Catalyst with rich ptzn-znox interface active site for low potential production of benzoic acid and its preparation method and application

Abstract

The application discloses a PtZn-ZnO catalyst rich in low-potential benzene acid production x The application discloses a catalyst with a PtZn intermetallic compound structure and rich in PtZn-ZnO interface active sites, and a preparation method and application thereof. x The catalyst can significantly promote the oxidation efficiency of biomass-derived alcohol organic small molecules at a low potential (<0.9 V, relative to a reversible hydrogen electrode). x The PtZn-ZnO catalyst is applied to an electrocatalytic benzene methanol oxidation reaction, and benzene methanol can be electrocatalytically oxidized into benzene acid at a low potential of 0.725 V with a selectivity of 99.5%, and the electrocatalytic Faraday efficiency can reach 100%, and the catalyst has high conversion efficiency and excellent product selectivity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nanotechnology and biomass conversion electrocatalysis, and particularly relates to a PtZn-ZnO catalyst rich in interface active sites for low-potential production of benzoic acid and a preparation method and application thereof. x The present application belongs to the technical field of nanotechnology and biomass conversion electrocatalysis, and particularly relates to a PtZn-ZnO catalyst rich in interface active sites for low-potential production of benzoic acid and a preparation method and application thereof. BACKGROUND

[0002] Biomass valorization driven by renewable energy plays a crucial role in achieving energy storage and renewable fine chemicals production. Among them, hydroxyl-rich alcohol organic small molecules (such as: methanol, benzyl alcohol, ethanol, ethylene glycol, glycerol, furfuryl alcohol, glucose, lignin, etc.) as an important class of biomass derivatives, their value-added products have been widely studied and applied in the field of energy raw materials and chemical production. Taking biomass-derived benzyl alcohol (Ph-CH2OH) as an example, it has significant application potential because it can be effectively converted into high-value benzoic acid (Ph-COOH). As an important value-added chemical, benzoic acid is widely used in the fields of synthetic fibers, resins and corrosion prevention industry, and is a basic intermediate for many chemical products.

[0003] Traditionally, industrial production of benzoic acid mainly relies on toluene oxidation process, which usually requires high temperature (140-160℃), high pressure (0.2-0.3 MPa), and the use of chemical aids such as potassium permanganate (KMnO4), acidic solvents and bromide promoters. This process not only has harsh reaction conditions, but also involves complex purification operations (such as distillation and recrystallization), ultimately resulting in high carbon emissions, and there is an urgent need for more environmentally friendly and efficient alternative methods. In recent years, using electrocatalytic method to oxidize benzyl alcohol (BAOR) at room temperature by using water as oxygen source has become a promising alternative for the synthesis of benzoic acid. Compared with traditional aerobic oxidation and photocatalytic oxidation methods, electrocatalytic BAOR has many advantages such as mild reaction conditions, higher product purity, simplified separation and purification process, and higher catalyst recovery rate. More importantly, electrocatalytic BAOR only involves two oxidation products, which has been proven to be an ideal system for simplifying complex reaction networks and studying C-H bond activation mechanisms. This simplified reaction model provides a new research perspective for improving the conversion efficiency of biomass raw materials (such as alcohols, furfural, glycerol, etc.) and understanding their reaction mechanisms, especially for the conversion process of these basic chemical components.

[0004] Currently, the electrocatalytic oxidation of biomass-derived alcohol small organic molecules represented by benzyl alcohol usually requires a high oxidation potential, which leads to a large voltage input and energy consumption. To improve the selectivity and efficiency of benzyl alcohol oxidation reaction, researchers have carried out a lot of work, especially by developing new electrode materials to optimize the reaction performance. Transition metal oxides and hydroxides such as nickel and cobalt-based catalysts have been widely studied and shown good catalytic performance. On these catalysts, the electrocatalytic BAOR usually follows a nucleophilic oxidation reaction mechanism, which requires the generation of high-valence active metals at a high oxidation potential (>1.3V) and is reduced to a lower oxidation state by nucleophilic reagents (such as benzyl alcohol). However, reactions at high voltage still lead to high energy consumption and may trigger competitive side reactions such as oxygen evolution reaction or dissolution and degradation of electrode materials. (Reference: Energy Environ. Sci. 2020, 13(12), 4990-4999; Adv. Funct. Mater. 2023, 34(11), 2311611; ACS Catal. 2023, 13(7), 4272-4282) Therefore, it is of great practical significance to develop an electrocatalyst with high current density, low oxidation potential (<0.9V vs. reversible hydrogen electrode), high reaction rate, good stability, low cost, energy saving and environmental protection, and a catalyst and catalytic method for biomass conversion and selective electrocatalytic oxidation of biomass-derived alcohol small organic molecules. SUMMARY

[0005] The purpose of the present application is to address the problem of high operating potential of existing catalysts, and to provide a PtZn-ZnO x catalyst rich in interface active sites for low-potential production of benzoic acid and a preparation method and application thereof, which has high catalytic oxidation reaction rate and high benzoic acid product selectivity at low potential (<0.9V) and can be applied to other biomass-derived alcohol small organic molecules.

