Electrocatalysts and preparation, application and cogeneration of electrical energy, hydrogen from biomass-derived aldehyde fuel cells

Abstract

The application discloses an electrocatalyst and preparation, application and biomass-derived aldehyde fuel cell for generating electric energy and hydrogen synchronously. Specifically, the application relates to preparation of an electrocatalyst for efficiently catalyzing hydrogen production by oxidizing aldehyde groups and construction of a biomass-derived aldehyde fuel cell for synchronously generating electric energy and hydrogen. The fuel cell realizes a high output power density (173.5 mW / cm 2 ), a high Faraday efficiency (close to 100%) and a fast hydrogen production rate (1.96 mmol / cm 2 / h) at room temperature, which is at a leading level in the existing research. In addition, in the process of generating electric energy, biomass-derived aldehydes are oxidized into corresponding carboxylic acid compounds at the anode, the process is carried out at room temperature and normal pressure, and the reaction is flexible and controllable, so that the application has higher safety and economy compared with traditional aldehyde oxidation technology. In the fields of generating electric energy, producing hydrogen and biomass conversion, the application has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of biomass chemical engineering, specifically relating to an electrocatalyst and a biomass-derived aldehyde fuel cell for the preparation, application, and co-production of electricity and hydrogen. Background Technology

[0002] Hydrogen energy is a crucial component of future national energy systems, with applications in oil refining hydrogenation, ammonia / methanol synthesis, hydrogen fuel cells, and hydrogen metallurgy. In China, annual hydrogen production is increasing year by year; however, most hydrogen is derived from fossil fuels, and the production process emits large amounts of carbon dioxide and consumes non-renewable resources such as coal and natural gas, contradicting the concept of sustainable development. Therefore, there is an urgent need to develop green hydrogen production technologies based on renewable energy sources.

[0003] Electrolysis of water is a green and safe hydrogen production technology, consisting of two half-reactions: the oxygen evolution reaction (OER) at the anolyte and the hydrogen evolution reaction (HER) at the cathode. A major factor limiting the development of water electrolysis for hydrogen production is the slow kinetics and high overpotential of the OER at the anolyte, which significantly increases the electricity cost of hydrogen production, and the oxygen produced at the anolyte has low added value. In recent years, researchers have used the oxidation reactions of various biomass and their derivatives (organic substrates) to replace the OER, which can reduce the overpotential of the anolyte reaction, slightly reduce the electricity consumption of hydrogen production, and simultaneously produce some high-value-added chemicals. Zhou et al. (Angew. Chem. Int. Ed. 2021, 60, 8976-8982) used a manganese-doped cobalt hydroxide (MnCoOOH) anolyte catalyst to selectively electrocatalyze the conversion of lignin derivatives to carboxylates, while simultaneously coupling the cathode HER at 1.5V. RHE The hydrogen production rate at the given potential is 1.41 mmol / cm². 2 / h. Cui et al. (J.Am.Chem.Soc.2021,143,9429-9439) used nitrogen-doped carbon nanotubes (Pt1 / N-CNTs) with atomically dispersed Pt-N3C1 active sites to electrocatalyze the fracture of C in lignin model compounds. α -C β The catalyst is coupled to the cathode HER. Miao et al. (Appl. Catal., B, 2023, 336, 122937) used an Ir single-atom electrocatalyst (Ir-NiFeO@NF) to electrocatalyze the conversion of lignocellulose to carboxylic acid, while simultaneously coupling the cathode HER. The hydrogen production rate was 0.45 mmol / cm² at an applied voltage of 1.5 V. 2 / h.

[0004] Although the technology of hydrogen production via anodic biomass oxidation coupled with cathode has made some progress, compared with the traditional total water splitting reaction, this system can only slightly reduce power consumption. The applied voltage is usually greater than 1.5V, which still requires a large amount of power, severely restricting its commercial application. Therefore, there is an urgent need to develop a more energy-efficient hydrogen production technology. Summary of the Invention

[0005] To address the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a method for preparing an electrocatalyst.

[0006] Another object of the present invention is to provide an electrocatalyst prepared by the above-described preparation method.

[0007] Another object of the present invention is to provide the application of the above-mentioned electrocatalyst in fuel cells.

[0008] Another object of the present invention is to provide a biomass-derived aldehyde fuel cell that co-generates electricity and hydrogen.

[0009] The fuel cell provided by this invention can oxidize biomass-derived aldehydes into carboxylic acid compounds, simultaneously generating electricity and hydrogen. Compared with traditional water electrolysis for hydrogen production, this invention is an electrocatalytic hydrogen production system that does not require electrical energy input and can output electrical energy, greatly reducing the energy consumption of hydrogen production. Furthermore, the biomass-derived aldehyde fuel cell of this invention can operate at room temperature (25°C) and has a high output power density (173.5 mW / cm³). 2 ) and a relatively fast hydrogen production rate (1.96 mmol / cm²) 2 This invention has good versatility and broad application prospects in the fields of power generation, hydrogen production, and biomass conversion. Various biomass-derived aldehydes (including benzaldehyde, furfural, p-methoxybenzaldehyde, 3,4-dimethoxybenzaldehyde, etc.) can be used in the fuel cell of this invention to simultaneously achieve power generation and hydrogen production.

[0010] The objective of this invention is achieved through the following technical solution:

[0011] A method for preparing an electrocatalyst includes the following steps:

[0012] (1) At least one nanoparticle of copper, silver and gold is prepared on a substrate by electrodeposition to obtain a substrate loaded with nanoparticles;

[0013] (2) The substrate loaded with nanoparticles in step (1) is activated by cyclic voltammetry (CV), and then electrochemical reduction or reduction by reducing agent is performed to obtain the substrate loaded with metal oxide nanoparticles.

[0014] The metal oxide nanoparticles are metal oxides corresponding to at least one of the elements copper, silver and gold.

[0015] (3) The substrate loaded with metal oxide nanoparticles in step (2) is doped with metal elements and then electrochemically reduced or reduced with a reducing agent to obtain a substrate loaded with metal element-doped metal oxide nanoparticles, i.e., an electrocatalyst.

[0016] The metal elements doped in it are different from those in metal oxide nanoparticles.

