Electrocatalyst for biomass conversion and plastic degradation as well as preparation method and application of electrocatalyst

Abstract

The invention discloses an electrocatalyst for biomass conversion and plastic degradation as well as a preparation method and application of the electrocatalyst. According to the catalyst, a carbon-based material serves as a catalyst carrier, multi-component metal and multi-component metal oxide are loaded to prepare the catalyst of a binary metal interface structure, and the catalyst is recorded as NM / TMOx / C, NM is one or more of precious metal Au, Ag, Ir, In, Pd, Pt, Ru and Rh, TM is one or more of transition metal Co, Cu, Mn, Ni, Fe and Ti, the loading amount of NM is 0.5 wt%-35 wt%, and the loading amount of TM is 1 wt%-30 wt%; the invention also provides a preparation method and an application method of the catalyst. The catalyst NM / TMO / C is high in reaction rate of electrocatalytic oxidation of biomass and plastic degradation under low potential, high in selectivity of corresponding multi-electron products, good in CO toxicity resistance, good in stability and high in repeatability.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalysis for biomass conversion and plastic degradation, and particularly relates to an electrocatalyst for biomass conversion and plastic degradation, a preparation method thereof, and an application thereof. Background Art

[0002] Biomass is an important energy source. The selective catalytic oxidation of biomass-based aldols is one of the most important reactions in organic synthesis, with widespread applications in fine chemical production. The catalytic oxidation of aldols is a key pathway for converting carbohydrates into various organic acids and furanic chemicals. However, due to the complex reaction system and multiple reaction pathways, the catalytic mechanism remains unclear. For example, 5-hydroxymethylfurfural (HMF), an important biomass platform chemical with a wide range of natural sources, can be directly produced by dehydration of glucose or fructose. Because HMF possesses both alcoholic and aldehyde groups, it is considered an ideal model for studying the catalytic mechanism of liquid-phase selective oxidation of aldols (selective activation of carbon-oxygen single and double bonds). However, the current selective catalytic oxidation of biomass-based aldols is primarily carried out via thermal catalysis, which inevitably requires high temperature and pressure, precious metal catalysts, and some toxic oxidants, which is inconsistent with the principles of modern green synthesis. In contrast, electrocatalytic alcohol / aldehyde oxidation offers mild and controllable operating conditions (ambient temperature and pressure), continuous reaction capability, and low cost, making it a promising alternative for fine chemical production. The selective electrocatalytic oxidation of 5-hydroxymethylfurfural can replace the traditional anodic oxygen evolution reaction and reduce the cell pressure. At the same time, it can further selectively produce high-value-added products such as 2,5-furandicarboxaldehyde (DFF), 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), 5-formyl-2-furancarboxylic acid (FFCA), and 2,5-furandicarboxylic acid (FDCA), which is a "killing two birds with one stone" reaction. After reviewing a large number of literature and patents, it is known that there are many studies on the oxidation of HMF to FDCA at high potential (>1V), which are mainly designed around transition metal Co-based and Ni-based catalysts. The disadvantage is that the reaction to produce a 6-electron product (FDCA) usually requires a higher voltage than the 2-electron product (HMFCA) and the 4-electron product (FFCA). In this regard, people have adjusted and optimized nickel hydroxide by introducing precious metals such as Pt and Pd, but the voltage required for the reaction is still very high (>1.35V). For example, in the literature: Wang Shuangyin, et al., Hunan University. "Platinum regulates the redox properties of Ni(OH)2 and the adsorption kinetics of 5-hydroxymethylfurfural" German Journal of Applied Chemistry 2021 (60), nickel hydroxide-loaded Pt nanoparticle catalyst was designed and synthesized by hydrothermal and ethylene glycol high-temperature reduction methods. As a three-dimensional structure electrocatalyst with high FDCA selectivity at high potential (1.40 V), Pt itself cannot serve as an active species due to oxidation, but it improves the electrocatalytic activity of nickel hydroxide for HMF.The regulation of NiO by Ru has also been reported. For example, Duan Haohong, et al. from Tsinghua University, "Selective Electrooxidation of Biomass-Derived Alcohols to Aldehydes in Neutral Media: Promoting Water Dissociation on Ruthenium Single-Atom Catalysts Supported on Nickel Oxide", Angewandte Chemie International Edition 2022(61). A Ru1 / NiO catalyst was prepared by hydrothermally generating nickel hydroxide and then calcining it into nickel oxide, followed by impregnation and calcination. The Ru single atoms themselves do not act as active species but only provide *OH species, which promote the selective oxidation of HMF by the NiO catalyst under neutral conditions at a high potential (1.30V). In addition, the catalytic performance of some transition metal oxides has also attracted much attention. Chen Zupeng, et al. from Nanjing Forestry University, "Self-Reconstructed Surface Sulfate-Modified Copper Oxide Nanorods for Efficient and Stable Electrooxidation of 5-Hydroxymethylfurfural", Nano Letters 2023. A cuprous sulfide nanosheet (Cu2S NSs) model was prepared as a "pre-catalyst". A series of structural and compositional analyses confirmed that in electrochemical HMFOR, the S in Cu2S NSs... 2- Anions leach out in the form of SO4 2- and covalently bind to the surface of self-reconstructed copper oxide nanorods (CuO-SO4 2- NRs). CuO-SO4 2- NRs, as the "real catalyst", achieved complete conversion of 5-hydroxymethylfurfural in fifteen consecutive cycles, with the yield and Faraday efficiency of the target product 2,5-furandicarboxylic acid (FDCA) greater than 99.9%, and no deactivation. However, no catalyst that can achieve 100% FDCA selectivity at low potential has been reported yet.