[0006] The technical problems of the present application are solved by adopting the following technical solutions:

[0007] A preparation method of a PtZn-ZnO x catalyst rich in interface active sites for low-potential production of benzoic acid, comprising the following steps:

[0008] (1) Impregnate zinc oxide powder in a precursor solution containing platinum ions to obtain a zinc oxide complex adsorbed with platinum ions;

[0009] (2) Disperse the complex of step (1) in a tris(hydroxymethyl) aminomethane solution, and then add dopamine hydrochloride and perform mechanical stirring reaction;

[0010] (3) the complex sample coated by the polydopamine layer is obtained through filtration, washing, centrifugation and drying;

[0011] (4) the complex sample in step (3) is placed in a tube furnace for high-temperature reduction reaction, and after reduction, it is cooled to room temperature to obtain a PtZn intermetallic compound loaded on nitrogen-doped carbon;

[0012] (5) the PtZn intermetallic compound in step (4) is exposed to air aging to obtain a PtZn-ZnO x catalyst.

[0013] Further, the mass-volume ratio of the zinc oxide in step (1) to the precursor solution containing platinum ions is 25-400 mg / mL.

[0014] Preferably, the mass-volume ratio of the zinc oxide in step (1) to the precursor solution containing platinum ions is 160 mg / mL.

[0015] Further, the precursor solution of platinum ions in step (1) is one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, platinum chloride, platinum acetylacetone, and tetraammine platinum nitrate, and the concentration of the precursor solution containing platinum ions is 0.05-0.3 g / mL.

[0016] Preferably, the precursor solution containing platinum ions in step (1) is chloroplatinic acid, and the concentration of the precursor solution containing platinum ions is 0.1 g / mL.

[0017] Further, the impregnation process in step (1) is that the zinc oxide powder is mixed with the precursor solution containing platinum ions, and then impregnated at room temperature for 12-48 hours until completely dry.

[0018] Preferably, the impregnation time in step (1) is 24 hours.

[0019] Further, the concentration of the tris(hydroxymethyl)aminomethane solution in step (2) is 5-20 mmol / L, and the mass ratio of the dopamine hydrochloride to the zinc oxide powder in step (2) is 0.1-3.

[0020] Preferably, the concentration of the tris(hydroxymethyl)aminomethane solution in step (2) is 10 mmol / L, and the mass ratio of the dopamine hydrochloride to the zinc oxide powder in step (2) is 0.5.

[0021] Further, the dispersion process in step (2) includes ultrasonic mixing and stirring mixing, and the duration of the mechanical stirring reaction in step (2) is 8-24 hours.

[0022] Further, the solvent used in the washing of step (3) is one or a mixture of deionized water and anhydrous ethanol; the centrifugal speed of step (3) is 5000-10000 rpm, the number of centrifugation is 1-3 times, and the centrifugation time of each time is 2-5 min; and the drying method of step (3) is oven drying at 60-80℃.

[0023] Further, the high-temperature reduction reaction condition of step (4) is that the hydrogen argon mixed gas is a protective atmosphere, the volume fraction of hydrogen is 5-10%, the temperature is raised to 600-800℃ at a heating rate of 5-10℃ / min and is kept for 0.5-2 hours.

[0024] Preferably, the high-temperature reduction reaction condition of step (4) is that the hydrogen argon mixed gas is a protective atmosphere, the volume fraction of hydrogen is 5%, the temperature is raised to 800℃ at a heating rate of 5℃ / min and is kept for 1 hour.

[0025] Further, the aging condition of step (5) is that the catalyst is exposed to air at room temperature for 1-10 hours.

[0026] The application provides a PtZn-ZnO x interface-rich catalyst for low-potential production of benzoic acid prepared by the above preparation method. The catalyst has a PtZn intermetallic compound structure, is a body-centered cubic (bcc) structure, and has a rich PtZn-ZnO x interface on the surface.

[0027] The PtZn-ZnO x interface-rich catalyst for low-potential production of benzoic acid prepared by the above method can be applied to electrocatalytic low-potential (<0.9V) oxidation of benzyl alcohol, methanol, ethanol, ethylene glycol, glycerol, isopropyl alcohol, diethylene glycol, furfuryl alcohol, 5-hydroxymethyl furfural, 4-hydroxy-3-methoxy benzyl alcohol and other organic small molecules derived from biomass.