[0017] Preferably, the substrate in step (1) is at least one of copper foam, nickel foam, zinc foam, aluminum foam, carbon felt, carbon paper, and carbon cloth.

[0018] Preferably, before electrodeposition, the substrate in step (1) is washed sequentially with acetone, hydrochloric acid solution, anhydrous ethanol and water, and the washing method is ultrasonic washing.

[0019] Preferably, the electrolyte used in the electrodeposition method in step (1) is at least one of CuSO4, CuCl2, Cu(NO3)2, AgNO3 and AuBr3, with a concentration of 0.01 to 3 mol / L.

[0020] More preferably, the electrolyte further contains 0.001–2 mol / L ethanol and 0.001–4 mol / L H2SO4.

[0021] Preferably, the electrodeposition process in step (1) is carried out in a three-electrode system, wherein the constant current is -500 to -1 mA / cm. 2 The electrodeposition time is 10–5000 s.

[0022] More preferably, the working electrode of the three-electrode system is the substrate described in step (1), the reference electrode is Ag / AgCl, and the counter electrode is a graphite rod.

[0023] Preferably, the cyclic voltammetry activation in step (2) is performed in a three-electrode system, with a scan range of -1.0 to 2.0 V. RHE The scan rate is 0.5–100 mV / s, and the cycle is 1–100 times.

[0024] More preferably, the working electrode of the three-electrode system is the substrate loaded with nanoparticles in step (1), the reference electrode is Hg / HgO, and the counter electrode is a graphite rod.

[0025] Preferably, the electrolyte activated by cyclic voltammetry in step (2) is at least one of KOH, NaOH, Na2CO3, NaHCO3, K2CO3 and KHCO3, with a concentration of 0.05 to 5 mol / L.

[0026] Preferably, the electrochemical reduction in step (2) is carried out in a three-electrode system activated by cyclic voltammetry, wherein the constant potential is -3.0 to 0.4 V. RHE The restoration time is 10 to 3600 seconds.

[0027] Preferably, the reducing agent in step (2) is at least one of NaBH4, LiBH4 and Zn(BH4)2; specifically, the substrate of loaded nanoparticles activated by cyclic voltammetry is placed in a 0.001-3 mol / L aqueous solution of the reducing agent for impregnation and reduction, and the reduction time is 10-5000 s.

[0028] Preferably, the method of metal element doping in step (3) is as follows: placing the substrate loaded with metal oxide nanoparticles in a metal salt solution of 0.05 to 50 mmol / L for 10 to 240 min; and doping the metal element into the metal oxide nanoparticles.

[0029] More preferably, the metal salt solution is at least one of AgNO3, RuCl3, AuBr3, PdCl2, Pt(NO3)2, Fe(NO3)3 and Co(NO3)2.

[0030] Preferably, the doped metal element in step (3) is at least one of Ag, Ru, Au, Pd, Pt, Fe and Co.

[0031] Preferably, the electrochemical reduction in step (3) is carried out in a three-electrode system, wherein the constant potential is -3.0 to 0.4 V. RHE The restoration time is 10 to 3600 seconds.

[0032] More preferably, the electrolyte of the three-electrode system is at least one of KOH, NaOH, Na2CO3, NaHCO3, K2CO3 and KHCO3, with a concentration of 0.05 to 5 mol / L; the working electrode is a substrate of metal oxide nanoparticles soaked in a metal salt solution, the reference electrode is Hg / HgO, and the counter electrode is a graphite rod.

[0033] Preferably, the reducing agent in step (3) is at least one of NaBH4, LiBH4, and Zn(BH4)2. The electrocatalyst precursor to be reduced is placed in a 0.001–3 mol / L aqueous solution of the reducing agent for impregnation and reduction, with a reduction time of 10–3600 s.

[0034] An electrocatalyst prepared by the above method.

[0035] The above-mentioned electrocatalyst is used in fuel cells.

[0036] A biomass-derived aldehyde fuel cell that co-generates electricity and hydrogen includes an anode, a cathode, an anode electrolyte, a cathode electrolyte, a membrane, and wires; wherein the anode is supported with the aforementioned electrocatalyst; and the anode electrolyte contains biomass-derived aldehyde at a concentration of 1–1000 mmol / L.

[0037] Preferably, in the biomass-derived aldehyde fuel cell, the anode and cathode are separated by a membrane to form an anode chamber containing an anode electrolyte and a cathode chamber containing a cathode electrolyte.

[0038] Preferably, the diaphragm is a Nafion membrane.

[0039] Preferably, the biomass-derived aldehyde fuel cell further includes a circulation pump, which continuously replenishes the anolyte and catholyte to the anolyte and catholyte, respectively.

[0040] Preferably, the wires connect the anode and cathode to the external circuit respectively, that is, the battery anode is connected to the external load and the battery cathode is connected to the external load.

[0041] Preferably, the electrode material in the cathode is carbon felt.

[0042] Preferably, the biomass-derived aldehyde in the anolyte is at least one selected from benzaldehyde, p-methoxybenzaldehyde, 3,4-dimethoxybenzaldehyde, furfural, 5-hydroxymethylfurfural, and formaldehyde.

[0043] Preferably, the concentration of biomass-derived aldehyde in the anolyte is 1–1000 mmol / L, more preferably 10–500 mmol / L, and most preferably 30–200 mmol / L.

[0044] Preferably, the alkali in the anolyte is at least one of NaOH, KOH and ammonia water, and the concentration of the alkali is 0.001 to 8 mol / L, more preferably 0.1 to 4 mol / L, and most preferably 1 to 2 mol / L.

[0045] Preferably, the operating temperature of the biomass-derived aldehyde fuel cell is 5–98°C.

[0046] Preferably, the cathode electrolyte comprises a ferric salt with a concentration of 0.01–4 mol / L, an acid solution with a concentration of 0.01–6 mol / L, and a cathode regeneration oxidant.

[0047] More preferably, the ferric salt is at least one of ferric chloride, ferric sulfate, and ferric nitrate; the acid solution is at least one of hydrochloric acid solution, sulfuric acid solution, and nitric acid solution; and the cathode regeneration oxidant is at least one of nitric acid, oxygen, hydrogen peroxide, and potassium permanganate.

