Method for enhancing electro-catalysis formic acid oxidation and methanol oxidation by adsorbing sulfydryl or thiophenol molecules on surface of platinum catalyst

Abstract

The invention relates to a method for adsorbing sulfydryl or thiophenol molecules on the surface of a platinum catalyst to enhance electro-catalysis formic acid oxidation and methanol oxidation, in particular to a method for enhancing formic acid and methanol electro-oxidation reaction by modifying a platinum electrode with cysteamine molecules to form a platinum-cysteamine heterogeneous interface, and belongs to the technical field of catalytic energy. According to the invention, mercaptan / thiophenol molecules represented by cysteamine (CYS) are modified on the surfaces of platinum nanoparticles through chemical adsorption, so that a molecule-metal composite catalytic system with an optimized electronic structure is constructed. X-ray photoelectron spectroscopy, in-situ Raman spectroscopy and theoretical calculation prove that the catalytic performance of surface adsorption molecules is remarkably improved through a dual-action mechanism, on one hand, the electronic structure of platinum is regulated and controlled to reduce a reaction energy barrier, on the other hand, interface charge transfer kinetics is promoted, and the oxidation process of formic acid through a formate path is effectively optimized. The technical scheme has universality to various mercaptan / thiophenol molecular systems, and the strategy can also be used for improving the performance of methanol oxidation reaction. The invention provides a novel catalytic material system for developing efficient direct formic acid and methanol fuel cells, and has important application value in the field of clean energy conversion devices.

Description

Technical Field

[0001] The present invention relates to a method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation, and particularly relates to the formation of a platinum-cysteamine heterogeneous interface by modifying a platinum electrode with cysteamine molecules to enhance the electrooxidation reactions of formic acid and methanol, belonging to the technical field of catalytic energy. Background Art

[0002] The electrooxidation reaction of formic acid is an important research topic in the fields of energy conversion and catalytic chemistry, especially in direct formic acid fuel cells. As a small molecule fuel, formic acid has a relatively simple structure and the characteristics of being safe, non-toxic and having a high density of energy, and has a relatively broad development space as a direct liquid fuel cell. The electrooxidation of formic acid occurs on the anode catalyst, generally materials such as platinum (Pt) and palladium (Pd), releasing electrons on the surface of the catalyst and undergoing an oxidation reaction to be converted into CO2 and protons. Due to the simple molecular formula of formic acid, its oxidation reaction mechanism and oxidation process intermediates are relatively clear compared to methanol oxidation, and the formic acid oxidation process is included in the methanol oxidation path. The oxidation of formic acid is generally divided into direct oxidation and indirect oxidation (dehydration pathway). The direct oxidation path includes a direct transient path and a formic acid path (dehydrogenation pathway).

[0003] Generally speaking, due to the existence of the indirect path, some *CO is more likely to be adsorbed on the surface of the anode catalyst for formic acid oxidation. These *CO are fatal to catalyst materials such as Pt and Pd. Because *CO is prone to strong adsorption on the surface of Pt and Pd materials, causing catalyst poisoning and inactivation, thus affecting their performance. Currently, the main difficulties in the formic acid oxidation reaction are on the one hand the insufficient performance, and on the other hand the prevention of the occurrence probability of the indirect path. At present, there are mainly two mainstream methods to prevent the generation of *CO, so that the formic acid oxidation path is dominated by the direct path. One strategy is that the indirect oxidation of formic acid is due to its large continuous sites on the Pt-based surface, which are prone to generate *CO with extremely high adsorption. Therefore, to solve this problem, discontinuous Pt sites need to be created. From the aspect of catalyst preparation, methods such as self-terminating growth, molecular adsorption and single atoms can effectively isolate the sites, making the reaction dominated by the direct path. Another strategy is to introduce metals that can inhibit the generation of *CO or quickly oxidize *CO, such as silver, bismuth, tellurium, etc., to form Pt- and Pd-based alloyed materials to prevent the occurrence of the indirect path. Although various strategies have been developed to improve the performance of electrocatalytic formic acid oxidation, the preparation of composite catalysts is usually relatively complex and the reaction rate is still limited. Therefore, it is extremely important to develop a simple and efficient method to improve the performance of formic acid electrooxidation. The present invention proposes a method for modifying a platinum catalyst by molecular adsorption to enhance interfacial charge transfer and improve the reaction microenvironment. This method has high generality and is applicable to multiple systems, providing a new idea for the development of simple and efficient formic acid and methanol electrooxidation catalysts. Summary of the Invention

[0004] The technical problem solved by the present invention is: a method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation. The formic acid oxidation current density of the Pt-CYS of the present invention increased from the original platinum electrode by 7.02 times to 24.76 mA cm -2 , and the surface-adsorbed molecules optimized the oxidation process of formic acid through the formate path by adjusting the electronic structure of platinum and promoting interfacial charge transfer, improving the cyclic stability of the catalyst. This molecular modification strategy shows universal advantages for various thiol / thiophenol molecular systems. In addition, this strategy can also be used to enhance other electrocatalytic oxidation reactions, such as methanol oxidation reaction (MOR). The catalytic activity and stability of the catalyst Pt-CYS of the present invention are superior to those of the current commercial Pt / C catalyst.

