphomolybdate, etc.; the copper salts include copper chloride, copper sulfate, copper nitrate, copper acetate, copper carbonate, copper oxalate, copper bromide, copper iodide, and copper acetylacetonate, etc.; the iron salts include ferric chloride, ferric sulfate, ferric nitrate, ferric acetate, ferric oxalate, ferric bromide, ferric iodide, ferrous sulfate, ferrous nitrate, and ferrous chloride, etc.; and the manganese salts include manganese chloride, manganese sulfate, manganese nitrate, manganese acetate, manganese carbonate, manganese oxalate, manganese bromide, manganese iodide, and manganese acetylacetonate, etc.

[0022] Furthermore, in step 2, the concentration of the metal salt A solution is 0.5–5 mmol / mL.

[0023] Furthermore, in step 4, the concentrations of both metal salt D and metal salt E are 0.5–5 mmol / mL.

[0024] Furthermore, the metal salts D and E are each selected from any one of nickel salts, cobalt salts, molybdenum salts, copper salts, iron salts, and manganese salts, and are all different from the type of metal salt A. Metal salts D and E may also be different, and the two may be mixed in any proportion.

[0025] Furthermore, in step 5, the calcination heating rate is 2–20 °C / min, and the volume fraction of hydrogen in the mixed gas is 5%–20%.

[0026] The present invention also discloses a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, which is prepared by the above-described preparation method.

[0027] This invention also discloses the application of a wood-derived carbon-supported metal oxide-alloy heterojunction catalyst, which is used as a catalyst in the electrocatalytic hydrogen evolution reaction and urea oxidation reaction.

[0028] The above technical solution has the following advantages, unlike existing technologies:

[0029] The wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst prepared in this invention is not simply an extension of existing cathode HER catalysts to anode applications. Instead, it solves the core technical challenge of simultaneously adapting a single material to both cathode HER and anode UOR reactions from the perspectives of principle, structure, and preparation process through the specialized design of cathode / anode active sites, the directional construction of multiphase heterojunctions, the differentiated regulation of electronic structure and adsorption characteristics, and systematic innovation in the preparation process. The specific analysis is as follows:

[0030] (1) Site differentiation, breaking through the single cathode limitation

[0031] Existing core-shell hydrogen evolution catalysts all have metal / alloy phase active sites, suitable only for cathode HER reactions and lacking the structural basis for anodic UOR catalysis. This invention does not simply expand the application scenarios based on existing active sites, but rather forms two functionally independent and characteristically compatible exclusive active sites through the directional construction of a metal oxide-alloy heterostructure: the metal alloy phase precisely controls the adsorption free energy of H*, providing a highly active core site for cathode HER; the metal oxide phase, through the synergistic effect of lattice oxygen and metal cations, forms exclusive active centers for urea activation and CN bond breaking, providing a highly active core site for anode UOR. These two sites are tightly coupled and do not interfere with each other, theoretically achieving highly efficient catalysis of a single material as both anode and cathode. In a 1.0 mol / L KOH electrolyte containing 0.5 mol / L urea, the HER reaction efficiency is -10 mA / cm². 2Overpotential ≤ 68 mV, UOR response 300 mA / cm 2 With an overpotential of <1.38 V, it is directly compatible with urea electrolysis-assisted hydrogen production systems, representing a simple functional extension beyond existing technologies.

[0032] (2) Technological innovation to construct a dual-active-site structure

[0033] This invention features a fundamentally innovative process designed around the construction of bifunctional active sites: alkaline impregnation pretreatment fully opens the pores of the wood, providing a structural basis for the stratified loading of multiphase components; the stepwise process of single-metal impregnation-carbonization-bimetallic solvothermal treatment enables the stratified construction and precise coupling of dedicated active sites for the cathode (HER) and anode (UOR); and atmospheric pressure static impregnation eliminates the need for vacuum / ultrasonic equipment, simplifying the process and reducing energy consumption. This entire process is not a simple adjustment to existing processes, but rather a tailor-made design for bifunctional catalysis, ensuring the successful formation of multiphase heterojunctions and dedicated active sites.

