Electrocatalyst for biomass upgrading and plastic degradation and preparation method and application thereof

Abstract

The application discloses an electrocatalyst for biomass upgrading and plastic degradation, and a preparation method and application thereof. The catalyst takes a carbon-based material as a catalyst carrier, loads multiple-component metals and multiple-component metal hydroxides to form a catalyst with a binary metal interface structure, and is denoted as NM / TM(OH)2 / C, wherein NM is one or more of noble metals Pt, Pd, Ru, Au, Rh, Ir or Ag, TM is one or more of transition metals Ni, Co, Cu or Fe, the loading amount of NM is 0.5wt%-35wt%, and the loading amount of TM is 1wt%-30wt%. The application further provides a preparation method and an application method of the catalyst. The catalyst NM / TM(OH)2 / C has high electrocatalytic biomass and plastic degradation oxidation reaction rate at a low potential (<1.0V), high selectivity of corresponding multi-electron products, good CO resistance, good stability and strong repeatability.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology for biomass upgrading and plastic degradation, and particularly relates to an electrocatalyst for biomass upgrading and plastic degradation, its preparation method and application. Background Technology

[0002] Biomass is an important energy source, and the selective catalytic oxidation of biomass-based alcohols and aldehydes is one of the most important reactions in organic synthesis, with wide applications in fine chemical production. The catalytic oxidation of alcohols and aldehydes is a key pathway for converting carbohydrates into various organic acids and furans, but due to the complexity of the reaction system and multiple reaction pathways, its catalytic mechanism is not yet fully understood. For example, 5-hydroxymethylfurfural (HMF), as an important biomass platform chemical, is widely available and can be directly generated from the dehydration of glucose or fructose. Because it possesses both alcoholic and aldehyde groups, it is considered an ideal model for studying the liquid-phase selective oxidation catalytic mechanism of alcohols and aldehydes (selective activation of carbon-oxygen single and double bonds). However, current biomass-based selective catalytic oxidation of alcohols and aldehydes (such as 5-hydroxymethylfurfural) mainly employs thermocatalysis, which inevitably requires high temperature and pressure, precious metal catalysts, and some toxic oxidants, which does not conform to 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 method for fine chemical production. The selective electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) not only replaces the traditional anodic oxygen evolution reaction (OER) to reduce cell voltage, but also selectively generates high-value-added products such as 5-hydroxymethyl-2-furanic acid (HMFCA), 2,5-furandicarboxaldehyde (DFF), 5-formyl-2-furanic acid (FFCA), and 2,5-furandicarboxylic acid (FDCA), making it a "two birds with one stone" reaction. A review of numerous literature and patents reveals that there is considerable research on the high-potential oxidation of HMF to FDCA (>1V), primarily focusing on transition metal Co-based and Ni-based catalysts. Unfortunately, HMF electrooxidation on typical nickel-based electrocatalysts such as β-Ni(OH)₂ typically requires relatively high potentials (~1.36V vs. RHE) to oxidize and dehydrogenate to form the active intermediate Ni(OH)O. Furthermore, the reaction generating the 6-electron product (FDCA) usually requires even higher voltages than the 2-electron product (HMFCA) and the 4-electron product (FFCA). In this regard, people have adjusted and optimized nickel hydroxide by introducing noble metals such as Pt, 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-modulated redox properties of Ni(OH)2 and adsorption kinetics of 5-hydroxymethylfurfural", Angewandte Chemie 2021 (60), a nickel hydroxide-supported Pt nanoparticle catalyst was designed and synthesized by hydrothermal and high-temperature reduction with ethylene glycol. As a three-dimensional electrocatalyst with high FDCA selectivity at high potential (1.40V), Pt itself cannot be used as an active species because it is oxidized, but it improves the electrocatalytic activity of nickel hydroxide for HMF.Ru's regulation of NiO has also been reported, such as in Tsinghua University, Duan Haohong, et al., "Selective Electrooxidation of Biomass-Derived Alcohols to Aldehydes in Neutral Media: Promoting Water Dissociation on a Ruthenium Single-Atom Catalyst Supported in Nickel Oxide", Angewandte Chemie 2022(61). This study describes the preparation of a Ru1 / NiO catalyst by hydrothermal generation of nickel hydroxide followed by calcination to nickel oxide, and then impregnation and calcination. The Ru single atom itself does not act as an active species but only provides the *OH species, promoting the selective oxidation of HMF by the NiO catalyst under neutral conditions at a high potential (1.30V). However, catalysts achieving 100% FDCA selectivity at low potentials have not yet been reported.