[0048] More preferably, when the cathode regeneration oxidant is nitric acid, its concentration in the cathode electrolyte is 0.01–8 mol / L; when the cathode regeneration oxidant is oxygen, its flow rate is 10–100 mL / min; when the cathode regeneration oxidant is hydrogen peroxide, its concentration is 0.2–10 mol / L; and when the cathode regeneration oxidant is potassium permanganate, its concentration is 0.01–0.5 mol / L.

[0049] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0050] 1. This invention utilizes the prepared electrocatalyst to construct a biomass-derived aldehyde fuel cell, transforming the power-consuming process of electrocatalytic hydrogen production into a power generation process; the anode aldehyde oxidation reaction is combined with the cathode Fe... 3+ Reduced to Fe 2+ The reaction phase coupling enables spontaneous and rapid electron transfer from the anode to the cathode, outputting electrical energy. Simultaneously, the aldehyde group at the anode releases hydrogen gas upon oxidation, thus achieving simultaneous hydrogen production. Compared to traditional water electrolysis for hydrogen production, this invention's hydrogen production process requires no electricity and can generate power to an external load. The battery achieves a high output power density (173.5 mW / cm²) at room temperature (25°C). 2 It has a high Faraday efficiency (close to 100%) and a fast hydrogen production rate (1.96 mmol / cm²). 2 / h), which is at the forefront of existing research.

[0051] 2. The battery constructed using the electrocatalyst prepared in this invention generates electricity while simultaneously oxidizing the biomass-derived aldehyde at the anode into the corresponding acid. This process takes place at room temperature and atmospheric pressure, and the reaction is flexible and controllable. Existing aldehyde oxidation to acid reaction techniques often use air and oxygen under harsh conditions of high temperature and high pressure, or use expensive oxidants. Compared with the above-mentioned traditional technologies, this invention has higher safety and economy. Furthermore, this low-potential aldehyde oxidation reaction of the present invention almost avoids competition from OER, greatly improving the Faraday efficiency (approaching 100%). Attached Figure Description

[0052] Figure 1 Linear sweep voltammetric curves of different types of copper-based catalysts for the electrocatalytic oxidation of benzaldehyde in Example 1.

[0053] Figure 2 Example 2: Ag-Cu at different potentials x (a) Conversion rate and (b) Faraday efficiency of hydrogen production in the O / CF electrocatalytic conversion of benzaldehyde.

[0054] Figure 3 Example 3 is based on Ag-Cux In-situ differential electrochemical mass spectrometry of O / CF electrocatalytic conversion of benzaldehyde and corresponding potential and current signals.

[0055] Figure 4 Example 4 is based on Ag-Cu x Linear scanning voltammetric curves of O / CF electrocatalytic conversion of benzaldehyde, furfural, p-methoxybenzaldehyde, and 3,4-dimethoxybenzaldehyde.

[0056] Figure 5 Example 5 is based on Ag-Cu x Current density-voltage-output power density graph of O / CF biomass-derived aldehyde fuel cell.

[0057] Figure 6 Example 6 is based on Ag-Cu x Time-current density-hydrogen production graph of O / CF biomass-derived aldehyde fuel cell.

[0058] Figure 7 The linear sweep voltammetric curves are for the electrocatalytic oxidation of benzaldehyde using copper-based catalysts with different Ru doping in Examples 7, 1, and 2. Detailed Implementation

[0059] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0060] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available conventional products.

[0061] Example 1: Preparation of a highly efficient copper-based electrocatalyst for the oxidation of biomass-derived aldehydes

[0062] 1. Preparation of copper-based electrocatalyst: (1) Copper foam was ultrasonically washed sequentially with acetone, 3 mol / L HCl solution, anhydrous ethanol and deionized water for 10 min each time. This material is denoted as CF. (2) Copper nanoparticles were loaded onto the copper foam support by electrodeposition. The electrodeposition process was carried out in a three-electrode electrolytic cell (the working electrode was CF, the reference electrode was Ag / AgCl, and the counter electrode was a graphite rod) with a constant current of -20 mA / cm. 2The process lasted for 1000 s, and the electrolyte was a 0.5 mol / L CuSO4 solution (containing 0.1 mol / L ethanol and 0.2 mol / L H2SO4). This material is denoted as Cu / CF. (3) Cyclic voltammetry (CV) was used to activate the material surface to reconstruct it and increase the electrochemical reaction activity area. CV activation was carried out in a three-electrode electrolytic cell (working electrode Cu / CF, reference electrode Hg / HgO, counter electrode graphite rod, electrolyte 1 mol / L KOH solution), with a scan range of -0.1 to 1.2 V. RHE The scan rate was 5 mV / s, and the cycle length was 10 revolutions. After CV activation, electrochemical reduction was performed in the above three-electrode system at a constant potential of -0.3 V. RHE The reduction time is 600 s. This material is designated as Cu. x O / CF. (4) Cu x O / CF was placed in 0.5 mmol / L AgNO3 solution and stirred for 45 min to dope Ag into the material. Electrochemical reduction was then performed in a three-electrode system (working electrode: the prepared material; reference electrode: Hg / HgO; counter electrode: graphite rod; electrolyte: 1 mol / L KOH solution) at a constant potential of -0.3 V. RHE The reduction time is 300 seconds. This material is designated as Ag-Cu. x O / CF.

[0063] 2. Performance testing of copper-based catalysts for the electrocatalytic oxidation of biomass-derived aldehydes: This test was conducted in a three-electrode system (working electrode: copper-based catalyst; reference electrode: Hg / HgO; counter electrode: graphite rod), using a 1 mol / L KOH solution (containing 30 mmol / L benzaldehyde) as the electrolyte, with a scan range of 0–0.5 V. RHE The electrocatalytic performance was tested using linear sweep voltammetry, and the results are as follows: Figure 1 As shown. When the four copper-based catalysts prepared above are used as working electrodes, Ag-Cu x O / CF at 0–0.5V RHE The copper-based catalyst exhibits the largest current response, indicating its highest electrocatalytic activity in oxidizing aldehydes, while CF shows almost no current response, suggesting it lacks electrocatalytic activity. As the preparation process progresses, the electrocatalytic activity of the copper-based catalyst gradually increases. This is due to the increased specific surface area resulting from copper nanoparticle electrodeposition, the increased surface roughness from CV activation, the electrochemical reduction process modulating the valence state of copper to electrocatalytically active zero-valent and monovalent copper, and the enhancement of electrocatalytic activity through silver doping, which strengthens the catalyst's adsorption of reactant molecules.

