A high-loaded lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni ternary heterojunction composite material and its preparation and application

Abstract

The present invention discloses a high-load lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni ternary heterojunction composite material and its preparation and application. The method comprises: mixing lignin, zinc salt, and nickel salt in the form of a solution; then adding a precipitant solution and water; heating the reaction, washing, drying, and carbonizing to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials. 0.7 / ZnO / Ni composite materials have disadvantages as catalysts, such as low optical performance and high and unstable recombination rate. Using the material in the field of photothermal catalytic reforming of biomass to produce hydrogen can significantly improve the hydrogen production efficiency. This material has potential application value in the field of photothermal catalytic reforming of biomass to produce hydrogen.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic / inorganic hybrid composite materials, and specifically relates to a high-load lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni ternary heterojunction composite materials and their preparation and applications. Background Art

[0002] Faced with increasingly depleted fossil fuels and escalating environmental problems, the search for sustainable and renewable energy has become a serious global challenge. Among various potential alternative energy sources, hydrogen stands out as a clean and efficient energy carrier with the potential to significantly reduce greenhouse gas emissions. However, the production of hydrogen has traditionally relied on energy-intensive and carbon-emitting processes. Photothermal catalysis has emerged as an environmentally friendly, green and efficient method that uses solar energy to drive chemical reactions for hydrogen production. This technology exploits the ability of certain materials to absorb light and convert it into heat energy, thereby promoting endothermic reactions. In this context, lignin-based carbon materials and cellulose, two of the most abundant biopolymers on Earth, have attracted much attention due to their potential role in improving the efficiency and sustainability of photothermal catalytic processes.

[0003] Nickel and zinc play key roles in photothermal catalytic hydrogen production. Nickel enhances catalytic efficiency through its excellent hydrogen adsorption properties, while zinc improves stability and light absorption capacity, thereby increasing overall productivity. Their synergistic effect optimizes reaction conditions, making it an ideal choice for sustainable energy solutions.

[0004] Ni3ZnC 0.7 / ZnO / Ni ternary heterojunction composite materials have great potential in photothermal catalytic hydrogen production due to their unique electronic properties and stronger light absorption ability. However, challenges still exist, such as the high cost and complexity of the preparation process. Under the catalytic reaction conditions, Ni3ZnC 0.7 Ternary heterojunction composites suffer from poor stability and are prone to deactivation, and it is difficult to optimize the balance between the components to achieve maximum efficiency. Addressing these issues is crucial to promoting their practical application in the field of sustainable hydrogen energy.

[0005] Lignin, a complex aromatic polymer, is a major component of plant secondary cell walls, playing a key role in providing mechanical strength and resisting microbial attack. Despite its abundance, lignin is underutilized and primarily considered a waste product in the papermaking industry. However, recent advances in materials science and biorefining processes have revealed the potential of lignin as a valuable resource. Lignin's structure is rich in aromatic rings and hydroxyl groups, making it ideal for conversion into carbon-based materials with excellent photothermal properties. These lignin-derived carbon materials possess exceptional light absorption and thermal conductivity, making them ideal candidates for photothermal catalysis. Lignin-derived carbons, due to their large surface area, provide ample sites for catalyst loading, supporting the catalyst and creating a support effect. Furthermore, the high degree of graphitization of lignin carbons improves electron transfer, stability, selectivity, and active site efficiency of the composites, enhancing their overall catalytic performance. Converting lignin into such functional materials not only recapitulates a previously wasted resource but also paves the way for sustainable hydrogen production by leveraging the inherent properties of biomass. Summary of the Invention

[0006] In order to overcome the above-mentioned Ni3ZnC 0.7 / ZnO / Ni is complex in preparation process, high in cost and difficult to maintain Ni3ZnC under catalytic reaction conditions. 0.7 Structural stability (easy to deactivate) and optimization of Ni3ZnC 0.7 / ZnO / Ni components to achieve the highest efficiency and other issues, the primary purpose of the present invention is to provide a high-load lignin-derived carbon / Ni3ZnC 0.7 A method for preparing a ZnO / Ni ternary heterojunction composite material.