[0003] In addition, plastics, especially PET plastics, are one of the main culprits causing "white pollution". Mineral water bottles, plastic cans, and the casings of some electrical appliances that we commonly use in daily life are basically made of PET plastics. Their main component is polyethylene terephthalate, and this polymer is difficult to degrade for hundreds of years under natural conditions. Currently, the global annual consumption of plastics reaches 245 million tons, and the current treatment methods for PET plastic waste include landfill, incineration, and recycling. Although landfill and incineration are simple to operate, the waste gases and wastewater generated will cause secondary pollution to the environment. Therefore, recycling is a more advocated treatment method. However, due to problems such as the high economic cost of plastic recycling and the low performance of recycled plastics, the current recycling rate is relatively low. The main current recycling method is to recycle through physical crushing, heating, and catalytic degradation. This not only requires the catalyst to react under high temperature and high pressure conditions, but also due to the difficulty in collecting products, it is impossible to achieve automated continuous degradation. In contrast, electrocatalytic plastic degradation has mild conditions, and the products can be regulated by controlling the potential. At the same time, it can achieve automated continuous production. The polyester structure of PET itself enables it to be easily hydrolyzed into terephthalic acid and ethylene glycol in an alkaline electrolyte. Ethylene glycol can undergo electrooxidation with high selectivity to form formate. This process is expected to be coupled with electrocatalytic oxidative cleavage to achieve the preparation of high-value chemicals from PET. Therefore, the research on electrocatalytic upgrading and recycling of waste PET plastics has broad prospects. For example, Hao-Hong Duan, et al. from Tsinghua University, "Electrocatalytic upgrading and recycling of polyethylene terephthalate to prepare chemical products and H2 fuel", Nature Communications 2021(12), used non-precious metal cobalt nickel phosphide as a bifunctional electrocatalyst to achieve the upgrading and recycling of waste polyethylene terephthalate (PET) plastics, electrocatalytically converting waste PET plastics into high-value terephthalic acid (PTA), potassium diformate (KDF), and H2 fuel. However, this technology requires a relatively high potential (~1.36V vs. RHE) to oxidize and dehydrogenate to form active intermediates Ni(OH)O and Co(OH)O, which determines that this electrocatalyst can only react at high potentials and cannot achieve electrocatalytic conversion at low potentials.

[0004] Deeply understanding the relationship between the catalyst structure and its selectivity for the activation of C-C, C-O bonds, and C=O bonds is a crucial step in achieving the general design of highly efficient catalysts for ultra-low potential biomass conversion and plastic degradation. Once high-selectivity six-electron product (FDCA) selectivity at low potential is achieved on noble metal-based materials, efficient HER can occur at ultra-low input voltage (<1V) and high-value organic products can be produced. More importantly, it provides a new solution for the rational design of low-cost, low-voltage, and stable electrolyzers to convert intermittent electrical energy generated from renewable energy.

[0005] Therefore, based on the above problems, it is of great practical significance to develop a catalyst and catalytic method for electrocatalytic selective oxidation of biomass conversion and plastic degradation, which has a high catalytic reaction rate, good stability, low cost, energy conservation and environmental protection. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies of the prior art and provide an electrocatalyst and catalytic method for electrocatalytic oxidation of biomass conversion and plastic degradation, which has a high catalytic oxidation reaction rate at low potential (<1.0V), high selectivity for corresponding multi-electron products, good CO anti-toxicity, good stability and strong reproducibility.

[0007] The present invention solves its technical problems by adopting the following technical solutions:

[0008] A catalyst for electrocatalytic selective oxidation of biomass conversion and plastic degradation, which uses a carbon-based material as a catalyst carrier and is loaded with multi-component metals and multi-component metal oxides to form a catalyst with a binary metal interface structure, denoted as: NM / TMO x / C, where NM is one or more of noble metals Au, Ag, Ir, In, Pd, Pt, Ru, Rh, and TM is one or more of transition metals Co, Cu, Mn, Ni, Fe, Ti. The loading amount of NM is 0.5wt%-35wt%, and the loading amount of TM is 1wt%-30wt%. The metal loading amount is obtained by measuring the content of transition metals or heavy metals in the catalyst by ICP-MS.