[0028] Specifically, the method for electrocatalytic oxidation of benzyl alcohol or other biomass-derived alcohol small organic molecules using the above catalyst is as follows:

[0029] The catalyst powder is dispersed in a mixed solution of water, isopropyl alcohol and 5wt.% Nafion solution (the volume ratio of the three solutions is 10:9:1), and the mass-volume ratio of the catalyst to the mixed solution is 5-30 mg / mL. Catalyst ink is prepared by ultrasonic treatment for half an hour. 100-3000 uL of catalyst ink is dropped on a 1.0*0.5-1.0*2.0 cm 2Carbon paper as working electrode, platinum foil as counter electrode, mercury / mercury oxide electrode (Hg / HgO) as reference electrode, 1 mol / L KOH+0.05-0.2 mol / L substrate (such as: benzyl alcohol, methanol, ethanol, ethylene glycol, glycerol, isopropyl alcohol, diethylene glycol, furfuryl alcohol, 5-hydroxymethyl furfural, 4-hydroxy-3-methoxy benzyl alcohol, etc.) as electrolyte, all electrochemical tests, including: cyclic voltammetry test, linear voltammetry test, chronoamperometry electrolysis test, etc. are carried out at room temperature by using French Bio-logic EC-LAB electrochemical analyzer.

[0030] Compared with prior art solutions, the technical solutions of the present application have the following advantages and beneficial effects:

[0031] (1) The catalyst of the present application has the characteristics of simple operation and low cost by using impregnation method and H2 reduction method, and the obtained catalyst has uniform particle size (average particle size 2.38 nm) and good repeatability.

[0032] (2) The catalyst of the present application enhances the adsorption and activation of benzyl alcohol and reaction intermediates by constructing PtZn-ZnO x interface structure, promotes the generation of electrophilic OH * , reduces the energy barrier of Ph-CHO * and OH * coupling to generate Ph-C(OH)HO * , and significantly improves the performance of the catalyst in the electrocatalytic oxidation of benzyl alcohol at low potential. -2 In some embodiments, the catalyst of the present application has a starting potential as low as 0.19V (vs. reversible hydrogen electrode) in 1.0M KOH+0.1M Ph-CH2OH electrolyte, and the current density at 0.85V vs. RHE potential can reach 126mA cm -2 , which is twice that of commercial Pt / C.

[0033] (3) The catalyst of the present application can efficiently oxidize benzyl alcohol to produce benzoic acid at a low potential range (0.6-0.9V vs. RHE), achieving nearly 100% benzoic acid selectivity and 100% electrocatalytic Faraday efficiency, and showing high conversion efficiency and excellent product selectivity.

[0034] (4) The catalyst of the present application has universality in the oxidation reaction of various biomass-derived alcohol organic small molecules, such as the oxidation of benzyl alcohol, methanol, ethanol, ethylene glycol, glycerol, isopropyl alcohol, diethylene glycol, furfuryl alcohol, 5-hydroxymethyl furfural, 4-hydroxy-3-methoxy benzyl alcohol, etc., which provides ideas for designing electrocatalysts for selective activation of C-H bond and value-added conversion of organic small molecules. BRIEF DESCRIPTION OF DRAWINGS

[0035] The technical solutions of the present application will be described in further detail below in combination with the drawings and examples, but it should be understood that these drawings are designed only for the purpose of explanation, and thus do not limit the scope of the present application.

[0036] Figure 1 PtZn-ZnO prepared for Example 1 of the present application x High-resolution transmission electron micrograph of the catalyst.

[0037] Figure 2 PtZn-ZnO prepared for Example 1 of the present application x and PtZn-ZnO x Fourier-transformed X-ray absorption fine structure (FT-EXAFS) spectra of the (etched) catalysts.

[0038] Figure 3 PtZn-ZnO prepared for Example 1 of the present application x , PtZn-ZnO x (etched) and PtZn-ZnO after 5 cycles of reaction x X-ray photoelectron spectroscopy (XPS) spectra of the catalysts.

[0039] Figure 4 PtZn-ZnO prepared for Example 1 of the present application x , PtZn-ZnO x Linear voltammetry curves of the (etched) and commercial Pt / C catalysts in the oxidation reaction of benzyl alcohol in alkaline electrolyte (1 mol / L KOH).

[0040] Figure 5 PtZn-ZnO prepared for Example 1 of the present application x , PtZn-ZnO x Product distribution results of the electrolyte sampled after the electrocatalytic oxidation reaction of benzyl alcohol in alkaline electrolyte (1 mol / L KOH) at 0.725 V (vs. reversible hydrogen electrode) by the chronoamperometry method using the (etched) and commercial Pt / C catalysts.

[0041] Figure 6 PtZn-ZnO prepared for Example 1 of the present application x Product selectivity and conversion rate results of the electrocatalytic oxidation reaction of benzyl alcohol in alkaline electrolyte (1 mol / L KOH) at different voltages (0.625 V, 0.725 V, 0.825 V, vs. reversible hydrogen electrode) by the chronoamperometry method using the catalyst.