[0007] The present invention uses lignin as a surfactant and carbon source, and prepares lignin-derived carbon / Ni3ZnC with different proportions, high loading and high catalytic performance by calcining at high temperature in a two-step method. 0.7 / ZnO / Ni ternary heterojunction composite materials. Lignin not only provides a carbon source but also acts as a surfactant in the solution; it also disperses the metal particles during synthesis. The carbon loading broadens the composite's absorption range, increases its specific surface area, and acts as a carrier and support, enhancing the catalyst's structural stability and catalytic capacity. This process offers the advantages of simplicity, readily available raw materials, and low cost.

[0008] Another object of the present invention is to provide a lignin-derived carbon / Ni3ZnC prepared by the above preparation method. 0.7 / ZnO / Ni ternary heterojunction composite material.

[0009] Another object of the present invention is to provide the above-mentioned lignin-derived carbon / Ni3ZnC 0.7 Application of / ZnO / Ni ternary heterojunction composite materials.

[0010] The purpose of the present invention is achieved through the following technical solutions:

[0011] Lignin-derived carbon / Ni3ZnC 0.7 A method for preparing a ZnO / Ni ternary heterojunction composite material comprises the following steps:

[0012] (1) The lignin alcohol solution and the mixed salt solution of zinc salt and nickel salt are mixed evenly, the precipitant solution is added dropwise, and then water is added, heated for reaction, washed, and dried to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni ternary heterojunction composite material precursor;

[0013] (2) Lignin-derived carbon / Ni3ZnC 0.7 The precursor of the ternary heterojunction composite material is calcined to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni ternary heterojunction composite material.

[0014] Preferably, in step (1), the ratio of lignin, zinc salt and nickel salt is 1.5-2.5 g:5-10 mmol:5-10 mmol; more preferably 2 g:5-10 mmol:5-10 mmol; most preferably 2 g:10 mmol:10 mmol.

[0015] Preferably, in step (1), the molar ratio of the precipitant, the zinc salt and the nickel salt is 5-8:0.5-2:0.5-2; more preferably 7-8:0.5-1:0.5-1; most preferably 8:1:1.

[0016] Preferably, the lignin in step (1) is at least one of alkali lignin, sulfate lignin, lignin sulfonate and enzymatic lignin; more preferably, it is alkali lignin.

[0017] Preferably, the concentration of the lignin alcohol solution in step (1) is 12.5 to 62.5 mg / mL; more preferably 37.5 to 62.5 mg / mL; most preferably 37.5 to 50 mg / mL.

[0018] Preferably, the alcohol solvent in the lignin alcohol solution in step (1) is anhydrous ethanol.

[0019] Preferably, the concentration of the mixed salt solution of zinc salt and nickel salt in step (1) is 0.5-1 mol / L; more preferably 0.75-1 mol / L; most preferably 1 mol / L.

[0020] Preferably, the zinc salt in step (1) is at least one of zinc nitrate, zinc acetate, zinc carbonate, zinc chloride and zinc oxalate; more preferably, it is zinc nitrate.

[0021] Preferably, the nickel salt in step (1) is at least one of nickel nitrate, nickel acetate, nickel carbonate and nickel chloride; more preferably nickel nitrate.

[0022] Preferably, the precipitant solution in step (1) is at least one of aqueous ammonia, potassium hydroxide solution and sodium hydroxide solution; more preferably sodium hydroxide solution; the concentration of the precipitant solution is 5 to 9 mol / L; further preferably 5 to 8 mol / L; most preferably 7 to 8 mol / L.

[0023] Preferably, the volume ratio of the water added in step (1) to the precipitant solution is (0-80):10, and the volume of water is not 0; more preferably, it is (15-30):10; and most preferably, it is 30:10.

[0024] Preferably, the temperature of the heating reaction in step (1) is 60-100° C., and the time is 40-120 min; more preferably, the temperature of the heating reaction is 80-90° C., and the time is 60-120 min.

[0025] Preferably, the washing in step (1) refers to washing the heated reaction product mixture with deionized water and anhydrous ethanol after centrifugation; more preferably, washing with deionized water and anhydrous ethanol 1 to 5 times each.

[0026] Preferably, the drying in step (1) is conventional drying.

[0027] Preferably, the calcination temperature in step (2) is 450-550°C, more preferably 500-550°C, most preferably 550°C; and the calcination time is 1-3 hours, most preferably 1 hour.

[0028] Preferably, the heating rate of the calcination in step (2) is 1 to 10°C / min; more preferably 3 to 6°C / min; most preferably 5°C / min.