[0034] (3) Adapting to operating conditions, solving the essential problems of anode application

[0035] Existing cathode catalysts suffer from two fundamental drawbacks in anode applications: the lack of dedicated urea oxidation sites and the susceptibility of the metal / alloy phase to corrosion in the anodic oxidation environment. This invention's catalyst achieves synergistic adaptation between the anode and cathode for practical operating conditions: the metal oxide phase provides excellent corrosion resistance to the anode and exhibits high adsorption selectivity for urea molecules, preferentially adsorbing urea in urea wastewater containing impurities and avoiding competitive adsorption by impurities; the metal alloy phase maintains stable hydrogen evolution activity in the cathode reduction environment, while the three-dimensional pores of the wood facilitate rapid desorption of H2, N2, and CO2, preventing performance degradation due to bubble adhesion. Simultaneously, replacing OER with UOR at the anode reduces the theoretical potential from 1.23 V to 0.37 V, and synergizes with the efficient HER at the cathode, significantly reducing electrolysis energy consumption. This catalyst offers the dual value of low-energy hydrogen production and urea wastewater resource treatment, meeting the needs of practical industrial applications.

[0036] In summary, the wood-derived carbon-supported metal oxide-alloy heterojunction catalyst of this invention can be directly used as a bifunctional catalyst for both the cathode and anode in an urea-assisted hydrogen production system. It can be applied in alkaline electrolysis systems containing urea wastewater to achieve efficient hydrogen evolution at the cathode and efficient urea oxidation at the anode. This catalyst is suitable for low-energy hydrogen production and the resource-based treatment of industrial / domestic urea wastewater. Furthermore, the overall preparation process is simple, with low raw material costs, outstanding catalytic performance, and high stability, demonstrating significant industrial application value and market potential. Attached Figure Description

[0037] Figure 1 These are field emission scanning electron microscope (SEM) images of different sizes of the wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy heterojunction catalyst prepared in Example 1 of this invention.

[0038] Figure 2 These are transmission electron microscope (TEM) images at different magnifications of the wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy heterojunction catalyst prepared in Example 1 of this invention.

[0039] Figure 3 The energy dispersive spectroscopy (EDS) spectrum of the wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy heterojunction catalyst prepared in Example 1 of the present invention was obtained by X-ray energy dispersive spectroscopy.

[0040] Figure 4 The X-ray diffraction (XRD) pattern of the wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy multiphase heterojunction catalyst prepared in Example 1 of the present invention.

[0041] Figure 5 The Raman spectrum of the wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy heterojunction catalyst prepared in Example 1 of this invention is shown.

[0042] Figure 6 The polarization curves of the hydrogen evolution reaction of the catalysts prepared in Example 1 and Comparative Examples 1-3 in a 1.0 mol / L potassium hydroxide solution containing 0.5 mol / L urea are shown. Detailed Implementation

[0043] To explain in detail the technical content, structural features, objectives, and effects of the technical solution, the following description is provided in conjunction with specific embodiments and accompanying drawings.

[0044] The specific embodiments are described in detail below with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Unless otherwise specified, the raw materials and reagents used in the embodiments are commercially available.

[0045] Example 1

[0046] A method for preparing a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, comprising the following steps:

[0047] (1) Alkali soaking pretreatment and single-step delignification of wood chips: Pine wood chips were placed in a 1 mol / L sodium hydroxide solution and soaked at a constant temperature of 75 °C for 3 h to perform swelling and degreasing treatment; after the alkali soaking, the chips were washed with deionized water until neutral and dried. The alkali-soaked wood chips were then transferred to a mixed solution of water, glacial acetic acid and sodium chlorite. The mass ratio of wood chips to the initially added water, glacial acetic acid and sodium chlorite was 2:200:1:3. The single-step delignification reaction was carried out at 75 °C under stirring for 3 h; after the reaction, the wood chips were taken out, washed and dried to obtain pretreated wood chips.

[0048] (2) Single metal salt impregnation at atmospheric pressure: Nickel nitrate was dissolved in deionized water to prepare a metal salt A solution with a concentration of 1 mmol / mL; the pretreated wood chips obtained in step (1) were immersed in the metal salt A solution and impregnated at atmospheric pressure for 4 h; after removal, they were washed and dried to obtain wood chips loaded with single metal nickel.

[0049] (3) High temperature carbonization: The wood chips obtained in step (2) are placed in a tube furnace and heated to 800 ℃ at 5 ℃ / min under a nitrogen atmosphere. The temperature is held for 2 h and then naturally cooled to obtain carbon-based precursor sample B.

[0050] (4) Bimetallic solvothermal reaction: Cobalt nitrate and ammonium molybdate were dissolved in deionized water to prepare mixed metal salt solutions with a concentration of 2 mmol / mL; sample B was added to the solution, stirred evenly, and then transferred to a reaction vessel for solvothermal reaction at 180 °C for 8 h; after cooling to room temperature, the solution was washed and dried to obtain the intermediate.