[0003] Furthermore, plastics, especially PET plastics, are a significant source of "white pollution." Commonly used mineral water bottles and plastic cans are primarily made of PET plastic, whose main component is polyethylene terephthalate (PET). This polymer is difficult to degrade under natural conditions for hundreds of years. Currently, the world consumes and generates 245 million tons of plastic annually. Current methods for treating PET plastic waste include landfill, incineration, and recycling. While landfill and incineration are simple, the resulting waste gas and wastewater cause secondary pollution. Recycling is currently the more advocated method, but due to the economic costs of recycling and the performance issues of recycled plastics, the current recycling rate is low. Currently, recycling is mainly achieved through physical crushing, heating, and catalytic degradation. This requires catalysts to react under high temperature and high pressure conditions, and product collection is difficult, making automated continuous degradation impossible. In contrast, electrocatalytic plastic degradation offers milder conditions, and the products can be controlled by adjusting the potential, enabling automated continuous production. This is an emerging technology in recent years. The polyester structure of PET allows it to be easily hydrolyzed in alkaline electrolytes into terephthalic acid and ethylene glycol. For example, ethylene glycol can undergo highly selective electro-oxidation to generate formate. This process holds promise for coupling with electrocatalytic oxidative cracking to produce high-value chemicals from PET. Therefore, research on the electrocatalytic upgrading and recycling of waste PET plastics has broad prospects. For example, Tsinghua University, Duan Haohong, et al. "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 upgrade and recycle waste polyethylene terephthalate (PET) plastics. The electrocatalytic conversion of waste PET plastics into high-value-added 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 the electrocatalyst can only react at high potentials and cannot achieve electrocatalytic conversion at low potentials.

[0004] A deep understanding of catalyst structure and its relationship to the selectivity of C=C, CO, and C=O bond activation is a crucial step towards the universal design of highly efficient catalysts for ultra-low potential biomass upgrading and plastic degradation. Once high selectivity for six-electron products (FDCA) at low potentials is achieved on noble metal-based materials, the production of highly efficient HER and high-value-added organic products with ultra-low input voltages (<1V) will be realized. More importantly, it provides a new solution for the rational design of low-cost, low-voltage, and stable electrolyzers to convert intermittent electricity generated from renewable energy sources.

[0005] Therefore, based on the above problems, developing a catalyst and catalytic method for the electrocatalytic selective oxidation of biomass upgrading and plastic degradation with high reaction rate, good stability, low cost, energy saving and environmental protection is of great practical significance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an electrocatalyst and catalytic method for the electrocatalytic oxidation of biomass upgrading and plastic degradation that has a high catalytic oxidation reaction rate at low potential (<1.0V), high selectivity of corresponding multi-electron products, good CO antitoxicity, good stability, and strong reproducibility.

[0007] The technical problem solved by this invention is achieved through the following technical solution:

[0008] A catalyst for the selective electrocatalytic oxidation of biomass upgrading and plastic degradation is disclosed. Using a carbon-based material as the catalyst support, a multi-component metal and multi-component metal hydroxide are loaded to form a supported catalyst with a binary metal interface structure, denoted as NM / TM(OH)2 / C. NM is one or more noble metals such as Pt, Pd, Ru, Au, Rh, Ir, or Ag, and TM is one or more transition metals such as Ni, Co, Cu, or Fe. The loading of NM is 0.5 wt%–35 wt%, and the loading of TM is 1 wt%–30 wt%. The metal loading is obtained by measuring the content of transition metals or heavy metals in the catalyst using ICP-MS.

[0009] The preparation method of the catalyst for the electrocatalytic selective oxidation of biomass upgrading and plastic degradation includes the following steps:

[0010] (1) Take a transition metal salt solution and add a coordination solvent, stir, and then add a catalyst support and stir.