[0042] Figure 7 PtZn-ZnO prepared for Example 1 of the present application xThe Faraday efficiency of the catalyst in the electrocatalytic oxidation of benzyl alcohol in an alkaline electrolyte (1 mol / L KOH) at different voltages (0.625 V, 0.725 V, 0.825 V, relative to the reversible hydrogen electrode) was obtained by chronoamperometry.

[0043] Figure 8 PtZn-ZnO prepared in Example 1 of this invention x Catalyst (left) and PtZn-ZnO x The product distribution of the (etched) catalyst (right) after five consecutive cycles of cyclic stability testing of benzyl alcohol oxidation in an alkaline electrolyte (1 mol / L KOH) at a voltage of 0.725 V (relative to the reversible hydrogen electrode).

[0044] Figure 9 PtZn-ZnO prepared in Example 1 of this invention x High-resolution transmission electron microscopy (TEM) image and elemental distribution map of the catalyst after cycle stability testing.

[0045] Figure 10 PtZn-ZnO prepared in Example 1 of this invention x The product distribution results of the catalyst after five consecutive cycles of stability testing of benzyl alcohol oxidation in neutral electrolyte (1 mol / L PBS solution) at a voltage of 0.725 V (relative to the reversible hydrogen electrode).

[0046] Figure 11 PtZn-ZnO prepared in Example 1 of this invention x The catalyst was tested using linear voltammetry in an alkaline electrolyte (1 mol / L KOH) to detect the oxidation reactions of other biomass-derived alcohols and small organic molecules. Detailed Implementation

[0047] 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.

[0048] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and "comprising", when used in this specification, specify the presence of stated features, integers, steps, or components, but do not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.

[0049] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict.

[0050] Embodiment 1

[0051] Preparation of PtZn-ZnO x , PtZn-ZnO x (etched) catalyst

[0052] PtZn-ZnO x Preparation method of the catalyst: zinc oxide powder (80 mg) was immersed in H2PtCl6·6H2O solution (0.1 g / mL, 0.5 mL) by impregnation method, and the obtained powder was dispersed in tris(hydroxymethyl) aminomethane solution (10 mmol / L, 65 mL) after drying, and a light yellow suspension was obtained after stirring. Dopamine hydrochloride (40 mg) was added while stirring in the suspension, and the dopamine was polymerized by stirring at room temperature for 12 hours. The obtained product was washed several times with deionized water and ethanol, and was collected by centrifugation, and was dried in an oven at 60°C, and was placed in a quartz square boat with a cover, and was treated in a tube furnace at 800°C with hydrogen argon gas mixture as the protective atmosphere, wherein the volume fraction of hydrogen was 5%, and the temperature was raised at a rate of 5°C / min for 1 hour, to prepare a PtZn intermetallic alloy, and the sample was exposed to air for 5 hours to form PtZn-ZnO x .

[0053] PtZn-ZnO x Preparation method of the (etched) catalyst: PtZn-ZnO x was placed in HNO3 solution (5 mmol / L) and stirred for 12 hours, and the obtained sample was centrifuged and washed several times with deionized water, and was dried in an oven at 60°C to obtain the etched product PtZn-ZnO x (etched).

[0054] Figure 1 PtZn-ZnO xThe high resolution transmission electron microscopy (HRTEM) image of the catalyst shows that the catalyst particles expose the (110) plane of the PtZn intermetallic compound, forming a body-centered cubic (bcc) structure of the PtZn intermetallic compound, and the average particle size of the catalyst is 2.38 nm. Under the action of the polydopamine layer coating, the migration of Pt atoms and the aggregation of nanoparticles under a high-temperature reduction atmosphere are effectively inhibited. Figure 2 PtZn-ZnO x PtZn-ZnO x The Fourier transform X-ray absorption fine structure (FT-EXAFS) spectrum of the (etched) catalyst shows that a peak of Zn-O bond is observed near , indicating that ZnO x exists in the PtZn-ZnO x catalyst. x The significant decrease in the intensity of the Zn-O peak in the FT-EXAFS spectrum of the (etched) catalyst also proves that the ZnO x is removed after acid etching. Figure 3 PtZn-ZnO x PtZn-ZnO x and PtZn-ZnO x (etched) after 5 cycles of reaction. x The X-ray photoelectron spectroscopy (XPS) spectrum of the PtZn-ZnO 2+ catalyst shows that Zn 0 and Zn x exist in the PtZn-ZnO x catalyst, further confirming the existence of ZnO x in the PtZn-ZnO x catalyst, and the surface ZnO x and the PtZn-ZnO x interface of the (etched) catalyst are removed after nitric acid treatment.