[0051] (5) Calcination in reducing atmosphere: The intermediate is placed in a hydrogen / argon mixed atmosphere with a hydrogen gas fraction of 5%, and the temperature is increased to 500 °C at 5 °C / min. The temperature is held for 2 h and then naturally cooled to obtain a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst (NiCo@Ni–CoMoO4 / CWC).

[0052] The wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy multiphase heterojunction catalyst prepared in this embodiment was subjected to field emission scanning electron microscopy (SEM). SEM images of different sizes are shown below. Figure 1 .in, Figure 1 (a) is a SEM image of the wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy heterojunction catalyst prepared in this example at 2 μm. Figure 1 (b) is a SEM image of the wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy heterojunction catalyst prepared in this embodiment at 500 nm.

[0053] The wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy heterojunction catalyst prepared in this embodiment was subjected to transmission electron microscopy (TEM) scanning. TEM images at different magnifications are shown below. Figure 2 .in, Figure 2 (a) is a TEM scan at 100 nm. Figure 2 (b) is a TEM scan at 20 nm. Figure 2 (c) is a TEM scan at 10 nm.

[0054] The wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy multiphase heterojunction catalyst prepared in this embodiment was scanned by X-ray energy dispersive spectroscopy (EDS). The obtained EDS spectrum is shown below. Figure 3 .

[0055] The wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy multiphase heterojunction catalyst prepared in this embodiment was subjected to X-ray diffraction (XRD) scanning. The obtained XRD pattern is shown in the figure. Figure 4 .

[0056] The wood-derived carbon-supported molybdate oxide-nickel-cobalt alloy heterojunction catalyst prepared in this embodiment was subjected to Raman scattering spectroscopy. The obtained Raman spectrum is shown below. Figure 5 .

[0057] Example 2

[0058] A method for preparing a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, comprising the following steps:

[0059] (1) Alkali soaking pretreatment and single-step delignification of wood chips: Poplar wood chips were placed in a 0.5 mol / L sodium hydroxide solution and soaked at a constant temperature of 90 ℃ for 2 h to perform swelling and degreasing treatment; after the alkali soaking, the chips were washed with deionized water until neutral and dried. The alkali-soaked wood chips were then transferred to a mixed solution of water, glacial acetic acid and sodium chlorite. The mass ratio of wood chips to the initially added water, glacial acetic acid and sodium chlorite was 2:200:1:3. The single-step delignification reaction was carried out at 75 ℃ under stirring for 5 h; after the reaction, the wood chips were taken out, washed and dried to obtain pretreated wood chips.

[0060] (2) Single metal salt impregnation at atmospheric pressure: Nickel nitrate was dissolved in deionized water to prepare a metal salt A solution with a concentration of 1 mmol / mL; the pretreated wood chips obtained in step (1) were immersed in the metal salt A solution and impregnated at atmospheric pressure for 4 h; after removal, they were washed and dried to obtain wood chips loaded with single metal nickel.

[0061] (3) High temperature carbonization: The wood chips obtained in step (2) are placed in a tube furnace and heated to 800 ℃ at 5 ℃ / min under a nitrogen atmosphere. The temperature is held for 2 h and then naturally cooled to obtain carbon-based precursor sample B.

[0062] (4) Bimetallic solvothermal reaction: Cobalt nitrate and ammonium molybdate were dissolved in deionized water to prepare a mixed metal salt solution with a concentration of 1 mmol / mL; sample B was added to the solution, stirred evenly, and then transferred to a reaction vessel for solvothermal reaction at 180 °C for 8 h; after cooling to room temperature, the solution was washed and dried to obtain the intermediate.

[0063] (5) Calcination in reducing atmosphere: The intermediate is placed in a hydrogen / argon mixed atmosphere with a hydrogen gas integral of 5%, and the temperature is increased to 500 °C at 5 °C / min. The temperature is held for 2 h and then naturally cooled to obtain a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst.

[0064] Example 3

[0065] A method for preparing a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, comprising the following steps:

[0066] (1) Alkali soaking pretreatment and single-step delignification of wood chips: Fir wood chips were placed in a 1 mol / L sodium hydroxide solution and soaked at a constant temperature of 60 °C for 5 h to perform swelling and degreasing treatment; after the alkali soaking, the chips were washed with deionized water until neutral and dried. The alkali-soaked wood chips were then transferred to a mixed solution of water, glacial acetic acid and sodium chlorite. The mass ratio of wood chips to the initially added water, glacial acetic acid and sodium chlorite was 2:200:1:3. The single-step delignification reaction was carried out at 75 °C under stirring for 3 h; after the reaction, the wood chips were taken out, washed and dried to obtain pretreated wood chips.