[0011] (2) Add an alkaline solution to the solution obtained in step (1) to adjust the pH of the solution to 8-14; and carry out mechanical stirring reaction at 5-35℃ for 0.5-48h;

[0012] (3) After filtration, washing, centrifugation and drying, a sample TM(OH)2 / C with transition metal loaded on a carrier was obtained;

[0013] (4) Disperse the TM(OH)2 / C sample obtained in step (3) in one or two noble metal precursor solutions and stir continuously. Allow the precipitation reaction to proceed at room temperature for 0.5-24 hours. Then, filter, wash, centrifuge, and dry to obtain the catalyst NM-O. x / TM(OH)2 / C.

[0014] (5) Take the NM-O obtained in step (4) x / TM(OH)2 / C was reduced to NM / TM(OH)2 / C through in-situ electrochemical reduction.

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

[0016] Furthermore, the coordination solvent in step (1) is ethanol, ethylene glycol, aniline, or ethylenediamine.

[0017] Furthermore, the catalyst support described in step (1) is carbon black, activated carbon, graphene and its derivatives, carbon quantum dots or carbon nanotubes.

[0018] Furthermore, in step (1), the volume ratio of the transition metal salt solution to the coordination solvent is 9:1.

[0019] Furthermore, the alkaline solution mentioned in step (2) is NaOH solution, sodium bicarbonate solution, sodium carbonate solution, hydrazine hydrate or NH3·H2O.

[0020] Furthermore, the noble metal precursor solution mentioned in step (4) is Pt-containing 4+ Pd 2+ Ru 3+ Au 3+ ,Rh 3+ Ir 4+ or Ag + One or more of the following in aqueous solution.

[0021] Furthermore, in step (5), the in-situ electrochemical reduction is carried out by cyclic voltammetry or potentiostatic method in the reduction potential range of the noble metal (for example, the reduction potential range of Pd is 0-0.6V vs. RHE).

[0022] The catalyst prepared by the above method for the electrocatalytic oxidation of biomass upgrading and plastic degradation can be applied to the electrocatalytic oxidation of biomass or plastics; in particular, the catalyst can be applied to the low-potential (<1.0V) oxidation of 5-hydroxyfurfural, benzyl alcohol, ethylene glycol, glucose, glycerol, and PET.

[0023] Specifically, the method for electrocatalytic oxidation of biomass or plastics using the above-mentioned catalyst is as follows:

[0024] First, 0.3M PET plastic is hydrolyzed in 2M KOH at 60℃ for 18 hours to obtain a PET hydrolysate solution. This solution is then prepared as a 1mol / L KOH + 1.0mol / L PET plastic hydrolysate solution (terephthalic acid and ethylene glycol monomers), and transferred to a three-electrode system (H-type electrolytic cell, both cathodes are 1mol / L KOH solution). For biomass upgrading, different substrates are used; for example, in the selective electrooxidation of HMF to prepare FDCA, the electrolyte is 1mol / L KOH + 50mmol / L HMF, using carbon paper (1cm). 2 A platinum foil electrode was used as the working electrode, a mercury / mercury oxide electrode (Hg / HgO) as the reference electrode, and 300 μL of catalyst ink (5 mg / mL, 0.25% Nafion) was dropped onto the surface of the working electrode. Both biomass upgrading and plastic electrooxidation were performed at room temperature using an electrochemical workstation (BioLogic EC-Lab).

[0025] The innovation of the present invention compared with the existing technical solutions lies in:

[0026] This invention prepares metal hydroxides loaded onto carbon black surfaces via a precipitation method. A weakly acidic noble metal precursor (pH < 7) is then added to the solution, and the mixture is stirred to etch the metal hydroxides. The etching process causes the pH of the solution to rise, leading to the directional precipitation of the noble metal onto the hydroxide surface. This process produces noble metal oxides loaded onto an ultrathin hydroxide surface. The noble metal is then reduced in situ via cyclic voltammetry to form a sufficient quantity of noble metal / transition metal hydroxides (NM / TM(OH)). x The interface effectively promotes efficient electrocatalytic oxidation of biomass upgrading and plastic degradation at room temperature. Unlike existing technologies that use hydrothermal methods with reducing agents to prepare noble metal / transition metal hydroxides, this invention first prepares the metal hydroxide, loads it onto the carbon black surface, then directionally precipitates and performs in-situ electrochemical reduction. This method achieves precise loading of noble metals at room temperature without the need for a reducing agent. Furthermore, the resulting transition metal hydroxide nanoparticles are much smaller (ultra-thin) than those prepared by traditional hydrothermal methods. Loading noble metals onto ultra-thin transition metal hydroxides allows for the formation of a sufficient number of noble metal / transition metal hydroxide NM / TM(OH) particles. x This is a crucial prerequisite for interface design, which traditional methods cannot achieve. Thanks to its unique structure compared to traditional catalysts, the NM / TM(OH) designed in this invention... xFor example, the Pd / Ni(OH)₂ / C catalyst achieved 100% selectivity for FDCA in the HMF electrocatalytic reaction at a low voltage (0.6V), which is the highest selectivity reported to date at low potentials. Furthermore, it underwent five consecutive electrochemical cycles, demonstrating good catalyst stability and selectivity. This invention, by constructing a NM / TM(OH)₂ / C binary metal interface structure, significantly improves the electrocatalytic oxidation performance of the catalyst for biomass upgrading and plastic degradation at low potentials (<1.0V).

[0027] This invention has the following advantages and positive effects:

[0028] (1) The multi-metal interface structure nanocatalyst NM / TM(OH)2 / C in this invention can efficiently electrocatalyze the oxidation of biomass upgrading and plastic degradation at room temperature, and improve the selectivity of multi-electron products. For example, this catalyst can achieve near 100% selective oxidation of HMF to FDCA at low voltage (0.6V).

[0029] (2) By constructing a binary metal interface structure of NM / TM(OH)2 / C, this invention significantly improves the electrocatalytic oxidation performance of the catalyst at low potential (<1.0V) for biomass upgrading and plastic degradation. For example, at a low potential of 0.75V, the HMF oxidation current is as high as 200mA or more, which can realize the high-current and efficient electrocatalytic oxidation process for biomass upgrading and plastic degradation. Attached Figure Description

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention.

[0031] Figure 1 This is a high-resolution transmission electron microscope image of the Pd / Ni(OH)2 / C bimetallic catalyst of Example 1 of the present invention.

[0032] Figure 2 The catalyst in Example 2 of this invention was subjected to HMF oxidation CV test at room temperature using cyclic voltammetry.

[0033] Figure 3 The charge-time curve of the catalyst in Example 3 of this invention is obtained by electro-oxidation of HMF using the potentiostatic method at 0.75V vs. RHE.

[0034] Figure 4 The product distribution results were obtained by sampling the electrolyte after the HMF electrocatalytic oxidation reaction of the catalyst in Example 3 of the present invention at different voltages (0.3V, 0.4V, 0.5V, 0.6V, 0.75V, 0.9V).

[0035] Figure 5 The product distribution results are obtained from five consecutive cycle stability tests of Pd / Ni(OH)2 / C using the catalyst of Example 3 of this invention at a voltage of 0.75V vs. RHE. Detailed Implementation

[0036] First, it should be noted that the specific structure, features, and advantages of the present invention will be described in detail below by way of examples. However, all descriptions are for illustrative purposes only and should not be construed as limiting the present invention in any way. Furthermore, any single technical feature described or implied in the various embodiments mentioned herein can still be arbitrarily combined or deleted among these technical features (or their equivalents) to obtain more other embodiments of the present invention that may not be directly mentioned herein.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0039] Example 1

[0040] Preparation of Ni(OH)2 / C, Pd / Ni(OH)2 / C, and Pd / Ni(OH)2 / C etching catalysts.

[0041] Preparation method of Ni(OH)2 / C: Weigh 0.717g Ni(NO3)2·6H2O into a 250mL Erlenmeyer flask, add 12.5mL ethanol and 82.5mL deionized water, and stir at room temperature for 15 minutes; weigh 0.125g carbon black into the Erlenmeyer flask, sonicate for 15 minutes, then stir for 60 minutes, add the prepared NaOH solution, adjust the pH of the solution to 13.5, seal the solution in the Erlenmeyer flask, and stir for 20 hours; filter and wash, wash several times with ethanol and deionized water, place in a vacuum drying oven at 60℃ for 12 hours, grind, weigh, and obtain Ni(OH)2 / C.