[0064] Example 2: Ag-Cu x O / CF electrocatalytic conversion of benzaldehyde simultaneously produces aromatic acids and hydrogen.

[0065] Ag-Cu was prepared according to Example 1. x An O / CF electrocatalyst was used for the electrocatalytic conversion of benzaldehyde. The experiment of electrocatalytic oxidation of benzaldehyde to hydrogen was conducted in an H-type electrolytic cell, with the two cells separated by a Nafion membrane. The anolyte was a 1 mol / L KOH solution (containing 30 mmol / L benzaldehyde), and the cathode electrolyte was a 1 mol / L KOH solution. A three-electrode system was used, with the working electrode being Ag-Cu. x The reaction was carried out using O / CF as the reference electrode, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode. The reaction potential was controlled at 0.25V. RHE 0.3V RHE 0.35V RHE 0.4V RHE and 0.45V RHE The conversion rate was determined by high performance liquid chromatography (HPLC), and the hydrogen production Faraday efficiency was determined by gas chromatography (GC). The results are as follows: Figure 2 As shown. By Figure 2 (a) can be seen at 0.4V RHE Previously, the conversion rate of benzaldehyde was close to 100%, but at 0.45V... RHE At this point, the conversion rate of benzaldehyde decreased to only 74.2%, because excessively high potentials lead to over-oxidation of the catalyst, generating more inactive divalent copper. Figure 2 (b) can be seen at 0.35V RHE Previously, the Faraday efficiency of hydrogen production was close to 100%, but at 0.4V... RHE Subsequently, the Faraday efficiency of hydrogen production decreased to only 60-77%, because benzaldehyde tends to be oxidized via a two-electron pathway at higher potentials (producing water rather than hydrogen), thus inhibiting hydrogen production.

[0066] Example 3: Ag-Cu x Mechanism of simultaneous hydrogen production from O / CF electrocatalytic conversion of aromatic aldehydes

[0067] To verify the source of hydrogen produced by the oxidation of benzaldehyde, this invention uses in-situ differential electrochemical mass spectrometry to investigate the reaction mechanism. Ag-Cu was prepared according to Example 1. x O / CF electrocatalyst was used for mechanism verification of the electrocatalytic conversion of benzaldehyde to hydrogen. A three-electrode system was used (working electrode: Ag-Cu). x The electrolyte was 1 mol / L KOD (containing 30 mmol / L benzaldehyde, with D2O as the solvent). The voltage was set to 0.35 V. RHEThe potential was set (lasting 100s), then paused (lasting 200s), and repeated 8 times (totaling 2400s) in 300s cycles, while the generated gas was measured in situ. The test results are as follows. Figure 3 As shown, it can be seen at 0.35V RHE At that time, there was a signal response of H2, but no signals of HD and D2 were captured, which proved that H came from H in benzaldehyde, rather than from potassium hydroxide or water.

[0068] Example 4: Ag-Cu x Electrocatalytic performance of O / CF on different aromatic aldehyde substrates

[0069] Ag-Cu was prepared according to the method in Example 1. x An O / CF electrocatalyst was used for the electrocatalytic conversion of four aromatic aldehydes, including benzaldehyde, furfural, p-methoxybenzaldehyde, and 3,4-dimethoxybenzaldehyde. Linear sweep voltammetry was performed in a three-electrode system (working electrode: Ag-Cu). x The electrode configuration was O / CF, with Hg / HgO as the reference electrode and a graphite rod as the counter electrode. The electrolyte was a 1 mol / L KOH solution (containing 30 mmol / L aromatic aldehydes), and the scan range was 0–0.5 V. RHE The test results are as follows: Figure 4 As shown, all four aromatic aldehydes exhibited significant current responses, indicating that Ag-Cu x O / CF exhibits good electrocatalytic activity for different types of aldehydes. The current response signals of the four aromatic aldehydes, from largest to smallest, are benzaldehyde > furfural > p-methoxybenzaldehyde > 3,4-dimethoxybenzaldehyde. This is because the electron-withdrawing / donating effects of the aromatic ring and substituents affect the reactivity of the aldehyde group.

[0070] Example 5: Construction and Power Generation Performance Testing of Biomass-Derived Aldehyde Fuel Cells

[0071] Ag-Cu was prepared according to the method in Example 1. xAn O / CF electrocatalyst was used as the anode catalyst in a biomass-derived aldehyde fuel cell and loaded in the anode channel inside the cell. Carbon felt was loaded in the cathode channel inside the cell. A Nafion membrane separated the anode and cathode to prevent short circuits. The anode electrolyte was a 2 mol / L KOH solution (containing 30 mmol / L aromatic aldehydes), which was added to the anode tank. The cathode electrolyte was a 1 mol / L acidic FeCl3 solution, which was added to the cathode tank. The anode electrolyte tank was connected to the anode inlet and outlet of the cell, and the cathode tank was connected to the cathode inlet and outlet. The electrolyte circulated between the electrolyte tank and the cell using a pump. The cell operating temperature was 25°C. The anode fuels for the four cells were benzaldehyde, furfural, p-methoxybenzaldehyde, and 3,4-dimethoxybenzaldehyde, respectively. Simultaneously, oxygen was introduced into the cathode tank at a flow rate of 20 mL / min to regenerate the cathode electrolyte. The power generation performance of the cells was tested using the scanning current method, and the results are as follows: Figure 5 As shown, different types of biomass-derived aldehydes can be used in the fuel cells of this invention to generate electricity and produce hydrogen, which proves the universality of this invention.