[0055] Example 2

[0056] The PtZn-ZnO x , PtZn-ZnO x (etched) prepared in Example 1 and the commercial Pt / C catalyst were used to perform the electrocatalytic oxidation of benzyl alcohol experiments.

[0057] The PtZn-ZnO 2carbon paper as working electrode, platinum foil as counter electrode, mercury / mercury oxide electrode (Hg / HgO) as reference electrode, 25 mL of 1 mol / L KOH + 0.1 mol / L benzyl alcohol solution as electrolyte, linear voltammetry curve test was carried out in such three-electrode system at room temperature using French Bio-logic EC-LAB electrochemical analyzer. The test results are shown in Figure 4 .

[0058] PtZn-ZnO x (etched) etching as catalyst: the operation steps are the same as the above PtZn-ZnO x as catalyst, the step of PtZn-ZnO x is replaced by PtZn-ZnO x (etched), and the test results are shown in Figure 4 .

[0059] Commercial Pt / C as catalyst: the operation steps are the same as the above PtZn-ZnO x as catalyst, the step of PtZn-ZnO x is replaced by commercial Pt / C, and the test results are shown in Figure 4 .

[0060] Figure 4 The test results of benzyl alcohol oxidation reaction of PtZn-ZnO x , PtZn-ZnO x (etched) and commercial Pt / C catalysts by linear voltammetry at room temperature show that the starting potential of PtZn-ZnO x catalyst is 0.19 V (relative to reversible hydrogen electrode), which is 160 mV lower than that of commercial Pt / C; the peak current density of BAOR of PtZn-ZnO x at 0.85 V vs. RHE reaches 126 mA cm -2 , which is 1.4 times and 5 times of that of PtZn-ZnO x (etched) and commercial Pt / C respectively, indicating that the BAOR reaction activity of PtZn-ZnO x is the highest; the catalytic performance of PtZn-ZnO x after interface etching is significantly reduced, which shows that the interface of PtZn-ZnO x plays a promoting role in the catalytic activity of benzyl alcohol oxidation reaction.

[0061] Example 3

[0062] PtZn-ZnO x , PtZn-ZnO xPtZn-ZnO (etched) and commercial Pt / C catalysts were tested for product generation at constant potential.

[0063] The test conditions were as follows: 3 mL of catalyst ink (10 mg / mL, 0.25 wt.% Nafion) was dropped on 1.0*2.0 cm 2 carbon paper as working electrode, platinum foil as counter electrode, Hg / HgO electrode as reference electrode, 20 mL of 1 mol / L KOH + 5 mmol / L benzyl alcohol solution as electrolyte, in such a three-electrode system (H-type electrolytic cell), chronoamperometry was performed at room temperature using a French Bio-logic EC-LAB electrochemical analyzer at constant potential 0.725 V (vs. reversible hydrogen electrode). After 5 hours of testing, 200 μL of electrolyte was taken, neutralized with 2 mol / L hydrochloric acid, and then extracted with ethyl acetate. The supernatant (100 μL) after extraction was added to N,N-dimethylformamide (100 μL) and placed in a chromatographic bottle. After filtration with a 0.22 μm organic Nylon 66 membrane, the sample was analyzed by a Fuli gas chromatograph (GC 9790 Plus). An RB-FFAP capillary column (specifications 0.32 mm I.D. x 0.25 um Film x 30 m) and a flame ionization detector were used for analysis. The temperature was set to 300 °C, the inlet temperature was set to 270 °C, and the split ratio was 10:1. The test results are shown in Figure 5 .

[0064] PtZn-ZnO x (etched) as catalyst: the operation steps were the same as those described above for PtZn-ZnO x as catalyst, with PtZn-ZnO x replaced by PtZn-ZnO x (etched). The test results are shown in Figure 5 .

[0065] Commercial Pt / C as catalyst: the operation steps were the same as those described above for PtZn-ZnO x as catalyst, with PtZn-ZnO x replaced by commercial Pt / C. The test results are shown in Figure 5 .

[0066] Figure 5 The product distribution results of BAOR at 0.725 V (vs. reversible hydrogen electrode) for PtZn-ZnO x , PtZn-ZnO x (etched), and commercial Pt / C catalysts are shown in the table below. The results show that PtZn-ZnO xThe selectivity of the catalyst for benzoic acid is 99.5%, close to 100%, compared with PtZn-ZnO after etching x (etched)(87.1% benzoic acid selectivity) and commercial Pt / C (68.5% benzoic acid selectivity) catalysts, which indicates that the PtZn-ZnO x interface promotes the formation of the multi-electron product benzoic acid.

[0067] Example 4

[0068] The PtZn-ZnO catalyst prepared in Example 1 was applied x The product distribution of the electrolyte after the catalytic oxidation of benzyl alcohol by the catalyst at different voltages (0.625 V, 0.725 V, 0.825 V, relative to the reversible hydrogen electrode) was sampled and detected.