[0009] A preparation method of a catalyst for electrocatalytic selective oxidation of biomass conversion and plastic degradation, comprising the following steps:

[0010] (1) Take a transition metal salt solution, add ultrapure water, stir, and then add a catalyst carrier and stir;

[0011] (2) Add a reducing agent to the solution obtained in step (1) and carry out mechanical stirring reaction;

[0012] (3) After filtration, washing, centrifugation and drying, obtain a sample TM / C with transition metal loaded on the carrier;

[0013] (4) Take the TM / C sample obtained in step (3) and disperse it in one or two noble metal precursor solutions, stir continuously, and then obtain the catalyst NM / TM / C after filtration, washing, centrifugation and drying;

[0014] (5) Take the NM / TM / C obtained in step (4) and put it into a muffle furnace, calcine it in air, and cool it to room temperature after the calcination is completed to obtain NM / TMO x / C.

[0015] Further, the transition metal in step (1) is one or more of Co, Cu, Mn, Ni, and Fe.

[0016] Further, the catalyst support in step (1) is activated carbon, carbon black, graphene and its derivatives, carbon quantum dots, carbon nanofibers or carbon nanotubes.

[0017] Further, the reducing agent in step (2) is sodium borohydride solution, potassium borohydride solution, hydrazine hydrate or hydrogen peroxide.

[0018] Further, the noble metal precursor solution in step (4) contains 3+ Au + Ag 4+ Ir 3+ In 2+ Pd 4+ Pt 3+ Ru 3+ Rh

[0019] Further, in steps (3) and (4), the water used for washing needs to be deoxygenated by passing argon in advance.

[0020] Further, in step (5), the calcination temperature in the muffle furnace is 100 - 200 °C, and the calcination time is 2 - 3 h.

[0021] The catalyst for electrocatalytic oxidation of biomass conversion and plastic degradation prepared by the above method is applied to electrocatalytic biomass or plastics; in particular, this catalyst can be applied to the low - potential (<1 V) oxidation of organic substances such as benzyl alcohol, ethylene glycol, 5 - hydroxymethylfurfural, glycerol, and PET plastics.

[0022] Specifically, the method for electrocatalytic oxidation of biomass or plastics using the above catalyst is as follows:

[0023] First, hydrolyze 0.3 M PET plastics in 2 M KOH at 60 °C for 18 hours to obtain a PET hydrolysis product solution, and then prepare a 1 mol / L KOH + 1.0 mol / L PET plastic hydrolysis product solution (terephthalic acid and ethylene glycol monomers), and transfer it to a three - electrode system (H - type electrolytic cell, the cathode is 1 mol / L KOH solution). For biomass conversion, different substrates are used. For example, for the selective electro - oxidation of HMF to prepare FDCA, the electrolyte is 1 mol / L KOH + 50 mmol / L HMF, and carbon paper (1 cm 2)Using a working electrode, a platinum foil as the counter electrode, and a mercury / mercuric oxide electrode (Hg / HgO) as the reference electrode. 300 μL of the catalyst ink (5 mg / mL, 0.25% Nafion) was dropped onto the surface of the working electrode. Both biomass conversion and electrooxidation of plastics were carried out using an electrochemical workstation (BioLogic EC-Lab) at room temperature.

[0024] Compared with the existing technical solutions, the innovation of the technical solution of the present invention lies in:

[0025] In the present invention, metal oxides are prepared by a precipitation method and loaded on the surface of carbon black, and then an aqueous solution of a weakly acidic noble metal precursor (pH < 7) is added and stirred to etch the metal oxides. The etching of the metal oxides causes the pH value of the solution to increase, and the noble metal undergoes directional precipitation on the surface of the oxide, thereby preparing noble metal oxides loaded on the surface of ultrathin oxides. Then, the noble metal is electrochemically in-situ reduced by cyclic voltammetry to form a sufficient amount of noble metal / transition metal oxide NM / TMO x The interface effectively promotes the efficient electrocatalytic oxidation of biomass conversion and plastic degradation at room temperature. Different from the hydrothermal method with a reducing agent used in the existing technology to prepare noble metal / transition metal oxides, the method of first preparing metal oxides loaded on the surface of carbon black, then directional precipitation and in-situ electrochemical reduction in the present invention can achieve the precise loading of noble metals without adding a reducing agent at room temperature, and the finally obtained transition metal oxides are much smaller (ultrathin) than the transition metal oxide nanoparticles prepared by the traditional hydrothermal method. The loading of noble metals on ultrathin transition metal oxides is an important prerequisite for forming a sufficient amount of noble metal / transition metal hydroxide NM / TMO x interface, which cannot be achieved by traditional methods. Benefiting from this structure different from traditional catalysts, the NM / TMO x designed in the present invention, such as Pt / CuO x The catalyst performs an electrocatalytic reaction of HMF at a low voltage (0.6 V), achieving 100% selectivity for FDCA (the highest selectivity reported at present at low potentials), and continuously performing 5 electrochemical cycle reactions, with good catalyst stability and selectivity. By constructing the NM / TMO x binary metal interface structure, the electrocatalytic oxidation performance of the catalyst for biomass conversion and plastic degradation at low potentials (<1.0 V) is significantly improved.