[0072] Example 6: Hydrogen production rate test of biomass-derived aldehyde fuel cell

[0073] The biomass-derived aldehyde fuel cell constructed according to Example 5, using benzaldehyde as the anode fuel, was tested for its hydrogen production rate during long-term discharge. Anode headspace gas samples (1 mL) were taken at approximately 7 min intervals, and the accumulated hydrogen was quantified by gas chromatography analysis. The test results are as follows: Figure 6 As shown, this battery exhibits a high hydrogen production rate (approximately 1.96 mmol / cm²). 2 / h).

[0074] Example 7: Preparation of a Ru-doped copper-based electrocatalyst for the oxidation of biomass-derived aldehydes

[0075] 1. Preparation of Ru-doped copper-based electrocatalyst: The preparation steps are similar to those in Example 1. The difference is that the 0.5 mol / L AgNO3 solution in step (4) is replaced with a 0.5 mol / L RuCl3 solution, and Cu is added... x O / CF was placed in a 0.5 mmol / L RuCl3 solution and stirred for 45 min to dope Ru into the material. The remaining steps were the same as in Example 1. The resulting material is denoted as Ru-Cu. x O / CF.

[0076] 2. Performance testing of Ru-doped copper-based catalyst for the electrocatalytic oxidation of biomass-derived aldehydes: This test was conducted in a three-electrode system (working electrode: copper-based catalyst; reference electrode: Hg / HgO; counter electrode: graphite rod), using a 1 mol / L KOH solution (containing 30 mmol / L benzaldehyde) as the electrolyte, with a scan range of 0–0.5 V. RHE The electrocatalytic performance was tested using linear sweep voltammetry, and the results are as follows: Figure 7 As shown. Comparing it with the electrocatalysts prepared in Comparative Examples 1 and 2, it can be seen that Ru-Cu... x O / CF at 0–0.5V RHE The Ru-Cu exhibits the largest current response, indicating that it possesses the highest electrocatalytic activity for the oxidation of aldehyde groups. x The electrocatalytic activity of O / CF-1 was second highest, while that of Ru-Cu / CF was the lowest. This is because CV activation increases the surface roughness of the material, the electrochemical reduction process modulates the valence state of copper to electrocatalytically active zero-valent and monovalent copper, and Ru doping can enhance the adsorption behavior of the catalyst for reactant molecules, thereby improving the electrocatalytic reaction activity. Furthermore, Example 7 involved electrodeposition, CV activation, and electroreduction followed by Ru doping, while Comparative Example 2 involved simultaneous Ru doping during electrodeposition, followed by CV activation and electroreduction. The method of Example 7 is superior to that of Comparative Example 2, Ru-Cu... x O / CF ratio Ru-Cu x O / CF-1 exhibits higher electrocatalytic activity.

[0077] Comparative Example 1: Preparation of Unactivated Copper-Based Catalysts by Electrodeposition Simultaneous Ru Doping

[0078] 1. Preparation of copper-based electrocatalyst: (1) Copper foam was ultrasonically washed sequentially with acetone, 3 mol / L HCl solution, anhydrous ethanol and deionized water for 10 min each time. This material is denoted as CF. (2) Copper nanoparticles were loaded onto the copper foam support by electrodeposition and Ru was simultaneously doped. The electrodeposition process was carried out in a three-electrode electrolytic cell (the working electrode was CF, the reference electrode was Ag / AgCl, and the counter electrode was a graphite rod) with a constant current of -20 mA / cm. 2 The reaction was carried out for 1000 s, with the electrolyte being a 0.5 mol / L CuSO4 solution (containing 0.1 mol / L ethanol, 0.2 mol / L H2SO4, and 0.5 mol / L RuCl3). This material is designated as Ru-Cu / CF.

[0079] 2. Performance testing of copper-based catalysts for the electrocatalytic oxidation of biomass-derived aldehydes: This test was conducted in a three-electrode system (working electrode: copper-based catalyst; reference electrode: Hg / HgO; counter electrode: graphite rod), using a 1 mol / L KOH solution (containing 30 mmol / L benzaldehyde) as the electrolyte, with a scan range of 0–0.5 V. RHE The electrocatalytic performance was tested using linear sweep voltammetry, and the results are as follows: Figure 7 As shown.

[0080] Comparative Example 2: Preparation of copper-based catalysts by simultaneous Ru doping via electrodeposition and CV activation

[0081] 1. Preparation of copper-based electrocatalysts: Steps (1) and (2) are the same as in Comparative Example 1. (3) CV activation is used to reconstruct the surface of the material, increasing the active area for electrochemical reactions. CV activation is carried out in a three-electrode electrolytic cell (the working electrode is the prepared material, the reference electrode is Hg / HgO, the counter electrode is a graphite rod, and the electrolyte is a 1 mol / L KOH solution), with a scan range of -0.1 to 1.2 V. RHE The scan rate was 5 mV / s, and the cycle length was 10 revolutions. After CV activation, electrochemical reduction was performed in the above three-electrode system at a constant potential of -0.3 V. RHE The reduction time is 600 s. This material is designated as Ru-Cu. x O / CF-1.

[0082] 2. Performance testing of copper-based catalysts for the electrocatalytic oxidation of biomass-derived aldehydes: This test was conducted in a three-electrode system (working electrode: copper-based catalyst; reference electrode: Hg / HgO; counter electrode: graphite rod), using a 1 mol / L KOH solution (containing 30 mmol / L benzaldehyde) as the electrolyte, with a scan range of 0–0.5 V. RHE The electrocatalytic performance was tested using linear sweep voltammetry, and the results are as follows: Figure 7 As shown.

[0083] Comparative Example 3: Furfural fuel cell based on H-PdCu ANs

[0084] H-PdCu ANs were prepared by reducing fresh K₂Pd(CN)₄ / CuCl₂ cyano gel with NaBH₄. First, 3.0 mL of 0.05 mol / L K₂Pd(CN)₄ solution and 3.0 mL of 0.05 mol / L CuCl₂ solution were ultrasonically mixed at 30 °C to produce a blue K₂Pd(CN)₄ / CuCl₂ cyano gel. Freshly prepared NaBH₄ aqueous solution (6 mL, 0.033 mg / mL) was then added dropwise. The gel color immediately changed from blue to black. The solution was stirred continuously for 30 min, and then continuously stirred at 30 °C for 9 h. The derived black powder was washed several times with 0.5 mol / L H₂SO₄, water, and ethanol, and then vacuum dried overnight at 60 °C.