[0069] The test conditions were as follows: 3 mL of catalyst ink (10 mg / mL, 0.25 wt.% Nafion) was dropped on 1.0*2.0 cm 2 of carbon paper as the working electrode, platinum foil as the counter electrode, mercury / mercury oxide electrode (Hg / HgO) as the reference electrode, 20 mL of 1 mol / L KOH+5 mmol / L benzyl alcohol solution as the electrolyte, in such a three-electrode system (H-type electrolytic cell), using a French Bio-logic EC-LAB electrochemical analyzer to perform chronoamperometric test at room temperature at different voltages (0.625 V, 0.725 V, 0.825 V, relative to the reversible hydrogen electrode), 200 μL of the electrolyte was taken after 5 hours of testing, the obtained electrolyte was neutralized with 2 mmol / L hydrochloric acid, then extracted with ethyl acetate, and the supernatant (100 μL) after extraction was added with N,N-dimethylformamide (100 μL) and placed in a chromatographic bottle, filtered with a 0.22 μm organic Nylon 66 membrane, and then tested and analyzed using a Fuli gas chromatograph (GC9790Plus). A RB-FFAP capillary column (specifications 0.32 mm I.D. x 0.25 um Film x 30 m) was selected for analysis, a flame ionization detector was used for analysis, the temperature was set to 300°C, the inlet temperature was set to 270°C, and the split ratio was 10:1. The test results are shown in Figure 6 .

[0070] Figure 6 The PtZn-ZnO x The product selectivity and conversion rate of the PtZn-ZnO catalyst for the oxidation of benzyl alcohol at 0.625 V, 0.725 V, and 0.825 V (relative to the reversible hydrogen electrode), respectively, Figure 7 The results of the electrocatalytic Faraday efficiency, and the results show that the PtZn-ZnO xThe selectivity of the catalysts to benzoic acid at low potential (<0.9V) is all above 95%, and the electrocatalytic Faraday efficiency can reach 100%. By consulting the literature for comparison, the PtZn-ZnO x catalyst exhibits the highest product selectivity of benzoic acid at low potential (<0.9V) which has not been reported yet.

[0071] Example 5

[0072] The PtZn-ZnO x and PtZn-ZnO x (etched) catalysts were subjected to cyclic stability test and product detection.

[0073] The test conditions were as follows: 3mL of catalyst ink (10mg / mL, 0.25wt.% Nafion) was dropped on 1.0*2.0cm 2 of carbon paper as the working electrode, platinum foil as the counter electrode, mercury / mercury oxide electrode (Hg / HgO) as the reference electrode, 20mL of 1mol / L KOH+5mmol / L benzoic alcohol solution as the electrolyte, in such a three-electrode system (H-type electrolytic cell), using a French Bio-logic EC-LAB electrochemical analyzer to perform chronoamperometric test at room temperature and constant voltage 0.725V (relative to reversible hydrogen electrode) for 5 hours, then 200μL of electrolyte was taken, the obtained electrolyte was neutralized with 2mol / L hydrochloric acid, then extracted with ethyl acetate, and the supernatant (100μL) after extraction was added with N,N-dimethylformamide (100μL), placed in a chromatographic bottle, filtered with 0.22μm organic Nylon 66 membrane, and then tested and analyzed by using a Fuli gas chromatograph (GC 9790Plus). A RB-FFAP capillary column (specifications 0.32mm I.D. x 0.25um Film x 30m) was selected, and a flame ionization detector was used for analysis, with the temperature set to 300℃ and the injection port temperature set to 270℃, and the split ratio was 10:1. The test was repeated 5 times in the same way, and the test results are shown in Figure 8 .

[0074] Figure 8 The PtZn-ZnO x and PtZn-ZnO x The product distribution results of the cyclic stability test of the PtZn-ZnO xThe benzyl alcohol conversion (from 85% to 72%) and the benzoic acid selectivity (from 99% to 82%) slightly decreased after 5 BAOR cycles, while the PtZn-ZnO x (etched) catalyst maintained relatively stable conversion (about 75%) and selectivity (about 85%) in 5 BAOR cycles. Figure 9 The PtZn-ZnO x The high resolution transmission electron microscopy (HRTEM) images and element mapping of the catalyst after the cyclic stability test showed that, under the effect of the polydopamine layer coating, the PtZn-ZnO x The average size of the catalyst was about 2.0 nm, and no obvious agglomeration of the nanoparticles was observed. After the reaction, the PtZn-ZnO x The catalyst particles were obviously enriched with Pt, and therefore the PtZn-ZnO x The slight decrease in the cyclic stability of the catalyst can be attributed to the loss of ZnO x on the surface of the catalyst, which led to the formation of a thin Pt layer similar to pure platinum on the surface of the particles. The removal of ZnO x led to the attenuation of the performance of the catalyst, and the attenuation of the performance after 5 BAOR cycles confirmed that ZnO x on the surface of the catalyst was essential for improving the BAOR performance and stability. The PtZn-ZnO x catalyst of the present application had good cyclic stability. x The PtZn-ZnO x catalyst of the present application had good cyclic stability. x The PtZn-ZnO

[0075] Example 6

[0076] The PtZn-ZnO x catalyst prepared in Example 1 was subjected to cyclic stability test and product detection under neutral conditions (1 mol / L PBS solution).