[0067] (2) Single metal salt impregnation at atmospheric pressure: Nickel acetylacetone was dissolved in methanol to prepare a metal salt A solution with a concentration of 2 mmol / mL; the pretreated wood chips obtained in step (1) were immersed in the metal salt A solution and impregnated at atmospheric pressure for 10 h; after removal, they were washed and dried to obtain wood chips loaded with single metal nickel.

[0068] (3) High temperature carbonization: The wood chips obtained in step (2) are placed in a tube furnace and heated to 800 ℃ at 5 ℃ / min under a nitrogen atmosphere. The temperature is held for 2 h and then naturally cooled to obtain carbon-based precursor sample B.

[0069] (4) Bimetallic solvothermal reaction: Cobalt nitrate and ammonium molybdate were dissolved in methanol to prepare mixed metal salt solutions with a concentration of 0.5 mmol / mL; sample B was added to the solution, stirred evenly, and then transferred to a reaction vessel for solvothermal reaction at 180 °C for 8 h; after cooling to room temperature, the solution was washed and dried to obtain the intermediate.

[0070] (5) Calcination in reducing atmosphere: The intermediate is placed in a hydrogen / argon mixed atmosphere with a hydrogen gas integral of 5%, and the temperature is increased to 500 °C at 5 °C / min. The temperature is held for 2 h and then naturally cooled to obtain a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst.

[0071] Example 4

[0072] A method for preparing a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, comprising the following steps:

[0073] (1) Alkali soaking pretreatment and single-step delignification of wood chips: Elm wood chips were placed in a 1 mol / L sodium hydroxide solution and soaked at a constant temperature of 75 °C for 3 h to perform swelling and degreasing treatment; after the alkali soaking, the chips were washed with deionized water until neutral and dried. The alkali-soaked wood chips were then transferred to a mixed solution of water, glacial acetic acid and sodium chlorite. The mass ratio of wood chips to the initially added water, glacial acetic acid and sodium chlorite was 2:200:1:3. The single-step delignification reaction was carried out at 85 °C under stirring for 2 h; after the reaction, the wood chips were taken out, washed and dried to obtain pretreated wood chips.

[0074] (2) Single metal salt impregnation at atmospheric pressure: Cobalt acetate was dissolved in ethanol to prepare a metal salt A solution with a concentration of 2.5 mmol / mL; the pretreated wood chips obtained in step (1) were immersed in the metal salt A solution and impregnated at atmospheric pressure for 4 h; after removal, they were washed and dried to obtain wood chips loaded with single metal cobalt.

[0075] (3) High temperature carbonization: The wood chips obtained in step (2) are placed in a tube furnace and heated to 600 ℃ at 5 ℃ / min under a nitrogen atmosphere. The temperature is held for 4 h and then naturally cooled to obtain carbon-based precursor sample B.

[0076] (4) Bimetallic solvothermal reaction: Nickel nitrate and ammonium molybdate were dissolved in ethanol to prepare mixed metal salt solutions with a concentration of 2.5 mmol / mL; Sample B was added to the solution, stirred evenly, and then transferred to a reaction vessel for solvothermal reaction at 180 °C for 8 h; After cooling to room temperature, the solution was washed and dried to obtain the intermediate.

[0077] (5) Calcination in reducing atmosphere: The intermediate is placed in a hydrogen / argon mixed atmosphere with a hydrogen gas integral of 5%, and the temperature is increased to 500 °C at 5 °C / min. The temperature is held for 2 h and then naturally cooled to obtain a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst.

[0078] Example 5

[0079] A method for preparing a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, comprising the following steps:

[0080] (1) Alkali soaking pretreatment and single-step delignification of wood chips: Birch wood chips were placed in a 1 mol / L sodium hydroxide solution and soaked at a constant temperature of 75 °C for 3 h to perform swelling and degreasing treatment; after the alkali soaking, the chips were washed with deionized water until neutral and dried. The alkali-soaked wood chips were then transferred to a mixed solution of water, glacial acetic acid and sodium chlorite. The mass ratio of wood chips to the initially added water, glacial acetic acid and sodium chlorite was 2:200:1:3. The single-step delignification reaction was carried out at 75 °C under stirring for 3 h; after the reaction, the wood chips were taken out, washed and dried to obtain pretreated wood chips.