[0085] A biomass oxidation / oxygen reduction electrocatalytic system was assembled using carbon cloth-supported H-PdCu ANs as both anode and cathode catalysts. A 1 mol / L KOH solution (containing 0.2 mol / L furfural) was used as the anode electrolyte, and a 1 mol / L KOH solution was used as the cathode electrolyte, requiring continuous oxygen supply. The power generation performance of the battery was tested using the scanning current method, and the test results are listed in Table 1.

[0086] Comparative Example 4: Pt-Cu-based Acid-Base Furfural Fuel Cell

[0087] Pt-Cu nanorods on copper foam were prepared via an electrochemical co-reduction method. The electroreduction process was carried out in a two-electrode system at a constant voltage of 3V for 30 min, yielding Cu(OH)₂ loaded on the copper foam, which served as the cathode. A platinum sheet was used as the anode, and 50 mL of a 1 mol / L KOH / 0.1 mmol / L H₂PtCl₆ mixed solution was used as the electrolyte. After the reaction, the obtained Pt-Cu nanorods loaded on the copper foam were washed with distilled water and then stored in ethanol.

[0088] 1.6 mg of commercial 20 wt% Pt / C powder was dispersed in a mixed solution containing 100 μL distilled water, 100 μL isopropanol, and 10 μL 5 wt% Nafion solution, and sonicated (40 kHz) for at least 1 h to form a uniform ink. The ink was then poured onto a sheet of carbon paper (1 cm × 1 cm) under an infrared heating lamp.

[0089] Assemble an acid-base furfural fuel cell, in which Pt-Cu (1cm×1cm) supported on copper foam and Pt / C (1cm×1cm) supported on carbon paper serve as the anode and cathode, respectively, using K... +An exchange membrane was used for separation (previously converted from Nafion N115 PEM in 1 mol / L KOH solution at 60℃). The cathode electrolyte was 1 mol / L H2SO4, and the anolyte was 1 mol / L KOH / 0.2 mol / L furfural, with the flow rate controlled at 150 mL / min using a peristaltic pump. Two TA1 type titanium metal plates, engraved with single serpentine flow channels, served as bipolar plates. The power generation performance of the battery was tested using the scanning current method, and the test results are listed in Table 1.

[0090] Comparative Example 5: Lignin Fuel Cell Based on CoS@NF

[0091] CoS@NF was prepared by electrochemical deposition. Nickel foam was cut into 2.5 × 2.5 cm pieces. 2 As the working electrode, it was ultrasonically washed sequentially with dilute hydrochloric acid, anhydrous ethanol, and ultrapure water before electrochemical deposition. To prepare the CoS@NF anode, 50 ml of a mixed aqueous solution containing 2.5 mmol / L CoSO4·7H2O and 25 mmol / L thiourea was prepared. Electrochemical deposition was performed using a three-electrode system, with nickel foam as the working electrode, and Ag / AgCl and Pt mesh as the reference and counter electrodes, respectively. Electrochemical deposition was carried out at a constant potential of -1.0 V (relative to Ag / AgCl) for 30 min.

[0092] The lignin fuel cell consists of two graphite bipolar plates, a square flow chamber (20 mm wide × 20 mm long × 2 mm deep), and two copper plates as current collectors. The square flow chamber is filled with nickel foam (anode) and carbon felt (cathode). A Nafion 117 membrane is placed between the two graphite plates. Anode and cathode electrolytes are fed into and out of the square flow chamber via a peristaltic pump. 100 mg of lignin was dissolved in 50 mL of 3 mol / L KOH solution to obtain a lignin solution with a concentration of 2 g / L, which was used as the anolyte. A 0.37 mol / L (VO₂)₂SO₄ solution was used as the cathode electrolyte. The power generation performance of the battery was tested using the scanning current method, and the test results are listed in Table 1.

[0093] Comparative Example 6: Furfural Fuel Cell Based on Ag2O@Ni Foam

[0094] Ag₂O@Ni foam was prepared by spraying silver oxide powder onto nickel foam. 100 mg of Ag₂O powder, 10 mg of PVDF, and 10 mg of carbon powder were weighed and mixed thoroughly in an agate mortar. Then, 1 mL of N-methylpyrrolidone was added, and the mixture was ground for 1 hour. The resulting slurry was then evenly coated onto three pre-cut 1 cm × 1 cm pieces of nickel foam and placed in an oven to dry overnight at 70 °C. The Ag₂O loading of the prepared Ag₂O@Ni foam was approximately 33 mg / cm³. 2 .

[0095] The fuel cell mainly consists of two graphite plates (each with a 1cm × 1cm square chamber etched in the middle) and two conductive copper plates. Ag2O@Ni foam and carbon felt are embedded in the square chamber of the graphite plates as the anode and cathode, respectively. A Nafion 115 membrane is sandwiched between the two graphite plates. By connecting the battery device to external anode and cathode containers, electrolyte storage and redox reactions are performed. The furfural fuel cell can generate electricity and oxidize furfural to produce furanic acid. The electrolyte flows between the square chamber of the graphite plate and the external electrolyte storage container at a flow rate of 98 mL / min using a peristaltic pump. The electrolyte storage container is placed in a water bath to maintain the temperature (40℃), and the graphite plates are heated to the test temperature (40℃) using an electric heating rod. Both the cathode and anode electrolytes are 30 mL. O2 is continuously introduced into the cathode electrolyte to receive electrons transferred from ABTS and laccase. The power generation performance of the battery is tested using the scanning current method, and the test results are listed in Table 1.

[0096] Comparative Example 7: Furfural Fuel Cell Based on Rh1Cu

[0097] A piece of copper foam (3cm × 4cm) was calcined at 350℃ for 2 hours at a heating rate of 5℃ / min. Then, in a two-electrode system, using nickel foam (3cm × 4cm) as the anode, electrochemical reduction was performed in 1mol / L KOH solution at a constant -3.0V for 30 minutes to obtain a copper electrocatalyst. A piece of copper electrocatalyst (3cm × 4cm) was immersed in 100mL of an aqueous solution containing 25μmol RhCl3 and stirred at 500rpm for 20 minutes to induce a displacement reaction, yielding a Rh1Cu electrocatalyst.