[0026] The present invention has the following advantages and positive effects:

[0027] (1) The multi-metal interface structure nano-catalyst NM / TMO in the present invention xIt can efficiently electrocatalytically oxidize biomass conversion and plastic degradation at room temperature, improving the selectivity of multi-electron products. For example, this catalyst can achieve nearly 100% selective oxidation of HMF to FDCA at a low voltage (0.6V).

[0028] (2) By constructing the NM / TMO x / C binary metal interface structure, the electrocatalytic oxidation performance of the catalyst for biomass conversion and plastic degradation at low potentials (<1.0V) is significantly improved. For example, at a low potential of 0.75V, the oxidation current of HMF can reach more than 22.5mA, enabling a high-current and efficient electrocatalytic oxidation process for biomass conversion and plastic degradation. Description of the Drawings

[0029] Figure 1 High-resolution transmission electron microscopy image of the Pt / CuO x bimetallic catalyst of Example 1 of the present invention.

[0030] Figure 2 Reaction result of CV test for HMF oxidation at room temperature using cyclic voltammetry for the catalyst of Example 2 of the present invention.

[0031] Figure 3 Charge-time curve of HMF electrooxidation test at 0.75V vs. RHE using the potentiostatic method for the catalyst of Example 3 of the present invention.

[0032] Figure 4 Result of sampling and detecting the product distribution of the electrolyte after the HMF electrocatalytic oxidation reaction of the catalyst of Example 3 of the present invention at different voltages (0.3V, 0.4V, 0.5V, 0.6V, 0.75V, 0.9V).

[0033] Figure 5 Result of product distribution of the 12 consecutive cyclic stability tests of the catalyst of Example 3 of the present invention for HMF at a voltage of 0.75V vs. RHE.

[0034] Figure 6 Reaction result of LSV test for HMF oxidation at room temperature using cyclic voltammetry for the catalyst of Example 9 of the present invention.

[0035] Figure 7 Result of sampling and detecting the product distribution of the electrolyte after the HMF electrocatalytic oxidation reaction of the catalyst of Example 9 of the present invention at different voltages (0.6V, 0.8V, 1.0V).

[0036] Figure 8Product distribution results of the catalyst of Example 9 of the present invention for 10 consecutive cyclic stability tests of Pt / TiO2 at a voltage of 0.8 V vs. RHE. Detailed implementation manners

[0037] First of all, it should be noted that the following will specifically illustrate the specific structure, characteristics, advantages, etc. of the present invention by way of examples. However, all descriptions are only for illustration and should not be construed as forming any limitation to the present invention. In addition, any single technical feature described or implied in each embodiment mentioned herein can still be arbitrarily combined or deleted between these technical features (or their equivalents) to obtain more other embodiments of the present invention that may not be directly mentioned herein.

[0038] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary implementation manners according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0039] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0040] Example 1

[0041] Prepare CuO / C, Pt / CuO x 、Pt / CuO x - Etch the catalyst.

[0042] Preparation method of CuO / C: Weigh 0.054 g of CuCl·2H2O (purity 100%, theoretical 10 wt%) + 90 ml of ultrapure water and put them into a flask, ultrasonicate for 30 min and stir for 30 min. Add 0.18 g of carbon black, ultrasonicate for 30 min and stir for 2 h. Weigh 0.25 g of NaBH4 (37.83 g / mol) and dissolve it in 10 mL of ultrapure water, add it to the solution, and stir for 6 h after adding. Finally, filter and wash with water that has been deoxygenated by passing Ar in advance to obtain Cu / C;

[0043] Pt / CuO xPreparation method: Add Cu / C to 100 mL of ultrapure water (previously deoxygenated by purging with Ar). While stirring, add chloroplatinic acid hexahydrate dropwise (g / 10 mL, directly add 0.836 mL with a pipette gun), and then stir for 12 h. Filter by suction, dry overnight at 60 °C, label it, and record it as "Pt / Cu / C". Put PtCu / C into a muffle furnace, calcine it in air at 150 °C for 2 h, and the heating rate is 5 °C·min -1 After the calcination is completed, cool it to room temperature to obtain Pt / CuO x catalyst.

[0044] Pt / CuO x -etching preparation method: Dilute 20 mg of Pt / CuO x catalyst in 30 mL of aqueous solution, and etch it with 2 M dilute nitric acid (2.66 mL) for 12 h, then filter by suction and dry.

[0045] Figure 1 is the transmission electron microscopy image of the Pt / CuOx bimetallic catalyst.

[0046] Example 2

[0047] Perform an electrocatalytic oxidation of HMF experiment using the catalyst prepared in Application Example 1 and commercial Pt / C.