[0081] (2) Single metal salt impregnation at atmospheric pressure: Iron chloride is dissolved in isopropanol to prepare a metal salt A solution with a concentration of 4 mmol / mL; the pretreated wood chips obtained in step (1) are immersed in the metal salt A solution and impregnated at atmospheric pressure for 10 h; after being taken out, they are washed and dried to obtain wood chips loaded with single metal iron.

[0082] (3) High temperature carbonization: The wood chips obtained in step (2) are placed in a tube furnace and heated to 800 ℃ at 5 ℃ / min under a nitrogen atmosphere. The temperature is held for 2 h and then naturally cooled to obtain carbon-based precursor sample B.

[0083] (4) Bimetallic solvothermal reaction: Copper chloride and ammonium phosphomolybdate were dissolved in isopropanol to prepare mixed metal salt solutions with a concentration of 4 mmol / mL; sample B was added to the solution, stirred evenly, and then transferred to a reaction vessel for solvothermal reaction at 80 °C for 10 h; after cooling to room temperature, the solution was washed and dried to obtain the intermediate.

[0084] (5) Calcination in reducing atmosphere: The intermediate is placed in a hydrogen / argon mixed atmosphere with a hydrogen gas integral of 5%, and the temperature is increased to 500 °C at 5 °C / min. The temperature is held for 2 h and then naturally cooled to obtain a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst.

[0085] Example 6

[0086] A method for preparing a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, comprising the following steps:

[0087] (1) Alkali soaking pretreatment and single-step delignification of wood chips: Eucalyptus wood chips were placed in a 2 mol / L sodium hydroxide solution and soaked at a constant temperature of 75 ℃ for 3 h to perform swelling and degreasing treatment; after the alkali soaking, the chips were washed with deionized water until neutral and dried. The alkali-soaked wood chips were then transferred to a mixed solution of water, glacial acetic acid and sodium chlorite. The mass ratio of wood chips to the initially added water, glacial acetic acid and sodium chlorite was 2:200:1:3. The single-step delignification reaction was carried out at 70 ℃ under stirring for 4 h; after the reaction, the wood chips were taken out, washed and dried to obtain pretreated wood chips.

[0088] (2) Single metal salt impregnation at atmospheric pressure: Copper acetate was dissolved in ethanol to prepare a metal salt A solution with a concentration of 5 mmol / mL; the pretreated wood chips obtained in step (1) were immersed in the metal salt A solution and impregnated at atmospheric pressure for 4 h; after removal, they were washed and dried to obtain single metal copper loaded wood chips.

[0089] (3) High temperature carbonization: The wood chips obtained in step (2) are placed in a tube furnace and heated to 1000 ℃ at 5 ℃ / min under a nitrogen atmosphere. The temperature is held for 1 h and then naturally cooled to obtain carbon-based precursor sample B.

[0090] (4) Bimetallic solvothermal reaction: Manganese acetate and ferric acetate were dissolved in ethanol to prepare mixed metal salt solutions with a concentration of 5 mmol / mL; sample B was added to the solution, stirred evenly, and then transferred to a reaction vessel for solvothermal reaction at 200 °C for 6 h; after cooling to room temperature, the solution was washed and dried to obtain the intermediate.

[0091] (5) Calcination in reducing atmosphere: The intermediate is placed in a hydrogen / argon mixed atmosphere with a hydrogen gas fraction of 20%, heated to 800 ℃ at 20 ℃ / min, held for 6 h, and then naturally cooled to obtain a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst.

[0092] Comparative Example 1

[0093] To further verify the performance advantages of the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst described in this invention, the following comparative examples were set up to prepare a single-component metal oxide catalyst, with the following steps:

[0094] (1) Alkali soaking pretreatment and single-step delignification of wood chips: Pine wood chips were placed in a 1 mol / L sodium hydroxide solution and soaked at a constant temperature of 75 °C for 3 h to perform swelling and degreasing treatment; after the alkali soaking, the chips were washed with deionized water until neutral and dried. The alkali-soaked wood chips were then transferred to a mixed solution of water, glacial acetic acid and sodium chlorite. The mass ratio of wood chips to the initially added water, glacial acetic acid and sodium chlorite was 2:200:1:3. The single-step delignification reaction was carried out at 75 °C under stirring for 3 h; after the reaction, the wood chips were taken out, washed and dried to obtain pretreated wood chips.