[0042] Preparation method of Pd / Ni(OH)2 / C: Take 0.084g of Ni(OH)2 / C prepared by the above method into a beaker, add deionized water to dilute to 200mL; add 5.238mL of Na2PdCl4·6H2O solution with a concentration of 19mg / mL dropwise, stir for 20 hours; filter and wash, wash several times with ethanol and deionized water, put into a vacuum drying oven at 60℃ and dry for 12 hours, grind, and after in-situ electrochemical reduction at 0-0.8V for 200 cycles, scrape off and dry to obtain Pd / Ni(OH)2 / C.

[0043] Preparation method of Pd / Ni(OH)2 / C-etching: Transfer 0.035g of the above Pd / Ni(OH)2 / C solution into a beaker, add 25mL of 0.5mol / L dilute nitric acid solution, stir mechanically at room temperature for 1.5 hours to remove nickel hydroxide, filter and wash, wash several times with ethanol and deionized water, place in a vacuum drying oven at 60℃ for 12 hours, grind, weigh, and obtain the etched Pd / Ni(OH)2 / C-etched material.

[0044] Figure 1 This is a transmission electron microscope (TEM) image of the Pd / Ni(OH)2 / C bimetallic catalyst. Figure 1 The lattice fringe spacing of Pd is 0.225 nm, the average particle size of the Pd catalyst is about 2 nm, it is supported on the surface of nickel hydroxide and the catalyst does not show obvious aggregation.

[0045] Example 2

[0046] Electrocatalytic oxidation of HMF was carried out using the catalyst prepared in Example 1 and commercial Pd / C.

[0047] Pd / Ni(OH)2 / C was used as a catalyst: a 1 mol / L KOH solution was prepared as the cathode electrolyte (20 mL), and a 1 mol / L KOH + 50 mmol / L HMF solution was prepared as the anolyte (20 mL). These solutions were then transferred to a three-electrode system (H-type electrolytic cell) using carbon paper (1 cm²). 2 A platinum foil electrode was used as the working electrode, a mercury / mercury oxide electrode (Hg / HgO) as the counter electrode, and a mercury / mercury oxide electrode as the reference electrode. 300 μL of catalyst ink (5 mg / mL, 0.25% Nafion) was dropped onto the working electrode surface. Both biomass upgrading and plastic electrooxidation were performed at room temperature using an electrochemical workstation (BioLogic EC-Lab). The reaction results are as follows: Figure 2 As shown.

[0048] Pd / Ni(OH)2 / C etching as a catalyst: The operation steps are the same as those described above for Pd / Ni(OH)2 / C as a catalyst, except that Pd / Ni(OH)2 / C is replaced with Pd / Ni(OH)2 / C etching. The reaction results are as follows. Figure 2 As shown.

[0049] Ni(OH)₂ / C as catalyst: The operation steps are the same as those for Pd / Ni(OH)₂ / C as catalyst, except that Pd / Ni(OH)₂ / C is replaced with Ni(OH)₂ / C. The reaction results are shown in the appendix. Figure 2 As shown.

[0050] Commercial Pd / C as catalyst: The operation steps are the same as those for Pd / Ni(OH)2 / C as catalyst, except that Pd / Ni(OH)2 / C is replaced with commercial Pd / C, the scan rate is 5 mV / s, and the reaction results are as follows. Figure 2 As shown.

[0051] from Figure 2 As can be seen, Ni(OH)₂ / C did not exhibit any reactivity in the electrocatalytic oxidation of HMF, while the Pd / Ni(OH)₂ / C bimetallic catalyst achieved a peak current density of 243.6 mA / cm². 2 It is a commercial Pd / C catalyst (55.6 mA / cm²). 2 The peak current density was 4.4 times that of the standard catalyst. More importantly, the catalytic performance of the single-metal catalyst (Pd / Ni(OH)2 / C-etching) was significantly reduced after etching away nickel hydroxide, with the peak current density dropping to 123.1 mA / cm². 2 This is because the Ni-O-Pd interface is crucial for the electrocatalytic oxidation of HMF, and the noble metal / transition metal hydroxide NM / TM(OH) x The interface effectively promotes efficient electrocatalytic oxidation of biomass and degradation of plastics at room temperature.

[0052] Example 3

[0053] Pd / Ni(OH)2 / C, Pd / Ni(OH)2 / C etching, and constant voltage product testing of commercial Pd / C catalysts.