[0029] Preferably, the calcination atmosphere in step (2) is at least one of nitrogen, ammonia and air; preferably nitrogen.

[0030] A lignin-derived carbon / Ni3ZnC prepared by the above preparation method 0.7 / ZnO / Ni ternary heterojunction composite material.

[0031] The above-mentioned lignin-derived carbon / Ni3ZnC 0.7 Application of / ZnO / Ni ternary heterojunction composite materials in the field of photothermal catalysis.

[0032] Preferably, the application is photothermal catalytic reforming of cellulose to produce hydrogen.

[0033] More preferably, the method for photothermal catalytic reforming of cellulose to produce hydrogen is: lignin-derived carbon / Ni3ZnC 0.7 The mass ratio of the ZnO / Ni ternary heterojunction composite material to the substrate is 1:5-15; the temperature of the catalytic reaction is 453-493K.

[0034] More preferably, the substrate comprises ethanol and cellulose, wherein the mass ratio of ethanol to cellulose is 5 to 15:1.

[0035] The present invention provides a lignin-derived carbon / Ni3ZnC prepared by the above method 0.7 / ZnO / Ni ternary heterojunction composite material has the advantages of good stability, rich pore volume and pore size, large specific surface area, strong catalytic effect, etc. It is applied to the field of photothermal catalysis, especially in the research of photothermal catalytic reforming of cellulose to produce hydrogen, which can significantly improve its photothermal catalytic performance. 0.7 / ZnO / Ni combined, can make up for Ni3ZnC 0.7 The shortcomings of the ZnO / Ni / Z ...

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] The present invention uses lignin as a carbon source and a surfactant to change the interfacial energy of water and anhydrous ethanol, thereby improving the mutual self-assembly ability of lignin, Zn and Ni in the liquid; at the same time, the use of an alkaline precipitant can improve the dispersion ability of lignin in the mixed liquid; during the carbonization process, lignin-derived carbon / Ni3ZnC is formed in situ. 0.7 / ZnO / Ni composite material. In the polycrystalline structure, Ni is formed as the center and Ni3ZnC 0.7 The ZnO and Ni3ZnC form twin heterojunctions, which improve the electron transport ability of the composite material during the catalytic process. The interaction between the components enhances the Ni3ZnC 0.7 The stability and Ni3ZnC 0.7The hydrogen evolution performance of the lignin / ZnO / Ni composite optimizes the photothermal catalytic process. Thanks to the carrier and support effects of the lignin carbon, the ternary structure remains stable under varying photothermal conditions, maintaining activity for extended periods. Furthermore, the composite structure allows for broader light absorption, maximizing photothermal conversion efficiency. Application of this material in photothermal catalysis, particularly photothermal hydrogen production, could significantly improve hydrogen production efficiency, facilitating its promotion in industrial applications for sustainable hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 7 0.7 X-ray diffraction patterns of the / ZnO / Ni composite material and the composite material prepared in Comparative Example 1.

[0039] Figure 2 Lignin-derived carbon / Ni3ZnC prepared in Example 1 0.7 Scanning electron microscope image of / ZnO / Ni composite material.

[0040] Figure 3 Lignin-derived carbon / Ni3ZnC prepared in Example 2 0.7 Scanning electron microscope image of / ZnO / Ni composite material.

[0041] Figure 4 Lignin-derived carbon / Ni3ZnC prepared in Example 3 0.7 Scanning electron microscope image of / ZnO / Ni composite material.

[0042] Figure 5 Lignin-derived carbon / Ni3ZnC prepared in Example 4 0.7 Scanning electron microscope image of / ZnO / Ni composite material.

[0043] Figure 6 Lignin-derived carbon / Ni3ZnC prepared in Example 5 0.7 Scanning electron microscope image of / ZnO / Ni composite material.

[0044] Figure 7 This is a scanning electron microscope image of the composite material prepared in Comparative Example 1.

[0045] Figure 8 Lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 3 0.7 Nitrogen adsorption-desorption isotherms and pore size distribution of / ZnO / Ni composite materials.

[0046] Figure 9 Lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 3 0.7 Raman spectrum of / ZnO / Ni composite material.

[0047] Figure 10 Lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 3 0.7 Infrared thermal imaging of ZnO / Ni composite material under illumination (500W xenon lamp).

[0048] Figure 11 Lignin-derived carbon / Ni3ZnC prepared in Example 1 0.7 Transmission electron microscopy (TEM) images, particle size distribution, high-magnification TEM images, and lattice measurement images of the / ZnO / Ni composite material.