[0095] (2) Bimetallic salt co-impregnation: Nickel nitrate and ammonium molybdate are dissolved in deionized water at a molar ratio of 1:1 to prepare a mixed metal salt solution with a total concentration of 2 mmol / mL; the pretreated wood chips obtained in step (1) are immersed in the mixed metal salt solution and left to stand under normal pressure for 6 h; after removal, they are washed and dried to obtain bimetallic impregnated wood chips.

[0096] (3) One-step solvothermal + oxidation: The wood chips obtained in step (2) were directly transferred into the reactor, and an appropriate amount of deionized water was added. The reaction was carried out at 120 °C for 6 h. After cooling to room temperature, the wood chips were washed and dried. Then, in an air atmosphere, the temperature was increased to 400 °C at 5 °C / min and kept for 2 h to obtain Comparative Example 1 (NiMoO4 / CWC).

[0097] Comparative Example 2

[0098] To further verify the performance advantages of the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst described in this invention, the following comparative examples were set up to prepare a single-component metal oxide catalyst, with the following steps:

[0099] (1) Alkali soaking pretreatment and single-step delignification of wood chips: Poplar wood chips were placed in a 1 mol / L sodium hydroxide solution and soaked at a constant temperature of 75 °C for 3 h to perform swelling and degreasing treatment; after the alkali soaking, the chips were washed with deionized water until neutral and dried. The alkali-soaked wood chips were then transferred to a mixed solution of water, glacial acetic acid and sodium chlorite. The mass ratio of wood chips to the initially added water, glacial acetic acid and sodium chlorite was 2:200:1:3. The single-step delignification reaction was carried out at 75 °C under stirring for 3 h; after the reaction, the wood chips were taken out, washed and dried to obtain pretreated wood chips.

[0100] (2) Bimetallic salt co-impregnation (control group): Cobalt nitrate and ammonium molybdate were dissolved in deionized water at a molar ratio of 1:1 to prepare a mixed metal salt solution with a total concentration of 2 mmol / mL; the pretreated wood chips obtained in step (1) were immersed in the mixed metal salt solution and allowed to stand under normal pressure for 6 h; after removal, they were washed and dried to obtain bimetallic impregnated wood chips.

[0101] (3) One-step solvothermal + oxidation: The wood chips obtained in step (2) were directly transferred into the reactor, and an appropriate amount of deionized water was added. The reaction was carried out at 120 °C for 6 h. After cooling to room temperature, the wood chips were washed and dried. Then, in an air atmosphere, the temperature was increased to 400 °C at 5 °C / min and kept for 2 h to obtain Comparative Example 2 (CoMoO4 / CWC).

[0102] Comparative Example 3

[0103] To further verify the performance advantages of the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst described in this invention, the following comparative examples were set up to prepare alloy single-component catalysts, and the steps are as follows:

[0104] (1) Alkali soaking pretreatment and single-step delignification of wood chips: Fir wood chips were placed in a 1 mol / L sodium hydroxide solution and soaked at a constant temperature of 75 °C for 3 h to perform swelling and degreasing treatment; after the alkali soaking, the chips were washed with deionized water until neutral and dried. The alkali-soaked wood chips were then transferred to a mixed solution of water, glacial acetic acid and sodium chlorite. The mass ratio of wood chips to the initially added water, glacial acetic acid and sodium chlorite was 2:200:1:3. The single-step delignification reaction was carried out at 75 °C under stirring for 3 h; after the reaction, the wood chips were taken out, washed and dried to obtain pretreated wood chips.

[0105] (2) Bimetallic salt co-impregnation: Nickel nitrate and cobalt nitrate were dissolved in deionized water at a molar ratio of 1:1 to prepare a mixed metal salt solution with a total concentration of 2 mmol / mL; the pretreated wood chips obtained in step (1) were immersed in the mixed metal salt solution and allowed to stand under normal pressure for 6 h; after removal, they were washed and dried to obtain bimetallic impregnated wood chips.

[0106] (3) One-step carbonization + reduction: The wood chips obtained in step (2) were placed in a tube furnace and heated to 800 ℃ at 5 ℃ / min under a nitrogen atmosphere. The temperature was held for 2 h and then naturally cooled to obtain a carbon-based precursor. The precursor was then placed in a hydrogen / argon mixed atmosphere (hydrogen gas fraction 10%) and heated to 500 ℃ at 5 ℃ / min. The temperature was held for 3 h and then naturally cooled to obtain Comparative Example 3 (NiCo / CWC).