[0048] Pt / CuO x as the catalyst: Prepare 1 mol / L KOH solution as the cathode electrolyte (20 mL), 1 mol / L KOH + 50 mmol / L HMF solution as the anode electrolyte (20 mL), and transfer it to a three-electrode system (H-type electrolytic cell). Use carbon paper (1 cm 2 ) as the working electrode, platinum foil as the counter electrode, and mercury / mercuric oxide electrode (Hg / HgO) as the reference electrode. Take 300 μL of catalyst ink (5 mg / mL, 0.25% Nafion) and drop it onto the surface of the working electrode. Both biomass conversion and electrooxidation of plastics are carried out using an electrochemical workstation (BioLogic EC-Lab) at room temperature. The reaction results are as Figure 2 shown.

[0049] Pt / CuO x -etching as the catalyst: The operating procedure is the same as that of Pt / CuO x as the catalyst. Replace Pt / CuO x with Pt / CuO x -etching, and the reaction results are as Figure 2 shown.

[0050] CuO / C as the catalyst: The operating procedure is the same as that of Pt / CuO xAs a step of the catalyst, replace Pt / CuO x with CuO / C, and the reaction results are as shown in the appendix Figure 2 .

[0051] Commercial Pt / C as the catalyst: The operation steps are the same as those of the above Pt / CuO x As a step of the catalyst, replace Pt / CuO x with commercial Pt / C, the sweep rate is 5 mV / s, and the reaction results are as shown in Figure 2 .

[0052] It can be seen from Figure 2 that for the electrocatalytic oxidation reaction of HMF, CuO / C does not show reaction activity, while the peak current density of the Pt / CuO x bimetallic catalyst reaches 22.5 mA / cm 2 , which is 6.4 times that of the commercial Pt / C catalyst (3.5 mA / cm 2 ). More importantly, the catalytic performance of the monometallic catalyst (Pt / CuO x -etched) after etching off CuO is significantly reduced, and the peak current density drops to 9.8 mA / cm 2 , because the Cu-O-Pt interface is very crucial for the electrocatalytic oxidation reaction of HMF, indicating that the noble metal / transition metal hydroxide NM / TMO x interface effectively promotes the efficient electrocatalytic oxidation of biomass conversion and plastic degradation at room temperature.

[0053] Example 3

[0054] Pt / CuO x 、Pt / CuO x -etched, and constant voltage product testing of commercial Pt / C catalyst.

[0055] The reaction conditions are as follows: Prepare 1 mol / L KOH solution as the cathode electrolyte (20 mL), 1 mol / L KOH + 5 mmol / L HMF solution as the anode electrolyte (10 mL), and transfer them to a three-electrode system (H-type electrolytic cell). Use carbon paper (1 cm 2 ) as the working electrode, platinum foil as the counter electrode, and mercury / mercuric oxide electrode (Hg / HgO) as the reference electrode. Drop 300 μL of catalyst ink (5 mg / mL, 0.25% Nafion) onto the surface of the working electrode. Use an electrochemical workstation (BioLogic EC-Lab) to perform tests at a constant voltage of 0.75 V (vs. RHE) at room temperature. The reaction results are as shown in Figure 3 .

[0056] Example 4

[0057] The electrolyte after the electrocatalytic oxidation reaction of HMF with the catalyst in Application Example 3 at different voltages (0.5 V, 0.6 V, 0.75 V, 0.9 V) was sampled and tested for product distribution.

[0058] The product detection conditions were as follows:

[0059] The reaction was carried out at different voltages (0.5 V, 0.6 V, 0.75 V, 0.9 V), and 50 μL was sampled at different coulomb amounts (0 C, 9.65 C, 19.3 C, 29.95 C), and diluted to 1 mL with 950 μL of 5 mM ammonium formate aqueous solution (70%) + methanol (30%). High-performance liquid chromatography was used to quantitatively detect the products. After the column pressure was stable, detection was carried out with a full-wavelength ultraviolet detector in a diode array. The wavelength (265 nm) with the strongest product response and the highest resolution was selected for spectral collection and quantification. The injection volume each time was 10 μL, and the product data was converted with a standard sample and statistically analyzed.

[0060] Pt / CuO x 、Pt / CuO x -etching, the product test results of commercial Pt / C catalyst at different voltages are as Figure 4 。

[0061] From Figure 4 it can be seen that the products of each catalyst in the reaction at different voltages (0.5 V, 0.6 V, 0.75 V, 0.9 V) are quite different. Among them, the selectivity of Pt / CuO x to FDCA is close to 100% at 0.75 V, which is significantly improved compared with the etched Pt / CuO x -etching (66.3% FDCA selectivity) and commercial Pt / C (37.1% FDCA selectivity) catalysts. By comparing with the literature, the Pt / CuO x bimetallic catalyst shows the highest FDCA product selectivity not reported at low potentials (<1.0 V).