[0005] To solve the above technical problems, the technical solution proposed by the present invention is: a method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation. The molecules are chemically adsorbed on the surface of the platinum catalyst by an impregnation method to form a metal-molecule composite catalytic system. Under a continuously energized state, the method for adsorbing molecules on the surface of the metal catalyst to promote the efficient formic acid reaction of the metal catalyst is as follows: First, a metal electrode is prepared on FTO glass by ion sputtering. Subsequently, the metal electrode is immersed in a 2 mL 2 μM molecular solution for 15 min. After immersion, it is rinsed 3 times with water and then dried. This catalyst is used as a working electrode to perform electrochemical performance tests of formic acid oxidation in a 100 mL electrolytic cell of a three-electrode system.

[0006] Preferably, the preparation process of the Pt-CYS catalyst: 12-15 mg of cysteamine (CYS) is added to 10 mL of ultrapure water and dissolved by ultrasonic treatment, and then diluted 5000 times. 2 mL of the solution is taken out and added to the platinum electrode and soaked for 15 min, and then taken out and rinsed 3 times with ultrapure water, with each rinsing time being 30 s. After each rinsing, it is dried, and the final drying completes the preparation of the Pt-CYS composite catalyst.

[0007] Preferably, the platinum electrode is prepared by ion sputtering.

[0008] Preferably, the specific preparation method of the platinum electrode is: a 1.5×0.5 cm 2 fluorine-doped tin oxide (FTO) glass is placed in a vacuum sputtering machine, and the sputtering current and time are set to 4 mA and 80 s, respectively. The sputtering vacuum is maintained at 7 Pa, and the sputtering atmosphere is argon. After sputtering, the FTO containing platinum nanoparticles is placed in an oven and annealed at 120 °C for 2 h to obtain the platinum electrode.

[0009] Preferably, the formic acid electrooxidation experiment process is as follows: Take the prepared Pt-CYS as the working electrode. This working electrode is placed in a three-electrode system, with a platinum mesh electrode as the counter electrode and Ag|AgCl used as the reference electrode. Put 50 mL of a mixed aqueous solution of 0.1 M HClO4 and 0.5 M HCOOH in a 100 mL three-electrode electrolytic cell, and perform cyclic voltammetry curve testing of the formic acid oxidation reaction from 0 to 1 V on an electrochemical workstation (CHI 630E, Shanghai Chenhua Instrument), with a scanning rate of 20 mV / s.

[0010] Preferably, the stability test process of the formic acid electrooxidation experiment is as follows: Take the prepared Pt-CYS as the working electrode. This working electrode is placed in a three-electrode system, with a platinum mesh electrode as the counter electrode and Ag|AgCl used as the reference electrode. Put 50 mL of a mixed aqueous solution of 0.1 M HClO4 and 0.5 M HCOOH in a 100 mL three-electrode electrolytic cell, and perform an i-t curve test on an electrochemical workstation (CHI630E, Shanghai Chenhua Instrument), with a voltage of 0.72 V and a time of 1 h.

[0011] Preferably, the methanol electrooxidation experiment process is as follows: Take the prepared Pt-CYS as the working electrode. This working electrode is placed in a three-electrode system, with a platinum mesh electrode as the counter electrode and Ag|AgCl used as the reference electrode. Put 50 mL of a mixed aqueous solution of 0.1 M HClO4 and 1.0 M CH3OH in a 100 mL three-electrode electrolytic cell, and perform cyclic voltammetry curve testing of the formic acid oxidation reaction from 0 to 1 V on an electrochemical workstation (CHI 630E, Shanghai Chenhua Instrument), with a scanning rate of 20 mV / s.

[0012] Advantages of the present invention:

[0013] 1. The adsorption of molecules can affect the microenvironment on the platinum surface. The chemisorption of molecules realizes efficient interfacial charge transfer through the Pt-S bond to enhance the formic acid electrooxidation reaction. Due to the presence of molecules strengthening the adsorption of key intermediates in formic acid oxidation, the selectivity of the direct path of the formic acid oxidation reaction is improved, thereby enhancing the conversion process of formic acid molecules.