[0049] Figure 12 Lignin-derived carbon / Ni3ZnC prepared in Example 1 0.7 Mapping diagram of / ZnO / Ni composite material.

[0050] Figure 13 Lignin-derived carbon / Ni3ZnC prepared in Example 1 0.7 / ZnO / Ni composite material in ethanol, α-cellulose and ethanol and α-cellulose mixture to produce hydrogen.

[0051] Figure 14 Lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 7 0.7 / ZnO / Ni composite material and the composite material prepared in comparative example 1 in hydrogen production effect in ethanol and α-cellulose mixed liquid. DETAILED DESCRIPTION

[0052] The present invention will be described in further detail below with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

[0053] In the examples of the present invention, if the specific conditions are not specified, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. All raw materials and reagents used without specifying the manufacturer are conventional products that can be purchased from the market.

[0054] Example 1

[0055] 2.0 g of alkali lignin was added to 40 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Then, 10 ml of 8 mol / L sodium hydroxide solution and 10 ml of 1 mol / L mixed salt solution of zinc nitrate hexahydrate and nickel nitrate hexahydrate were prepared, wherein the molar ratio of zinc nitrate hexahydrate to nickel nitrate hexahydrate was 1:1. The mixed salt solution was added to the mixture of alkali lignin and ethanol, stirred for 10 min, and then the prepared sodium hydroxide solution was added dropwise and then 30 ml of water was added. The mixture was then placed in a water bath and heated at 80 ° C for 60 min. The reaction mixture was then centrifuged, washed with deionized water and anhydrous ethanol 3 times each, and dried overnight to obtain lignin-derived carbon / Ni3ZnC0.7 / ZnO / Ni material precursor, and then put the precursor into a tube furnace, and heat it to 550℃ at a heating rate of 5℃ / min under nitrogen atmosphere and calcine it for 1h, and then cool it to room temperature to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials.

[0056] Example 2

[0057] 2.0 g of alkali lignin was added to 40 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Then, 10 ml of 5 mol / L sodium hydroxide solution, 10 ml of 0.5 mol / L zinc nitrate hexahydrate solution and 10 ml of 1 mol / L nickel nitrate hexahydrate solution were prepared. The zinc nitrate hexahydrate solution and the nickel nitrate hexahydrate solution were mixed to obtain a mixed salt solution. The mixed salt solution was then added to the mixture of alkali lignin and ethanol. After stirring for 10 min, the prepared sodium hydroxide solution was added dropwise and then 30 ml of water was added. The mixture was then placed in a water bath and heated at 80 ° C for 60 min. The reaction mixture was then centrifuged, washed with deionized water and anhydrous ethanol 3 times each, and dried overnight to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni material precursor, and then put the precursor into a tube furnace, and heat it to 550℃ at a heating rate of 5℃ / min under nitrogen atmosphere and calcine it for 1h, and then cool it to room temperature to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials.

[0058] Example 3

[0059] 2.0 g of alkali lignin was added to 40 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Then, 10 ml of 7 mol / L sodium hydroxide solution, 10 ml of 1 mol / L zinc nitrate hexahydrate solution and 10 ml of 0.5 mol / L nickel nitrate hexahydrate solution were prepared. The zinc nitrate hexahydrate solution and the nickel nitrate hexahydrate solution were mixed to obtain a mixed salt solution. The mixed salt solution was then added to the mixture of alkali lignin and ethanol. After stirring for 10 min, the prepared sodium hydroxide solution was added dropwise and then 30 ml of water was added. The mixture was then placed in a water bath and heated at 80 ° C for 60 min. The reaction mixture was then centrifuged, washed with deionized water and anhydrous ethanol 3 times each, and dried overnight to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni material precursor, and then put the precursor into a tube furnace, and heat it to 550℃ at a heating rate of 5℃ / min under nitrogen atmosphere and calcine it for 1h, and then cool it to room temperature to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials.