[0054] The reaction conditions were as follows: a 1 mol / L KOH solution was prepared as the cathode electrolyte (20 mL), and a 1 mol / L KOH + 5 mmol / L HMF solution was prepared as the anolyte (10 mL). These solutions were then transferred to a three-electrode system (H-type electrolytic cell) and carbon paper (1 cm²) was used. 2 A platinum foil was used as the working electrode, a mercury / mercury oxide electrode (Hg / HgO) as the counter electrode, and a mercury / mercury oxide electrode as the reference electrode. 300 μL of catalyst ink (5 mg / mL, 0.25% Nafion) was dropped onto the surface of the working electrode. The reaction was tested using an electrochemical workstation (BioLogic EC-Lab) at a constant voltage of 0.75 V (vs. RHE) at room temperature. The reaction results are as follows: Figure 3 As shown.

[0055] from Figure 3 As can be seen, except for Ni(OH)2 / C (because Ni(OH)2 / C has no reactivity, so there are no product performance results), the charge transfer of each catalyst reaches its peak after about 5 hours of chronocurrent under a constant voltage of 0.75V, at which point the current tends to 0. Among them, Pd / Ni(OH)2 / C has the maximum value in the corresponding charge-time curve. Compared with the etched Pd / Ni(OH)2 / C, Ni(OH)2 / C and commercial Pd / C (10% Pd content) catalysts, the Pd / Ni(OH)2 / C bimetallic catalyst exhibits the highest reactivity.

[0056] Example 4

[0057] In Example 3, the electrolyte after HMF electrocatalytic oxidation reaction using the catalyst at different voltages (0.3V, 0.4V, 0.5V, 0.6V, 0.75V, 0.9V) was sampled and the product distribution was detected.

[0058] The product testing conditions are as follows:

[0059] The reaction was carried out at different voltages (0.3V, 0.4V, 0.5V, 0.6V, 0.75V, 0.9V) and at different coulombic values ​​(0C, 9.65C, 19.3C, 29.95C), with 50 μL samples taken and diluted to 1 mL with 950 μL of 5 mM ammonium formate aqueous solution (70%) + methanol (30%). The product was quantitatively detected by high-performance liquid chromatography (HPLC). After the column pressure stabilized, detection was performed using a full-wavelength UV detector with a diode array. The wavelength with the strongest product response and highest resolution (265 nm) was selected for spectral collection and quantification. Each injection volume was 10 μL. The product data were converted to standard samples and statistically analyzed.

[0060] Pd / Ni(OH)2 / C, Pd / Ni(OH)2 / C-etching, and product test results of commercial Pd / C catalysts at different voltages are as follows: Figure 4 .

[0061] from Figure 4As can be seen, the products of the reactions of various catalysts differed significantly at different voltages (0.3V, 0.4V, 0.5V, 0.6V, 0.75V, 0.9V). Among them, Pd / Ni(OH)₂ / C showed near 100% selectivity for FDCA at 0.75V, a significant improvement compared to etched Pd / Ni(OH)₂ / C (66.3% FDCA selectivity) and commercial Pd / C (37.1% FDCA selectivity). Literature review and comparison revealed that the Pd / Ni(OH)₂ / C bimetallic catalyst exhibited the highest FDCA product selectivity at low potentials (<1.0V), a level not previously reported.

[0062] Example 5

[0063] Cyclic stability testing and product detection were performed on Pd / Ni(OH)2 / C.

[0064] The stability test and product detection conditions were as follows: 20 mL of 1 mol / L KOH solution was prepared as the cathode electrolyte, and 10 mL of 1 mol / L KOH + 5 mmol / L HMF solution was prepared as the anolyte. These solutions were then transferred to a three-electrode system (H-type electrolytic cell) and examined using 1 cm thick carbon paper. 2 A platinum foil electrode was used as the working electrode, a mercury / mercury oxide electrode (Hg / HgO) as the reference electrode, and 300 μL of catalyst ink (5 mg / mL, 0.25% Nafion) was dropped onto the working electrode surface. Five chronoamperometry tests were performed at room temperature (0.75 V vs. RHE) using an electrochemical workstation (BioLogic EC-Lab), and 50 μL samples were collected at different coulombic values ​​(0°C, 9.65°C, 19.3°C, 29.95°C). The samples were diluted to 1 mL with 950 μL of 5 mM ammonium formate aqueous solution (70%) + methanol (30%). Quantitative analysis of the product was performed using high-performance liquid chromatography (HPLC). After column pressure stabilization, detection was performed using a full-wavelength UV detector with a diode array. The wavelength with the strongest product response and highest resolution (265 nm) was selected for spectral collection and quantification, with an injection volume of 10 μL each time. Product data from the five reactions were recorded, and standard conversion and statistical analysis were performed.