[0062] Example 5

[0063] The cyclic stability test and product detection of Pt / CuO x were carried out

[0064] The stability test and product detection conditions were as follows: Prepare 1 mol / L KOH solution as the cathode electrolyte (20 mL), 1 mol / L KOH + 5 mmol / L HMF solution as the anode electrolyte (10 mL), and transfer it to a two-electrode system (flow-through electrolytic cell). Use carbon paper (4 cm x sprayed with Pt / CuO 2A carbon paper sprayed with commercial Pt / C catalyst was used as the anode, and a carbon paper sprayed with commercial Pt / C catalyst was used as the cathode. 3 mL of catalyst ink (10 mg / mL, 0.25% Nafion) was dropped onto the surface of the working electrode. A chronoamperometry test was carried out at 0.75 V (vs. RHE) at room temperature using an electrochemical workstation (BioLogic EC-Lab). The reaction solution was pumped through the electrode surface for reaction. 50 μL of the reacted liquid was sampled and collected at regular intervals, diluted to 1 mL with 950 μL of 5 mM ammonium formate aqueous solution (70%) + methanol (30%), and the product was quantitatively detected by high performance liquid chromatography. After the column pressure was stabilized, detection was carried out with a full wavelength UV detector of a diode array, and the wavelength with the strongest product response and the highest resolution (265 nm) was selected for spectral collection and quantification. The injection volume for each injection was 10 μL. The product data of multiple long-term reactions were recorded and subjected to standard sample conversion and statistics.

[0065] It can be seen from Figure 5 that the products of the Pt / CuO x catalyst in the catalytic oxidation reaction at a voltage of 0.75 V have little difference, and the selectivity for FDCA is very high, approaching 100%, indicating that the Pt / CuO x catalyst has good stability and strong repeatability.

[0066] Example 6

[0067] Preparation of Pd / CuO x catalyst:

[0068] Preparation method of CuO / C: Weigh 0.054 g of CuCl·2H2O (purity 100%, theoretical 10 wt%) + 90 ml of ultrapure water and put them into a conical flask, ultrasonic for 30 min and stir for 30 min. Add 0.18 g of carbon black, ultrasonic for 30 min and stir for 2 h. Weigh 0.25 g of NaBH4 37.83 g / mol and dissolve it in 10 mL of ultrapure water, add it to the solution, and stir for 6 h after adding. Finally, filter and wash with water that has been deoxygenated by passing Ar in advance to obtain Cu / C.

[0069] Pd / CuO x Preparation method:

[0070] Pd / CuO x -etching preparation method: Pipette 0.035 g of the above Pd / CuO x solution into a beaker, add 30 mL of 0.5 mol / L dilute nitric acid solution, mechanically stir at room temperature for 2.0 hours to remove CuO, filter and wash, wash several times with ethanol and deionized water, put it in a vacuum drying oven at 60 °C and dry for 24 hours, grind, weigh, and obtain the etched Pt / CuO x -etching.

[0071] Example 7

[0072] An experiment on the electrocatalytic oxidation degradation reaction of plastics was carried out using the catalyst prepared in Application Example 6.

[0073] First, 0.3M PET plastic was hydrolyzed in 2M KOH at 60 °C for 18 hours to obtain a PET hydrolyzate solution, which was then formulated into a 1mol / L KOH + 1.0mol / L PET hydrolyzate solution (terephthalic acid and ethylene glycol monomers), and transferred to a three-electrode system (H-type electrolytic cell, the cathode is 1mol / L KOH solution). The electrolyte was 1mol / L KOH + 50mmol / L HMF. Carbon paper (1cm 2 ) was used as the working electrode, platinum foil as the counter electrode, and mercury / mercuric oxide electrode (Hg / HgO) as the reference electrode. 300 μL of catalyst ink (5mg / mL, 0.25% Nafion) was dropped onto the surface of the working electrode. The electrooxidation of biomass was carried out using an electrochemical workstation (BioLogic EC-Lab) at room temperature.

[0074] Example 8

[0075] The solution after the electrocatalytic oxidation degradation reaction of plastics in Example 7 was sampled for product detection.

[0076] The product was detected by nuclear magnetic resonance. It was found that ethylene glycol in the PET hydrolysis solution underwent an oxidation reaction at the anode, selectively breaking the C-C bond and generating formate. Formic acid was further added to the electrolyte, and high-purity and high-value-added terephthalic acid could be obtained by filtration. The filtrate was further concentrated and crystallized to obtain high-value-added potassium diformate (KDF), and the product purity was determined by X-ray powder diffraction and single crystal diffraction. It was found that there were differences in the results of the electrocatalytic oxidation degradation reaction of plastics tested with different catalysts. Compared with the etched Pd / CuO x , CuO / C and commercial Pd / C (20% Pt content) catalysts, the Pd / CuO x bimetallic catalyst showed the highest reaction activity.

[0077] It should be noted that in the above examples, the room temperature mentioned in the present invention refers to a temperature of 15 - 25 °C; in addition, the noble metal atomic ratio in the catalyst was tested and calculated by ICP-OES.