[0098] Co 1-x Ni x(OH)₂ was prepared by electrodeposition in a three-electrode system, using 50 mL of a 0.1 mol / L Ni(NO₃)₂·6H₂O / Co(NO₃)₂·6H₂O mixed solution as the electrolyte and Ag / AgCl as the reference electrode. Before use, the nickel foam was ultrasonically cleaned for 15 min each in 1 mol / L HCl solution, ethanol, and deionized water. To prepare a high-quality loading (~50 mg / cm³), [further details are needed]. 2 The electrodes underwent multiple consecutive electrodepositions, using two identical (2.5cm × 4cm) nickel foam sheets as the working and counter electrodes, respectively. A constant current density of -10mA / cm² was maintained. 2 Under these conditions, electrodeposition was performed four times, each lasting 3000 s. To ensure uniform deposition, the electrodes were inverted, and the electrolyte was replaced after each electrodeposition process. After electrodeposition, the electrodes were washed with deionized water to remove residual metal ions. Then, the obtained Co was... 1-x Ni x The (OH)2 electrode was activated by constant current (100mA) charge-discharge (5 cycles).

[0099] Constructing a system based on Rh1Cu(-)‖Co 0.2 Ni 0.8 (OH)2(+) furfural fuel cell. A piece of Rh1Cu catalyst was cut into 1.5cm pieces. 2 It is pressed into a 2cm x 2cm nickel foam. Co is used. 0.2 Ni 0.8 (OH)₂ (2cm×2cm) electrode (mass loading of ~50mg / cm²) 2 As the cathode, two clean, identically sized pieces of nickel foam are clamped together to prevent electrode material from detaching. Before assembly, the Rh1Cu catalyst is heated to -1.0V. Hg / HgO Electroreduction was performed in 1 mol / L KOH solution for 300 s to remove any oxides that might form on the catalyst surface. Then, the Rh1Cu catalyst, Nafion 117 film, and Co were... 0.2 Ni 0.8 (OH)₂ is stacked and compacted layer by layer. The flow channel area is 4 cm². 2 The electrolyte was circulated using a peristaltic pump. The cathode electrolyte was a 1 mol / L KOH solution at a flow rate of 15 mL / min. 2 mol / L KOH (15 mL / min) and 0.2 mol / L furfural (15 mL / min) were flowed through a three-way valve to synthesize the anolyte (1 mol / L KOH + 0.1 mol / L furfural) at a flow rate of 30 mL / min. The battery's power generation performance was tested using the scanning current method, and the results are listed in Table 1.

[0100] Comparative Example 8: Alkali Lignin Fuel Cell Based on CoS@Ni Foam

[0101] CoS@Ni foam was prepared using the method described in Comparative Example 5.

[0102] The battery body consists of two graphite plates serving as the anode and cathode, with a copper plate mounted on the graphite plates as the current collector. Each graphite plate has a square flow chamber (1 cm wide × 1 cm long × 0.2 cm deep) etched in the center. On the anode side, prepared CoS@Ni foam was cut into 1 cm × 1 cm pieces and filled into the flow chamber. On the cathode side, the flow chamber was filled with carbon foam. A Nafion 115 membrane was sandwiched between the two graphite plates, separating the anode and cathode. Two containers containing anolyte and catholyte electrolytes (referred to as the anode reactor and cathode reactor) were connected to the flow chamber via pipes. The electrolyte was pumped into the battery and then circulated back to the reactors. The graphite plates were heated to the test temperature (40°C) using an electric heating rod. The battery's power generation performance was tested using the scanning current method, and the results are listed in Table 1.

[0103] Table 1 is a comprehensive comparison of the above embodiments and comparative examples in terms of operating temperature, hydrogen production, and maximum power density.

[0104] Table 1. Comprehensive Comparison of Various Biomass Fuel Cell Systems

[0105]

[0106] Comparing all the examples and comparative examples, it is evident that the battery with the best power generation performance is the biomass-derived aldehyde fuel cell system constructed using benzaldehyde as a raw material in Example 5, achieving a maximum power density of 173.5 mW / cm³ at room temperature. 2 The power density is significantly higher than that of comparative examples 3-8. Furthermore, the biomass-derived aldehyde fuel cell of this invention can use various aldehyde compounds as anode fuels and achieves excellent output power density and simultaneous hydrogen production, further verifying the universality of this invention. When furfural, p-methoxybenzaldehyde, and 3,4-dimethoxybenzaldehyde are used as anode fuels, the maximum power density at room temperature can reach 162.9 mW / cm³, respectively. 2 138.5mW / cm 2 104.9mW / cm 2 The differences in the power generation performance of different aldehyde compounds are due to the differences in the electron-donating / withdrawing effects of aromatic rings and substituents.

[0107] As can be seen, this invention prepares a highly efficient electrocatalyst (Ag-Cu) for the oxidation of aldehydes to hydrogen. xA biomass-derived aldehyde fuel cell (BFC) capable of simultaneously generating electricity and hydrogen was constructed using an O / CF method. This cell achieved a high output power density (173.5 mW / cm²) at room temperature (25°C). 2 This invention is at the forefront of existing research. Furthermore, while generating electricity, the biomass-derived aldehydes at the anode are oxidized into corresponding carboxylic acid compounds. This process is carried out at room temperature and atmospheric pressure, and the reaction is flexible and controllable, offering higher safety and economy compared to traditional aldehyde oxidation technologies.