[0107] The catalysts prepared in Examples 1–6 and Comparative Examples 1–3 were subjected to linear sweep voltammetry (LSV) tests in a 1.0 mol / L KOH electrolyte containing 0.5 mol / L urea. The test area was 0.2 cm² in all cases. 2 The catalyst was tested to reach -10 mA / cm during the HER process. 2 300 mA / cm during UOR process 2 The overpotential at that time was calculated, and the corresponding Tafel slope was obtained based on LSV curve fitting. The specific results are shown in Table 1 and Table 2 below.

[0108] The polarization curves of the hydrogen evolution reaction of the catalysts prepared in Examples 1 and 1-3 (comparative Examples 1-3) in a 1.0 mol / L potassium hydroxide solution containing 0.5 mol / L urea are shown in the figure. Figure 6 .

[0109] Table 1 Electrochemical hydrogen evolution performance in potassium hydroxide / urea solution

[0110]

[0111] Table 2 Electrochemical urea oxidation performance in potassium hydroxide / urea solution

[0112]

[0113] As can be seen from Tables 1 and 2, the wood-derived carbon-supported metal oxide-alloy heterojunction catalyst described in this invention exhibits excellent catalytic performance for both the hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) in an alkaline urea system, achieving a catalytic efficiency of -10 mA / cm² during the HER process. 2 Required overpotential less than 68 mV; 300 mA / cm during UOR process. 2The required potential is below 1.38 V. In contrast, the comparative example achieved -10 mA / cm during the HER process. 2 The required overpotential is above 84 mV; during the UOR process, it reaches 300 mA / cm. 2 The required potential is higher than 1.40 V. Therefore, it can be seen that the catalyst prepared in this invention exhibits significantly better low overpotential, high current density, and rapid kinetic characteristics than the comparative sample.

[0114] according to Figure 1 The SEM images show that the catalyst prepared in Example 1 (NiCo@Ni-CoMoO4 / CWC) has an array structure with abundant nanosheets supported on a carbonized wood substrate. This indicates that the wood retains a porous framework structure after pretreatment and carbonization, providing abundant accessible sites for the in-situ construction of subsequent metal components, which is beneficial for charge transport and bubble desorption during the catalytic reaction.

[0115] Figure 2 TEM images and Figure 3 The EDS results confirmed that the nanosheets on the carbonized wood substrate in the prepared catalyst were composed of metal oxides (NiMoO4 and CoMoO4) and alloys (NiCo), and the transition metals (Ni, Co, Mo) and oxygen elements were uniformly dispersed in the carbon substrate, indicating that the metal components were highly distributed in the entire catalyst system.

[0116] Depend on Figure 4 The XRD pattern shows that the catalyst prepared in Example 1 exhibits characteristic diffraction peaks of both metal alloys and metal oxides, but no obvious carbon diffraction peaks of wood-derived carbon. This may be due to the rich and dense metal oxide-alloy heterostructure nanosheet array structure covering the derived carbon on the substrate surface.

[0117] Further Raman scattering spectroscopy was performed on Example 1. Figure 5 The Raman spectroscopy results showed that the catalyst prepared in Example 1 exhibited a high performance at 1360 cm⁻¹. -1 and 1590 cm -1 There are obvious defect peaks (D peak) and graphite peaks (G peak) attributable to wood-derived carbon in the vicinity, and the intensity ratio (I) D / I G =0.82) indicates that the carbon substrate in the prepared catalyst has a moderate defect density and a certain degree of graphitization, possessing both a large number of active sites such as edge defects and vacancy defects, and retaining good conjugated sp. 2 Carbon structures are beneficial for improving the electron transport capability and structural stability of materials.

[0118] at the same time, Figure 5The presence of typical D and G peaks in the Raman spectrum directly confirms the actual existence of the wood-derived carbon substrate in the catalyst, compensating for the lack of obvious carbon characteristic peaks in XRD. Furthermore, the Raman spectrum also reveals the presence of Ni-O, Co-O, and Mo-O bonds originating from metal oxides (NiMoO4 and CoMoO4), further demonstrating that the catalyst of this invention successfully constructs a multiphase heterostructure with coexisting metal oxides and alloys on the wood-derived carbon substrate.

[0119] Tables 1 and 2 show that the catalyst described in this invention exhibits significantly superior catalytic activity in urea-containing alkaline electrolytes:

[0120] During the HER process, it reached -10 mA / cm 2 The required overpotential is less than 68 mV;

[0121] During the UOR process, it reached 300 mA / cm 2 The required potential is below 1.38 V.