[0078] Example 9

[0079] Synthesis method of Pt / TiO2: Weigh 28mg of C 10 H 14 O4Pt and 1.62mg of TiO2 (P25), and mix C 10 H 14O4Pt was mixed with TiO2 and further mixed with 14 mL of benzyl alcohol (C6H5CH2OH) in a pressure-resistant flask. After stirring at room temperature for 5 minutes, it was heated to 180 °C in an oil bath and vigorously stirred for 3 hours. During the oil bath heating, CO was continuously introduced into the pressure-resistant flask. After the heating was completed, it was cooled to room temperature. The reaction solution was centrifuged to obtain a black solid, which was washed, centrifuged, and dried multiple times to obtain Pt / TiO2.

[0080] Synthesis method of Pt / C: Weigh 28 mg of C 10 H 14 O4Pt and 1.62 mg of carbon black. Mix C 10 H 14 O4Pt with carbon black and further mix with 14 mL of benzyl alcohol (C6H5CH2OH) in a pressure-resistant flask. After stirring at room temperature for 5 minutes, it was heated to 180 °C in an oil bath and vigorously stirred for 3 hours. During the oil bath, CO was continuously introduced into the pressure-resistant flask. After the heating was completed, it was cooled to room temperature. The reaction solution was centrifuged to obtain a black solid, which was centrifuged, washed, and dried multiple times to obtain Pt / C.

[0081] Example 10

[0082] The electrocatalytic oxidation of HMF was carried out using the catalyst prepared in Application Example 9 and commercial TiO2 (P25).

[0083] Using Pt / TiO2 as the catalyst: Prepare 1 mol / L KOH solution as the cathode electrolyte (20 mL), 1 mol / L KOH + 50 mmol / L HMF solution as the anode electrolyte (20 mL), and transfer them to a three-electrode system. Use carbon paper (0.5 cm 2 ) as the working electrode, platinum foil as the counter electrode, and mercury / mercuric oxide electrode (Hg / HgO) as the reference electrode. Take 500 μL of catalyst ink (4 mg / mL, 0.5% Nafion) and drop it onto the surface of the working electrode. Both biomass conversion and electrooxidation of plastics were carried out using an electrochemical workstation (BioLogic EC-Lab) at room temperature. The reaction results are as Figure 6 shown.

[0084] Using Pt / C as the catalyst: The operation steps are the same as those when using Pt / TiO2 as the catalyst. Replace Pt / TiO2 with Pt / C. The reaction results are as Figure 6 shown.

[0085] Using TiO2 as the catalyst: The operation steps are the same as those when using Pt / TiO2 as the catalyst. Replace Pt / TiO2 with TiO2. The reaction results are as Figure 6 shown.

[0086] From Figure 6It can be seen that for the electrocatalytic oxidation reaction of HMF, TiO2 did not show reaction activity, while the peak current density of the Pt / TiO2 bimetallic catalyst reached 34 mA / cm 2 , which is 1.6 times that of the Pt / C catalyst (22 mA / cm 2 ), indicating that the noble metal / transition metal oxide NM / TMO x interface effectively promoted the efficient electrocatalytic oxidation of biomass conversion and plastic degradation at room temperature.

[0087] Example 11

[0088] Samples of the electrolyte after the electrocatalytic oxidation reaction of HMF were taken and tested for product distribution using the catalyst in Example 10 at different voltages (0.6 V, 0.8 V, 1.0 V).

[0089] The product detection conditions were as follows: 1 mol / L KOH solution was prepared as the cathode electrolyte (15 mL), and 1 mol / L KOH + 6 mmol / L HMF solution was used as the anode electrolyte (15 mL). The reaction was carried out at different voltages (0.6 V, 0.8 V, 1.0 V), and 75 μL samples were taken at different coulomb amounts (0 C, 17.4 C, 19.3 C, 29.95 C) and diluted to 1.5 mL with 1.425 mL of 5 mM ammonium formate aqueous solution (70%) + methanol (30%). High-performance liquid chromatography was used to quantitatively detect the products. After the column pressure was stabilized, detection was carried out with a full-wavelength ultraviolet detector in a diode array. The wavelength with the strongest product response and the highest resolution (265 nm) was selected for spectral collection and quantification. The injection volume for each sample was 10 μL, and the product data was converted and statistically analyzed using a standard sample.

[0090] The test results of the products of Pt / TiO2 and Pt / C catalysts at different voltages are as Figure 7 .

[0091] As can be seen from Figure 7 , the products of each catalyst showed significant differences when reacting at different voltages (0.6 V, 0.8 V, 1.0 V). Among them, the selectivity of Pt / TiO2 for FDCA was close to 100% at 0.8 V, showing a significant improvement compared to Pt / C (62.7% FDCA selectivity).

[0092] Example 12

[0093] The cyclic stability test and product detection of Pt / TiO2 were carried out.