[0077] The test conditions were as follows: 3 mL of catalyst ink (10 mg / mL, 0.25 wt.% Nafion) was dropped on 1.0*2.0 cm 2carbon paper as working electrode, platinum foil as counter electrode, silver / silver chloride electrode (Ag / AgCl) as reference electrode, 20 mL of 1 mol / L PBS + 5 mmol / L benzyl alcohol solution as electrolyte, in such a three-electrode system (H-type electrolytic cell), using French Bio-logic EC-LAB electrochemical analyzer to conduct chronoamperometric test at room temperature and constant voltage 0.725 V (relative to reversible hydrogen electrode), after 5 hours of testing, 200 μL of electrolyte was taken, the obtained electrolyte was extracted with ethyl acetate, and the supernatant (100 μL) after extraction was added into N,N-dimethylformamide (100 μL), placed in a chromatographic flask, filtered with 0.22 μm organic Nylon 66 membrane, and then tested and analyzed by using a Fuli gas chromatograph (GC 9790 Plus). A RB-FFAP capillary column (specification 0.32 mm I.D. x 0.25 um Film x 30 m) was selected for analysis, and a flame ionization detector was used, with temperature set at 300 °C, and inlet temperature set at 270 °C, and split ratio 10:1. The same test method was repeated for 5 times, and the test results are shown in Table 2. Figure 10

[0078] Figure 10 PtZn-ZnO x The product distribution results of the PtZn-ZnO catalyst in neutral electrolyte (1 mol / L PBS solution) under voltage 0.725 V (relative to reversible hydrogen electrode) for 5 times of cyclic stability test of benzyl alcohol oxidation reaction show that, compared with alkaline electrolyte, the benzyl alcohol conversion rate (100%), the selectivity of benzoic acid (100%) and the yield of benzoic acid (about 50%) of BAOR in neutral electrolyte remain relatively stable in 5 test cycles, because the ZnO x and the PtZn-ZnO x interface can remain stable in neutral electrolyte. This result indirectly proves that the ZnO x on the surface of the PtZn-ZnO x catalyst plays a crucial role in improving the performance and stability of BAOR.

[0079] Example 7

[0080] The PtZn-ZnO x catalyst prepared in Example 1 was used to test the oxidation reaction of other biomass-derived alcohol organic small molecules in alkaline electrolyte (1 mol / L KOH) by linear voltammetry.

[0081] The test conditions were as follows: 100 uL of catalyst ink (10 mg / mL, 0.25 wt.% Nafion) was dropped on a 1.0*0.5 cm 2 ​Carbon paper as working electrode, platinum foil as counter electrode, mercury / mercury oxide electrode (Hg / HgO) as reference electrode, 25 mL of 1 mol / L KOH + 0.1 mol / L substrate (methanol, ethanol, ethylene glycol, glycerol, isopropyl alcohol, diethylene glycol, furfuryl alcohol, 5-hydroxymethyl furfural, 4-hydroxy-3-methoxy benzyl alcohol) solution as electrolyte, in such a three-electrode system, linear voltammetry test was carried out at room temperature using a French Bio-logic EC-LAB electrochemical analyzer. The test results are shown in Figure 11

[0082] Figure 11 PtZn-ZnO x The linear voltammetry curves of the PtZn-ZnO catalyst in the oxidation reaction of other biomass-derived alcohol organic small molecules were compared before and after the addition of the catalyst, and the results showed that the PtZn-ZnO catalyst had good catalytic performance for methanol, ethanol, ethylene glycol, glycerol, isopropyl alcohol, diethylene glycol, furfuryl alcohol, 5-hydroxymethyl furfural and 4-hydroxy-3-methoxy benzyl alcohol at a low potential. x The PtZn-ZnO catalyst had good catalytic performance for methanol, ethanol, ethylene glycol, glycerol, isopropyl alcohol, diethylene glycol, furfuryl alcohol, 5-hydroxymethyl furfural and 4-hydroxy-3-methoxy benzyl alcohol at a low potential, which was reflected in the low starting potential (<0.4 V, relative to the reversible hydrogen electrode) and large current density, indicating that the PtZn-ZnO catalyst had good catalytic performance for the above-mentioned organic small molecules. x The PtZn-ZnO catalyst had good catalytic performance for methanol, ethanol, ethylene glycol, glycerol, isopropyl alcohol, diethylene glycol, furfuryl alcohol, 5-hydroxymethyl furfural and 4-hydroxy-3-methoxy benzyl alcohol at a low potential, which was reflected in the low starting potential (<0.4 V, relative to the reversible hydrogen electrode) and large current density, indicating that the PtZn-ZnO catalyst had good catalytic performance for the above-mentioned organic small molecules.