[0122] The above performance is significantly better than that of the single-component NiMoO4 / CWC, CoMoO4 / CWC, and NiCo / CWC in Comparative Examples 1–3, which fully demonstrates that the in-situ construction of multiphase heterojunctions can significantly improve catalytic performance.

[0123] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection of the present invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of the present invention, or equivalent structural or procedural transformations made using the content of the present invention's specification and drawings, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of patent protection of the present invention.

Claims

1. A method for preparing a wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, characterized in that: It includes the following steps: Step 1: Alkali Pretreatment and Delignification of Wood Chips: First, immerse the wood chips in an alkaline solution. After alkali immersion, wash the wood chips with deionized water until neutral and dry them. Then, perform delignification treatment on the alkali-immersed wood chips. After the reaction is complete, remove the wood chips, wash and dry them to obtain pretreated wood chips. Step 2: Single metal salt impregnation at atmospheric pressure: Dissolve metal salt A in solvent A to prepare metal salt A solution. Immerse the pretreated wood chips obtained in Step 1 directly into the metal salt A solution and let them stand under atmospheric pressure for 4–10 hours. After removal, wash and dry to obtain single metal-loaded wood chips. The metal salt A is one of nickel salt, cobalt salt, molybdenum salt, copper salt, iron salt, and manganese salt. Step 3: High-temperature carbonization: The single-metal supported wood chips obtained in Step 2 are placed in a tube furnace and calcined at 600–1000 °C for 1–4 hours under a nitrogen atmosphere to obtain carbon-based precursor sample B. Step 4: Dissolve two different metal salts D and E in solvent A to prepare a mixed metal salt solution; add the sample B obtained in step 3 to the mixed metal salt solution, stir evenly, and then transfer to a reaction vessel for a solvothermal reaction at 80–200 °C for 6–10 hours; after the reaction is completed, cool, wash, and dry to obtain an intermediate loaded with bimetallic components; Step 5: Annealing: The intermediate obtained in Step 4 is placed in a mixed atmosphere of hydrogen and argon and calcined at 400–800 °C for 2–6 hours to generate a metal oxide-alloy multiphase heterojunction in situ, thus obtaining the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst.

2. The method for preparing the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst according to claim 1, characterized in that: The wood chips in step 1 are one of the following: pine, fir, poplar, elm, birch, camphor, or eucalyptus.

3. The method for preparing the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst according to claim 1, characterized in that: Step 1 specifically involves: placing the wood chips in a 0.5–2 mol / L sodium hydroxide solution and immersing them at a constant temperature of 60–90 °C for 2–5 h to induce swelling and degreasing; after immersion, washing the wood chips with deionized water until neutral and drying them; then placing the immersed wood chips in a mixture of water, glacial acetic acid, and sodium chlorite, with a mass ratio of wood chips to initially added water, glacial acetic acid, and sodium chlorite of 2:200:1:3, and reacting at 70–85 °C with stirring for 2–5 h to perform delignification; after the reaction, removing the wood chips, washing, and drying them to obtain pretreated wood chips.

4. The method for preparing the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst according to claim 1, characterized in that: In step 2, solvent A is one of water, methanol, ethanol, isopropanol, n-butanol, cyclohexane, diethyl ether, and ethyl acetate.

5. The method for preparing the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst according to claim 1, characterized in that: In step 2, the concentration of the metal salt A solution is 0.5–5 mmol / mL.

6. The method for preparing the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst according to claim 1, characterized in that: In step 4, the concentrations of metal salt D and metal salt E are both 0.5–5 mmol / mL.

7. The method for preparing the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst according to claim 1 or 6, characterized in that: The metal salts D and E are selected from any one of the metal salts of nickel, cobalt, molybdenum, copper, iron, and manganese, and are all different from the metal salt A.

8. The method for preparing the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst according to claim 1, characterized in that: In step 5, the calcination heating rate is 2–20 °C / min, and the volume fraction of hydrogen in the mixed gas is 5%–20%.

9. A wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

10. The application of the wood-derived carbon-supported metal oxide-alloy multiphase heterojunction catalyst according to claim 9, characterized in that: The application of the wood-derived carbon-supported metal oxide-alloy heterojunction catalyst as a catalyst in electrocatalytic hydrogen evolution reaction and urea oxidation reaction.

Images