[0065] from Figure 5 As can be seen, the products of the Pd / Ni(OH)2 / C catalyst undergoing five consecutive cycles at a voltage of 0.75V show little difference, and the selectivity for FDCA is very high, close to 100%, indicating that the Pd / Ni(OH)2 / C catalyst has good stability and strong repeatability.

[0066] Example 6

[0067] Preparation of Pt / Co(OH)2 / C catalyst:

[0068] Preparation method of Co(OH)2 / C: Weigh 0.065g Co(NO3)2·6H2O into a 250mL Erlenmeyer flask, add 12.5mL of ethanol and 82.5mL of deionized water (purged with argon gas for 15 minutes to remove oxygen), and stir at room temperature for 30 minutes; weigh 0.125g of carbon black into the Erlenmeyer flask, sonicate for 30 minutes, then stir for 60 minutes, add the prepared NaOH solution, adjust the pH of the solution to 12, seal the solution in the Erlenmeyer flask, and stir for 20 hours; filter and wash, wash several times with ethanol and deionized water, place in a vacuum drying oven at 60℃ for 12 hours, grind, weigh, and obtain Co(OH)2 / C.

[0069] Preparation method of Pt / Co(OH)2 / C: Take 0.065g of Co(OH)2 / C prepared by the above method into a beaker, add deionized water to dilute to 200mL; add 7.5mL of H2PtCl6·6H2O solution with a concentration of 20mg / mL dropwise, stir for 10 hours; filter and wash, wash several times with ethanol and deionized water, put into a vacuum drying oven at 60℃ and dry for 24 hours, grind, and after electrochemical reduction at a constant potential (0.75V vs. RHE) for 200 cycles, scrape off and dry to obtain Pt / Co(OH)2 / C.

[0070] Preparation method of Pt / Co(OH)2 / C- etching: Transfer 0.035g of the above Pt / Co(OH)2 / C solution into a beaker, add 30mL of 0.5mol / L dilute nitric acid solution, stir mechanically at room temperature for 2.0 hours to remove cobalt hydroxide, filter and wash, wash several times with ethanol and deionized water, place in a vacuum drying oven at 60℃ for 24 hours, grind, weigh, and obtain the etched Pt / Co(OH)2 / C-.

[0071] Example 7

[0072] The catalyst prepared in Example 6 was used to conduct experiments on the electrocatalytic oxidative degradation of plastics.

[0073] First, 0.3M PET plastic was hydrolyzed in 2M KOH at 60℃ for 18 hours to obtain a PET hydrolysate solution. This solution was then prepared as a 1mol / L KOH + 1.0mol / L PET hydrolysate solution (terephthalic acid and ethylene glycol monomers), and transferred to a three-electrode system (H-type electrolytic cell, both cathodes are 1mol / L KOH solution). The electrolyte was 1mol / L KOH + 50mmol / L HMF. Carbon paper (1cm) was used for the electrolysis. 2A platinum foil electrode was used as the working electrode, a mercury / mercury oxide electrode (Hg / HgO) as the reference electrode, and 300 μL of catalyst ink (5 mg / mL, 0.25% Nafion) was dropped onto the surface of the working electrode. Biomass electro-oxidation was performed at room temperature using an electrochemical workstation (BioLogic EC-Lab).

[0074] Example 8

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

[0076] Nuclear magnetic resonance (NMR) analysis revealed that ethylene glycol in the PET hydrolysate underwent an anodic oxidation reaction, selectively breaking C-C bonds to form formate. Further addition of formic acid to the electrolyte and filtration yielded high-purity, high-value-added terephthalic acid. The filtrate was further concentrated and crystallized to obtain high-value-added potassium diformate (KDF). The purity of the product was confirmed by X-ray powder diffraction and single-crystal diffraction. The study found that different catalysts yielded varying results in the electrocatalytic oxidative degradation of plastics. Compared to etched Pt / Co(OH)₂ / C, Co(OH)₂ / C, and commercial Pt / C (20% Pt content) catalysts, the Pt / Co(OH)₂ / C bimetallic catalyst exhibited the highest reactivity.