[0060] Example 4

[0061] 1.5 g of alkali lignin was added to 40 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Then, 10 ml of 8 mol / L sodium hydroxide solution and 10 ml of 1 mol / L mixed salt solution of zinc nitrate hexahydrate and nickel nitrate hexahydrate were prepared, wherein the molar ratio of zinc nitrate hexahydrate to nickel nitrate hexahydrate was 1:1. The mixed salt solution was added to the mixture of alkali lignin and ethanol, stirred for 10 min, and then the prepared sodium hydroxide solution was added dropwise and then 30 ml of water was added. The mixture was then placed in a water bath and heated at 80 ° C for 60 min. The reaction mixture was then centrifuged, washed with deionized water and anhydrous ethanol 3 times each, and dried overnight to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni material precursor, and then put the precursor into a tube furnace, and heat it to 550℃ at a heating rate of 5℃ / min under nitrogen atmosphere and calcine it for 1h, and then cool it to room temperature to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials.

[0062] Example 5

[0063] 2.5 g of alkali lignin was added to 40 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Then, 10 ml of 8 mol / L sodium hydroxide solution and 10 ml of 1 mol / L mixed salt solution of zinc nitrate hexahydrate and nickel nitrate hexahydrate were prepared, wherein the molar ratio of zinc nitrate hexahydrate to nickel nitrate hexahydrate was 1:1. The mixed salt solution was added to the mixture of alkali lignin and ethanol, stirred for 10 min, and then the prepared sodium hydroxide solution was added dropwise and then 30 ml of water was added. The mixture was then placed in a water bath and heated at 80 ° C for 60 min. The reaction mixture was then centrifuged, washed with deionized water and anhydrous ethanol 3 times each, and dried overnight to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni material precursor, and then put the precursor into a tube furnace, and heat it to 550℃ at a heating rate of 5℃ / min under nitrogen atmosphere and calcine it for 1h, and then cool it to room temperature to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials.

[0064] Example 6

[0065] 2.0 g of alkali lignin was added to 40 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Then, 10 ml of 8 mol / L sodium hydroxide solution and 10 ml of 1 mol / L mixed salt solution of zinc nitrate hexahydrate and nickel nitrate hexahydrate were prepared, wherein the molar ratio of zinc nitrate hexahydrate to nickel nitrate hexahydrate was 1:1. The mixed salt solution was added to the mixture of alkali lignin and ethanol, stirred for 10 min, and then the prepared sodium hydroxide solution was added dropwise and then 30 ml of water was added. The mixture was then placed in a water bath and heated at 80 ° C for 60 min. The reaction mixture was then centrifuged, washed with deionized water and anhydrous ethanol 3 times each, and dried overnight to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni material precursor, and then put the precursor into a tube furnace, and heat it to 450℃ at a heating rate of 5℃ / min under nitrogen atmosphere and calcine it for 3h, and cool it to room temperature to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials.

[0066] Example 7

[0067] 2.0 g of alkali lignin was added to 40 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Then, 10 ml of 8 mol / L sodium hydroxide solution and 10 ml of 1 mol / L mixed salt solution of zinc nitrate hexahydrate and nickel nitrate hexahydrate were prepared, wherein the molar ratio of zinc nitrate hexahydrate to nickel nitrate hexahydrate was 1:1. The mixed salt solution was added to the mixture of alkali lignin and ethanol, stirred for 10 min, and then the prepared sodium hydroxide solution was added dropwise and then 30 ml of water was added. The mixture was then placed in a water bath and heated at 90 ° C for 120 min. The reaction mixture was then centrifuged, washed with deionized water and anhydrous ethanol 3 times each, and dried overnight to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni material precursor, and then put the precursor into a tube furnace, and heat it to 550℃ at a heating rate of 5℃ / min under nitrogen atmosphere and calcine it for 1h, and then cool it to room temperature to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials.

[0068] Comparative Example 1

[0069] 2.0 g of phthalic acid was added to 40 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Then, 10 ml of 8 mol / L sodium hydroxide solution and 10 ml of 1 mol / L mixed salt solution of zinc nitrate hexahydrate and nickel nitrate hexahydrate were prepared, wherein the molar ratio of zinc nitrate hexahydrate to nickel nitrate hexahydrate was 1:1. The mixed salt solution was added to the mixture of alkali lignin and ethanol, stirred for 10 min, and then the prepared sodium hydroxide solution was added dropwise and then 30 ml of water was added. The mixture was then placed in a water bath and heated at 80 ° C for 60 min. The reaction mixture was then centrifuged, washed with deionized water and anhydrous ethanol 3 times each, and dried overnight to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni material precursor, and then put the precursor into a tube furnace, and heat it to 550℃ at a heating rate of 5℃ / min under nitrogen atmosphere and calcine it for 1h, and then cool it to room temperature to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials.