[0083] The above examples have been described in detail, but the content described is only the preferred embodiment of the present application and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made according to the scope of the present application should still be within the scope of the present application.​

Claims

1. A PtZn-ZnO-rich substrate for low-potential benzoic acid production x A method for preparing a catalyst with interfacial active sites, characterized in that, Includes the following steps: (1) Zinc oxide powder was impregnated in a precursor solution containing platinum ions to obtain a zinc oxide complex that adsorbs platinum ions. (2) Disperse the complex described in step (1) in a tris(hydroxymethyl)aminomethane solution, then add dopamine hydrochloride and perform a mechanical stirring reaction; (3) The composite sample coated with polydopamine layer was obtained by filtration, washing, centrifugation and drying; (4) The composite sample described in step (3) was placed in a tube furnace for high-temperature reduction reaction. After reduction, it was cooled to room temperature to obtain PtZn intermetallic compound loaded with nitrogen-doped carbon. (5) The PtZn intermetallic compound obtained in step (4) is exposed to air for aging to obtain PtZn-ZnO. x catalyst; The term "low potential" refers to a potential less than 0.9V.

2. The PtZn-ZnO-rich substrate for low-potential benzoic acid production according to claim 1 x A method for preparing a catalyst with interfacial active sites, characterized in that, The mass-to-volume ratio of zinc oxide to platinum ion-containing precursor solution in step (1) is 25–400 mg / mL.

3. A PtZn-ZnO-rich substrate for low-potential benzoic acid production according to claim 1 x A method for preparing a catalyst with interfacial active sites, characterized in that, The platinum-containing precursor solution in step (1) is one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, platinum chloride, platinum acetylacetonate, and tetraammineplatinum nitrate, and the concentration of the platinum-containing precursor solution is 0.05-0.3 g / mL.

4. A PtZn-ZnO-rich substrate for low-potential benzoic acid production according to claim 1 x A method for preparing a catalyst with interfacial active sites, characterized in that, The impregnation process in step (1) is as follows: after the zinc oxide powder is thoroughly mixed with the precursor solution containing platinum ions, it is impregnated at room temperature for 12 to 48 hours until completely dry.

5. A PtZn-ZnO-rich substrate for low-potential benzoic acid production according to claim 1 x A method for preparing a catalyst with interfacial active sites, characterized in that, The concentration of the tris(hydroxymethyl)aminomethane solution in step (2) is 5–20 mmol / L; the mass ratio of dopamine hydrochloride to zinc oxide powder in step (2) is 0.1–3.

6. A PtZn-ZnO-rich substrate for low-potential benzoic acid production according to claim 1 x A method for preparing a catalyst with interfacial active sites, characterized in that, The dispersion process in step (2) includes ultrasonic mixing and stirring mixing; the mechanical stirring reaction in step (2) lasts for 8 to 24 hours.

7. A PtZn-ZnO-rich substrate for low-potential benzoic acid production according to claim 1 x A method for preparing a catalyst with interfacial active sites, characterized in that, The solvent used for washing in step (3) is one of deionized water, anhydrous ethanol, or a mixture thereof; the centrifugation speed in step (3) is 5000-10000 rpm, the number of centrifugations is 1 to 3, and the time for each centrifugation is 2 to 5 minutes; the drying method in step (3) is drying in an oven at 60 to 80°C.

8. A PtZn-ZnO-rich substrate for low-potential benzoic acid production according to claim 1 x A method for preparing a catalyst with interfacial active sites, characterized in that, The conditions for the high-temperature reduction reaction in step (4) are as follows: a hydrogen-argon mixture is used as a protective atmosphere, wherein the hydrogen gas fraction is 5-10%, and the temperature is raised to 600-800℃ at a heating rate of 5-10℃ / min and held for 0.5-2 hours.

9. A PtZn-ZnO-rich compound for low-potential benzoic acid production prepared by the preparation method according to any one of claims 1-8. x Catalysts with interfacial active sites.

10. The PtZn-ZnO-rich material for low-potential benzoic acid production as described in claim 9 x The application of catalysts with interfacial active sites is characterized by, It is used for the electrocatalytic oxidation of benzyl alcohol, methanol, ethanol, ethylene glycol, glycerol, isopropanol, diethylene glycol, furfuryl alcohol, 5-hydroxymethylfurfural, and 4-hydroxy-3-methoxybenzyl alcohol at low potentials less than 0.9V.

Images