[0077] It should be noted that the room temperature mentioned in the above embodiments refers to a temperature of 15-25°C; in addition, the atomic ratio of noble metals in the catalyst is obtained by ICP-OES testing and calculation.

[0078] In summary, this invention overcomes the shortcomings of the prior art and provides a method for constructing a binary metal interface structure of NM / TM(OH)2 / C. This method achieves rapid reaction rates, high selectivity of corresponding multi-electron products, good stability, and strong reproducibility in the electrocatalytic oxidation of biomass upgrading and plastic degradation at low potentials (<1.0V).

[0079] The above embodiments have provided a detailed description of the present invention, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A catalyst for the electrocatalytic selective oxidation of biomass upgrading and plastic degradation, characterized in that, This catalyst uses carbon-based materials as catalyst supports to support multi-component metals and multi-component metal hydroxides, forming a supported catalyst with a binary metal interface structure, denoted as NM / TM(OH)2 / C. NM is one or more of the noble metals Pt and Pd, and TM is one or more of the transition metals Ni and Co. The loading of NM is 0.5wt%-35wt%, and the loading of TM is 1wt%-30wt%. The preparation method of the catalyst includes the following steps: (1) Take a transition metal salt solution and add a coordination solvent, stir, and then add a catalyst support and stir; (2) Add an alkaline solution to the solution obtained in step (1) to adjust the pH of the solution; And undergo mechanical stirring reaction; (3) After filtration, washing, centrifugation and drying, a sample TM(OH)2 / C with transition metal loaded on a carrier was obtained; (4) Disperse the TM(OH)2 / C sample obtained in step (3) in one or two noble metal precursor solutions and stir continuously. The precipitation reaction is carried out at room temperature. Then, the catalyst NM-O is obtained by filtration, washing, centrifugation and drying. x / TM(OH)2 / C; (5) Take the NM-O obtained in step (4) x / TM(OH)2 / C was obtained by in-situ electrochemical reduction to NM / TM(OH)2 / C; The in-situ electrochemical reduction is carried out by cyclic voltammetry or potentiostatic method within the reduction potential range of the noble metal. The catalyst is used for the electrocatalytic oxidation of 5-hydroxyfurfural and PET plastic at a low potential of less than 1.0V.

2. The catalyst for selective electrocatalytic oxidation of biomass upgrading and plastic degradation according to claim 1, characterized in that, The coordination solvent in step (1) is ethanol, ethylene glycol, aniline or ethylenediamine.

3. The catalyst for selective electrocatalytic oxidation of biomass upgrading and plastic degradation according to claim 1, characterized in that, The catalyst support mentioned in step (1) is carbon black, activated carbon, graphene and its derivatives, carbon quantum dots or carbon nanotubes.

4. The catalyst for selective electrocatalytic oxidation of biomass upgrading and plastic degradation according to claim 1, characterized in that, The alkaline solution mentioned in step (2) is NaOH solution, sodium bicarbonate solution, sodium carbonate solution, hydrazine hydrate or NH3•H2O.

5. The catalyst for selective electrocatalytic oxidation of biomass upgrading and plastic degradation according to claim 1, characterized in that, The noble metal precursor solution mentioned in step (4) is a Pt-containing solution. 4+ Pd 2+ One or more of the following in aqueous solution.

6. The catalyst for electrocatalytic selective oxidation of biomass upgrading and plastic degradation according to claim 1, characterized in that, In step (2), the pH of the solution is adjusted to 8-14; the reaction is mechanically stirred at 5-35℃ for 0.5-48 h.

7. The catalyst for selective electrocatalytic oxidation of biomass upgrading and plastic degradation according to claim 1, characterized in that, In step (4), the precipitation reaction is carried out at room temperature for 0.5-24 h.

8. The application of the catalyst as described in claim 1, characterized in that, Used for electrocatalytic oxidation of 5-hydroxyfurfural and PET plastics at low potentials (less than 1.0V).

Images