[0070] Example Effect Description

[0071] The prepared lignin-derived carbon / Ni3ZnC was measured using a Rigaku D / Max-2400 X-ray powder diffractometer according to the test method (10°~80°, 10° / min). 0.7 The crystal structure of the prepared lignin-derived carbon / Ni3ZnC / ZnO / Ni composite material was observed using a Hitachi SU8220 field emission scanning electron microscope. 0.7 The microstructure of the prepared lignin-derived carbon / Ni3ZnC was tested using a Micromeritics ASAP2460 physical adsorption analyzer. 0.7 The specific surface area and pore structure of the prepared lignin-derived carbon / Ni3ZnC / ZnO / Ni composite material were analyzed using LabRAMramis micro-Raman spectrometer. 0.7 Carbonization effect of / ZnO / Ni composite materials; FLIR T840 infrared thermal imager was used to test the carbonization effect of lignin-derived carbon / Ni3ZnC 0.7 The photothermal conversion capacity of the prepared lignin-derived carbon / Ni3ZnC / ZnO / Ni composite material was observed using a Thermo Fisher Talos F200s transmission electron microscope. 0.7 Lattice size and element distribution of / ZnO / Ni composites.

[0072] Table 1 Specific surface area and pore volume of examples

[0073]

[0074] Figure 1 Lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 70.7 X-ray diffraction patterns of the composite material prepared in Example 1 and the composite material prepared in Example 1. 0.7 The characteristic peak shapes of ZnO and Ni are shown in Table 1. Due to the different ratios of Ni and Zn in Examples 1 to 3, the crystal strength of the composite materials obtained is also different. When the Zn ratio is higher than that of Ni, the crystal strength of the generated ZnO is better (Example 2); when the Ni ratio is higher than that of Zn, the Ni3ZnC 0.7 When the amount of lignin added was 1.5 g (Example 4), the Ni3ZnC 0.7 The crystal form of the phase is the best, which may be because less Ni is reduced during calcination compared to when the addition amount is 2g, which can promote the conversion of part of NiZn alloy into Ni3ZnC 0.7 , thus making Ni3ZnC 0.7 The crystal form of the phase is good. The crystal strength of Example 5 is higher than that of Example 1, which may be because too much lignin provides too many loading sites, and a metal catalyst is generated in situ during the calcination process, thereby making the crystal strength of the material higher than that of Example 1. The changes in the calcination temperature, reaction time and reaction temperature in Examples 6 and 7 do not significantly change the composition phase of the composite material. A calcination temperature below 550°C will reduce the strength of the crystal, while correspondingly extending the reaction time and increasing the reaction temperature will increase the crystal strength of the composite material. Comparative Example 1 is a composite material prepared by using phthalic acid instead of lignin. It can be seen that the prepared material is composed of ZnO and Ni. This may be because phthalic acid does not have the dispersing effect of lignin during the preparation process, and Ni3ZnC 0.7 Precursor.

[0075] Figures 2 to 6 The SEM images of the materials prepared in Examples 1 to 5 show that Ni3ZnC 0.7 / ZnO / Ni and lignin-derived carbon are in a loading relationship. At the same time, lignin carbon provides loading sites for metal catalysts and has a carrier effect. In addition, there are a large number of metal catalysts on the composite material lignin-derived carbon prepared in each embodiment, indicating that the material can efficiently load catalysts. Figure 7 This is an SEM image of the composite material prepared in Comparative Example 1. From the figure, it can be seen that many metal catalysts are loaded on the carbon support generated by calcining phthalic acid. However, excessive loading may hinder the adsorption of the substrate during the catalytic process, thereby affecting the catalytic performance. The composite materials prepared in Examples 1 to 5 can see obvious lignin-derived carbon. The biochar can effectively adsorb the substrate to improve the mass transfer efficiency, and can also act as an electron buffer, thereby enhancing the catalytic performance of the composite material.

[0076] Figure 8 The lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 3 0.7 From the pore size distribution diagram and N2 desorption curve diagram of the ZnO / Ni composite material, it can be seen that the material prepared in the embodiment mainly exists in a mesoporous form (as shown in Table 1), and Example 1 has a certain microporous structure, which is beneficial to the adsorption of the substrate. At the same time, the material prepared in Example 1 also has the largest specific surface area; from the N2 desorption curve diagram, it can be seen that the composite material prepared in the embodiment belongs to the classic type IV hysteresis regression line.