[0094] The conditions for stability testing and product detection are as follows: Prepare 1 mol / L KOH solution as the cathode electrolyte (15 mL), 1 mol / L KOH + 6 mmol / L HMF solution as the anode electrolyte (15 mL), and transfer them to a three-electrode system (H-type electrolytic cell). Use carbon paper (2 cm 2 ) as the working electrode, platinum foil as the counter electrode, and mercury / mercuric oxide electrode (Hg / HgO) as the reference electrode. Drop 2 mL of catalyst ink (10 mg / mL, 0.5% Nafion) onto the surface of the working electrode. Use an electrochemical workstation (BioLogic EC-Lab) to perform 10 chronoamperometry tests at 0.8 V (vs. RHE) at room temperature and collect 75 μL samples at different coulomb amounts (0 C, 17.4 C, 19.3 C, 29.95 C), and dilute them to 1.5 mL with 1.425 mL of 5 mM ammonium formate aqueous solution (70%) + methanol (30%). Use high-performance liquid chromatography to quantitatively detect the products. Wait until the column pressure is stable, and detect them with a full-wavelength ultraviolet detector in a diode array. Select the wavelength (265 nm) with the strongest product response and the highest resolution for spectral collection and quantification. The injection volume for each injection is 10 μL, and perform standard sample conversion and statistics on the product data.

[0095] As can be seen from Figure 8 , the differences in the products of the Pt / TiO2 catalyst during 10 consecutive cyclic reactions at a voltage of 0.8 V are small, and the selectivity for FDCA is very high, close to 100%, indicating that the Pt / TiO2 catalyst has good stability and strong repeatability.

[0096] In summary, the present invention overcomes the deficiencies of the prior art and provides a method for constructing a NM / TMO x / C binary metal interface structure, which has a fast reaction rate for electrocatalytic oxidation of biomass conversion and plastic degradation at low potentials (<1.0 V), high selectivity for corresponding multi-electron products, good stability, and strong repeatability.

[0097] The above embodiments have described the present invention in detail, but the content described is only the preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. An electrocatalyst for biomass conversion and plastic degradation, which is mainly characterized in that the catalyst uses a carbon-based material as a catalyst carrier and is made into a supported catalyst NM / TMO x / C with a binary metal interface structure by loading multi-component metals and multi-component metal oxides; where NM is one or more of precious metals Au, Ag, Ir, In, Pd, Pt, Ru, Rh, and TM is one or more of transition metals Co, Cu, Mn, Ni, Fe, Ti, and the loading amount of NM is 0.5 wt% - 35 wt%, and the loading amount of TM is 1 wt% - 30 wt%.

2. The preparation method of an electrocatalyst for biomass conversion and plastic degradation according to claim 1, characterized in that, It includes the following steps: (1) Take a transition metal salt and add ultrapure water, stir, and then add a catalyst support and stir; (2) Add a reducing agent to the solution obtained in step (1), and carry out a mechanical stirring reaction; (3) Obtain a sample TM / C with the transition metal loaded on the support through filtration, washing, centrifugation and drying; (4) Take the sample TM / C obtained in step (3) and disperse it in a noble metal precursor solution, and keep stirring, and then obtain a catalyst NM / TM / C through filtration, washing, centrifugation and drying; (5) Load the NM / TM / C obtained in step (4) into a muffle furnace, calcine it in air, and cool it to room temperature after the calcination is completed to obtain NM / TMO x / C.

3. The preparation method of an electrocatalyst for biomass conversion and plastic degradation according to claim 2, characterized in that, In step (1), the transition metal in the transition metal salt is one or more of Co, Cu, Mn, Ni, and Fe.

4. The preparation method of an electrocatalyst for biomass conversion and plastic degradation according to claim 2, characterized in that, In step (1), the catalyst support is activated carbon, carbon black, graphene and its derivatives, carbon quantum dots, carbon nanofibers or carbon nanotubes.

5. The preparation method of an electrocatalyst for biomass conversion and plastic degradation according to claim 2, wherein, In step (2), the reducing agent is a sodium borohydride solution, a potassium borohydride solution, hydrazine hydrate or hydrogen peroxide.

6. The preparation method of an electrocatalyst for biomass conversion and plastic degradation according to claim 2, characterized in that, In step (4), the noble metal precursor solution is an aqueous solution containing one or more of 3+ Au + Ag 4+ Ir 3+ In 2+ Pd 4+ Pt 3+ Ru 3+ Rh 7. The preparation method of an electrocatalyst for biomass conversion and plastic degradation according to claim 2, characterized in that, In steps (3) and (4), the water used for washing needs to be deoxygenated by passing argon in advance.

8. The preparation method of an electrocatalyst for biomass conversion and plastic degradation according to claim 2, characterized in that, In step (5), the calcination temperature in the muffle furnace is 100-200 °C, and the calcination is carried out for 2-3 h.

9. The electrocatalyst described in claim 1 is used for electrocatalytic selective oxidation of biomass conversion and plastic degradation.

10. Use of the catalyst according to claim 9, characterized in that, It is used for electrocatalytic low-potential oxidation of benzyl alcohol, ethylene glycol, 5-hydroxymethylfurfural, amino acids, glucose, starch, cellulose, glycerol, and PET plastics with an organic matter of less than 1.0 V.

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