[0108] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an electrocatalyst for the anode of a biomass-derived aldehyde fuel cell, characterized in that, Includes the following steps: (1) At least one nanoparticle of copper, silver and gold is prepared on a substrate by electrodeposition to obtain a substrate loaded with nanoparticles; (2) The substrate loaded with nanoparticles in step (1) is activated by cyclic voltammetry and then electrochemically reduced or reduced by a reducing agent to obtain the substrate loaded with metal oxide nanoparticles. The metal oxide nanoparticles are metal oxides corresponding to at least one of the elements copper, silver and gold. (3) The substrate loaded with metal oxide nanoparticles in step (2) is doped with metal elements and then electrochemically reduced or reduced with a reducing agent to obtain a substrate loaded with metal element-doped metal oxide nanoparticles, i.e., an electrocatalyst. The metal elements doped in it are different from those in metal oxide nanoparticles. The method for metal element doping in step (3) is as follows: the substrate loaded with metal oxide nanoparticles is placed in a metal salt solution of 0.05 to 50 mmol / L for 10 to 240 min to dope the metal element into the metal oxide nanoparticles; The doped metal element in step (3) is at least one of Ag, Ru, Au, Pd, Pt, Fe and Co; The electrochemical reduction in step (3) is carried out in a three-electrode system, wherein the constant potential is -3.0 to 0.4 V. RHE The restoration time is 10–3600 seconds. The specific method of reduction in step (3) is to dope the substrate loaded with metal oxide nanoparticles in step (2) with metal elements and then place it in a 0.001-3 mol / L reducing agent aqueous solution for immersion reduction for a reduction time of 10-3600 s.

2. The method for preparing an electrocatalyst for the anode of a biomass-derived aldehyde fuel cell according to claim 1, characterized in that, The electrolyte of the three-electrode system in step (3) is at least one of KOH, NaOH, Na2CO3, NaHCO3, K2CO3 and KHCO3, with a concentration of 0.05 to 5 mol / L; The reducing agent in step (3) is at least one of NaBH4, LiBH4 and Zn(BH4)2; The metal salt solution in step (3) is at least one of AgNO3, RuCl3, AuBr3, PdCl2, Pt(NO3)2, Fe(NO3)3 and Co(NO3)2.

3. The method for preparing an electrocatalyst for the anode of a biomass-derived aldehyde fuel cell according to claim 1, characterized in that, The cyclic voltammetry activation in step (2) is performed in a three-electrode system, with a scan range of -1.0 to 2.0 V. RHE The scanning speed is 0.5–100 mV / s, and the cycle is 1–100 revolutions. The electrolyte activated by the cyclic voltammetry method in step (2) is at least one of KOH, NaOH, Na2CO3, NaHCO3, K2CO3 and KHCO3, with a concentration of 0.05 to 5 mol / L; The electrochemical reduction in step (2) is carried out in a three-electrode system activated by cyclic voltammetry, wherein the constant potential is -3.0 to 0.4 V. RHE The restoration time is 10–3600 seconds. The reducing agent in step (2) is at least one of NaBH4, LiBH4 and Zn(BH4)2; specifically, the substrate of loaded nanoparticles activated by cyclic voltammetry is placed in a 0.001-3 mol / L aqueous solution of the reducing agent for impregnation and reduction, and the reduction time is 10-5000 s.

4. The method for preparing an electrocatalyst for the anode of a biomass-derived aldehyde fuel cell according to claim 1, characterized in that, The substrate in step (1) is at least one of copper foam, nickel foam, zinc foam, aluminum foam, carbon felt, carbon paper, and carbon cloth; The electrolyte used in the electrodeposition method in step (1) is at least one of CuSO4, CuCl2, Cu(NO3)2, AgNO3 and AuBr3, with a concentration of 0.01 to 3 mol / L; The electrolyte also contains 0.001–2 mol / L ethanol and 0.001–4 mol / L H2SO4; The electrodeposition process described in step (1) is carried out in a three-electrode system, wherein the constant current is -500 to -1 mA / cm. 2 The electrodeposition time is 10–5000 s.

5. An electrocatalyst prepared by the method according to any one of claims 1 to 4.

6. The application of the electrocatalyst according to claim 5 in a biomass-derived aldehyde fuel cell.

7. A biomass-derived aldehyde fuel cell that co-generates electricity and hydrogen, characterized in that, Includes anode, cathode, anolyte, catholyte, diaphragm, and wires; The anode is supported with the electrocatalyst described in claim 5; the anode electrolyte contains a biomass-derived aldehyde at a concentration of 1–1000 mmol / L.

8. The biomass-derived aldehyde fuel cell for co-producing electricity and hydrogen according to claim 7, characterized in that, The biomass-derived aldehyde in the anolyte is at least one of benzaldehyde, p-methoxybenzaldehyde, 3,4-dimethoxybenzaldehyde, furfural, 5-hydroxymethylfurfural, and formaldehyde; the concentration of the biomass-derived aldehyde in the anolyte is 1–1000 mmol / L. The alkali in the anolyte is at least one of NaOH, KOH and ammonia water, and the concentration of the alkali is 0.001 to 8 mol / L; The operating temperature of the biomass-derived aldehyde fuel cell is 5–98°C; The electrocatalyst is loaded as an anode catalyst in the anode channel inside the battery.

9. A biomass-derived aldehyde fuel cell for co-producing electricity and hydrogen according to claim 7, characterized in that, The cathode electrolyte comprises a ferric salt with a concentration of 0.01–4 mol / L, an acid solution with a concentration of 0.01–6 mol / L, and a cathode regeneration oxidant; The ferric salt is at least one of ferric chloride, ferric sulfate, and ferric nitrate; the acid solution is at least one of hydrochloric acid solution, sulfuric acid solution, and nitric acid solution; the cathode regeneration oxidant is at least one of nitric acid, oxygen, hydrogen peroxide, and potassium permanganate. When the cathode regeneration oxidant is nitric acid, its concentration in the cathode electrolyte is 0.01–8 mol / L; when the cathode regeneration oxidant is oxygen, its flow rate is 10–100 mL / min; when the cathode regeneration oxidant is hydrogen peroxide, its concentration is 0.2–10 mol / L; when the cathode regeneration oxidant is potassium permanganate, its concentration is 0.01–0.5 mol / L.

10. A biomass-derived aldehyde fuel cell for co-producing electricity and hydrogen according to claim 7, characterized in that, The anode and cathode are separated by a diaphragm to form an anode chamber containing an anode electrolyte and a cathode chamber containing a cathode electrolyte; The diaphragm is a Nafion membrane; The electrode material in the cathode is carbon felt; The biomass-derived aldehyde fuel cell also includes a circulation pump, which delivers the anode electrolyte and the cathode electrolyte to the anode and cathode, respectively. The wires connect the anode and cathode to the external circuit, respectively.

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