[0077] Figure 9 The lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 3 0.7 Raman spectrum of / ZnO / Ni composite material. It can be seen from the figure that the G peak intensity of the prepared composite material is greater than the D peak, indicating that the degree of graphitization of the composite material is high, and the degree of graphitization of the prepared lignin-derived carbon is good. A higher degree of graphitization can improve the electron transfer, structural stability, selectivity and active site efficiency of the composite material.

[0078] Figure 10 The lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 3 0.7 Infrared thermal imaging of the ZnO / Ni composite material. The composite material was irradiated with a 500W xenon lamp and tested using an infrared thermal imager. The image shows that Example 1 reached a temperature of 123°C in 152 seconds, while the materials of the other examples also reached temperatures above 90°C, demonstrating that the composite materials prepared in Examples 1-3 all exhibited excellent light-to-heat conversion performance.

[0079] Figure 11 and Figure 12 The lignin-derived carbon / Ni3ZnC prepared in Example 1 0.7 Transmission electron microscope image and element distribution diagram of the / ZnO / Ni composite material. It can be seen from the figure that the particle size of the composite material prepared in Example 1 is about 10.48nm under transmission electron microscope. The lattice fringes at ABC represent ZnO, Ni and Ni3ZnC respectively through high-power transmission electron microscope. 0.7 , and these three phases form a heterojunction with Ni as the center. The metallic properties of Ni are conducive to the rapid transfer of electrons in the catalytic system. The heterojunction can transfer photogenerated electrons more efficiently, thereby increasing the overall reaction rate. Figure 12 It can be seen that the distribution of Zn, Ni, C, and O in the composite material conforms to the element distribution law of the composite material.

[0080] Figure 13The lignin-derived carbon / Ni3ZnC prepared in Example 1 0.7 / ZnO / Ni composite material hydrogen production performance diagram. As shown in the figure, the prepared material produces hydrogen under the effects of ethanol (50ml 10% volume concentration of ethanol aqueous solution, without cellulose), cellulose (50ml, obtained by mixing 0.5g cellulose and pure water as solvent) and ethanol and cellulose mixture (50ml, obtained by mixing 0.5g cellulose and 10% volume concentration of ethanol aqueous solution) (reaction temperature is 473K). It can be seen that when the substrate cellulose is 0.5g, neither ethanol nor cellulose alone has a better effect than the combination of the two. Adding an appropriate amount of ethanol to the substrate can enhance the hydrogen evolution effect of the system. The upper right corner is a comparison of the substrate before and after catalysis. It can be seen that after the reaction is completed, the material can completely react with cellulose.

[0081] Figure 14 The lignin-derived carbon / Ni3ZnC prepared in Examples 1 to 7 0.7 / ZnO / Ni composite material and the hydrogen production performance diagram of the composite material prepared in comparative example 1 (the substrates were all 50ml 0.5g cellulose and 10% ethanol aqueous solution mixed and reacted at 473K for 2 hours). As shown in the figure, the material prepared in Example 1 has the best performance compared to the materials in Examples 2 and 3, thanks to the appropriate ratio of Ni and Zn. However, too high a ratio of Ni and Zn will lead to stronger Zn-O bond interaction, thereby limiting electron transfer, resulting in reduced catalytic performance of the composite material and affecting the electron density around NiZn. The unbalanced electron density will destroy the interaction with the reactants, resulting in a reduction in the catalytic effect. Examples 4 and 5 have low catalytic performance due to the fact that the catalyst metal composition and the carrier effect of lignin carbon are not obvious due to the excessive and insufficient addition of lignin. Examples 6 and 7 have roughly the same preparation process parameters as Example 1, so the catalyst structures obtained are also roughly the same, and the hydrogen production performance is similar to that of Example 1. The composite material prepared in comparative example 1 has a low catalytic performance due to the absence of Ni3ZnC 0.7 phase, while other examples are made of Ni3ZnC 0.7 / ZnO / Ni three phases, especially in Example 1, there is a ternary heterojunction to improve the transfer and transmission efficiency of electrons, thereby making the catalyst performance good. Therefore, Comparative Example 1 may have poor catalytic performance because the two phases composed of Ni and ZnO alone do not play a good combination role.

[0082] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A high-load lignin-derived carbon / Ni3ZnC 0.7 A method for preparing a / ZnO / Ni ternary heterojunction composite material, characterized in that: The following steps are involved: (1) The lignin alcohol solution and the mixed salt solution of zinc salt and nickel salt are mixed evenly, the precipitant solution is added dropwise, and then water is added. The mixture is heated for reaction, washed, and dried to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite material precursor; (2) Lignin-derived carbon / Ni3ZnC 0.7 The precursor of the / ZnO / Ni composite material was calcined to obtain lignin-derived carbon / Ni3ZnC 0.7 / ZnO / Ni composite materials; In step (1), the ratio of lignin, zinc salt and nickel salt is 1.5-2.5 g: 5-10 mmol: 5-10 mmol; The molar ratio of the precipitant, the zinc salt and the nickel salt is 5-8:0.5-2:0.5-2.

2. A high-load lignin-derived carbon / Ni3ZnC according to claim 1 0.7 A method for preparing a / ZnO / Ni ternary heterojunction composite material, characterized in that: In step (1), the ratio of lignin, zinc salt and nickel salt is 2g:5-10mmol:5-10mmol; The molar ratio of the precipitant, the zinc salt and the nickel salt is 7-8:0.5-1:0.5-1.

3. A high-load lignin-derived carbon / Ni3ZnC according to claim 1 0.7 A method for preparing a / ZnO / Ni ternary heterojunction composite material, characterized in that: The heating reaction temperature in step (1) is 60-100°C and the time is 40-120 minutes; The calcination temperature in step (2) is 450-550°C and the calcination time is 1-3 hours; The heating rate of the calcination in step (2) is 1 to 10°C / min.

4. A high-load lignin-derived carbon / Ni3ZnC according to claim 3 0.7 A method for preparing a / ZnO / Ni ternary heterojunction composite material, characterized in that: The heating reaction temperature in step (1) is 80-90°C and the reaction time is 60-120 minutes; The calcination temperature in step (2) is 500-550° C., the calcination time is 1-3 h, and the heating rate is 3-6° C. / min.

5. A high-load lignin-derived carbon / Ni3ZnC according to claim 1 0.7 A method for preparing a / ZnO / Ni ternary heterojunction composite material, characterized in that: The precipitant solution in step (1) is at least one of ammonia water, potassium hydroxide solution and sodium hydroxide solution; the concentration of the precipitant solution is 5 to 9 mol / L; The concentration of the lignin alcohol solution in step (1) is 12.5 to 62.5 mg / mL; the lignin is at least one of alkali lignin, sulfate lignin, lignin sulfonate and enzymatic lignin; The concentration of the mixed salt solution of zinc salt and nickel salt in step (1) is 0.5-1 mol / L; the zinc salt in step (1) is at least one of zinc nitrate, zinc acetate, zinc carbonate, zinc chloride and zinc oxalate; The nickel salt in step (1) is at least one of nickel nitrate, nickel acetate, nickel carbonate and nickel chloride.

6. A high-load lignin-derived carbon / Ni3ZnC according to claim 5 0.7 A method for preparing a / ZnO / Ni ternary heterojunction composite material, characterized in that: The concentration of the precipitant solution in step (1) is 5 to 8 mol / L; The concentration of the lignin alcohol solution in step (1) is 37.5-62.5 mg / mL; The concentration of the mixed brine solution of the zinc salt and nickel salt in step (1) is 0.75 to 1 mol / L.

7. A high-load lignin-derived carbon / Ni3ZnC according to claim 1 0.7 A method for preparing a / ZnO / Ni ternary heterojunction composite material, characterized in that: The alcohol solvent in the lignin alcohol solution in step (1) is anhydrous ethanol; The volume ratio of the water added in step (1) to the precipitant solution is (0-30):10, and the volume of water is not 0; The calcination atmosphere in step (2) is nitrogen.

8. A high-load lignin-derived carbon / Ni3ZnC prepared by the preparation method according to any one of claims 1 to 7 0.7 / ZnO / Ni ternary heterojunction composite material.

9. The high-load lignin-derived carbon / Ni3ZnC according to claim 8 0.7 Application of / ZnO / Ni ternary heterojunction composite materials in the field of photothermal catalysis.

10. The application according to claim 9, characterized in that: The application is photothermal catalytic reforming of cellulose to produce hydrogen.

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