[0014] 2. The adsorption method of cysteamine molecules is very simple and convenient, making this composite material have great potential value in many practical applications. The successful implementation of this patent will provide a simple and efficient strategy for enhancing the electrocatalytic formic acid oxidation reaction of platinum catalysts, and solve the problems of the previous system being too complex and limited performance enhancement, providing the possibility for highly efficient and stable electrocatalysts for formic acid oxidation.

[0015] 3. The Pt-CYS prepared in this patent has the formic acid oxidation current density increased from the original platinum electrode by 7.02 times to 24.76 mA / cm² in the CV scan test. -2In addition, the electrocatalytic system is stable after 1 hour of catalysis, greatly improving the stability of the original platinum catalyst. The catalytic activity and stability of our composite photocatalyst are superior to those of the commercially reported Pt / C catalyst.

[0016] 4. The method of this patent has strong generality and is applicable to Pt-MES, Pt-MCH, and Pt-TGA structures, as well as Pt-PATP, Pt-PNTP, Pt-PHTP, Pt-PMBA, Pt-HTG, and Pt-NDM structures, all of which maintain a 3- to 7-fold enhancement in formic acid electrooxidation performance.

[0017] 5. The method of this patent can also be used for other electrocatalytic oxidation reactions. Adsorbing thiol and benzenethiol molecules on the surface of the platinum catalyst can increase the rate of electrocatalytic oxidation of methanol. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] Figure 1 It is a schematic diagram showing the enhancement of formic acid electrochemistry oxidation by cysteamine adsorbed on a platinum electrode.

[0020] Figure 2 It is the characterization of the Pt-CYS structure. (a) Scanning electron microscope (SEM) image of the platinum electrode. The inset shows the particle size distribution of PtNPs. (b) TEM and EDS spectra of Pt-CYS. (c) Raman spectra of the platinum electrode and Pt-CYS. (d) XRD spectra of the platinum electrode and Pt-CYS. (e-f) XPS Pt 4f spectra of bare Pt and Pt-CYS.

[0021] Figure 3 It is (a) cyclic voltammograms measured for Pt, Pt-MES, Pt-CYS, Pt-MCH, and Pt-TGA in formic acid solution. (b) Stability curves of Pt, Pt-MES, Pt-CYS, Pt-MCH, and Pt-TGA in formic acid solution.

[0022] Figure 4 It is (a) surface-enhanced Raman scattering spectra of Pt-CYS prepared with cysteamine at different soaking concentrations. (b) Relationship between cysteamine molecule concentration and the corresponding surface coverage on the platinum electrode. (c) Linear sweep voltammograms of Pt-CYS prepared in cysteamine solutions at different concentrations in FAOR. (d) Current density of platinum-cysteamine samples in FAOR at different cysteamine surface coverages.

[0023] Figure 5(a) Cyclic voltammetry curves of Pt, Pt-HTG, and Pt-NDM measured in formic acid solution. (b) Cyclic voltammetry curves of Pt, Pt-PATP, Pt-PNTP, Pt-PHTP, and Pt-PMBA measured in formic acid solution.

[0024] Figure 6 (a) Cyclic voltammograms of PtNPs, Pt-PATP, Pt-PNTP, Pt-PHTP, and Pt-PMBA measured in methanol solution. (b) Cyclic voltammograms of PtNPs, Pt-MES, Pt-CYS, Pt-MCH, and Pt-TGA measured in methanol solution. DETAILED DESCRIPTION

[0025] Example 1

[0026] 1.5×0.5cm 2 The FTO glass was placed in a vacuum sputtering machine with a sputtering current of 4 mA and a sputtering time of 80 seconds. The sputtering vacuum was maintained at 7 Pa in an argon atmosphere. After sputtering, the FTO containing platinum nanoparticles was annealed in an oven at 120°C for 2 hours to produce a platinum electrode.

[0027] In the molecular adsorption process, 12 to 15 mg of cysteamine was added to 10 mL of ultrapure water and ultrasonically dissolved, then diluted 5000 times. 2 mL of the solution was taken out and added to the platinum electrode to soak for 15 minutes. The electrode was then taken out and rinsed with ultrapure water three times, each rinsing time was 30 seconds. After each rinse, the electrode was blown dry. The final blow-drying completed the preparation of the Pt-CYS composite catalyst.

[0028] Our formic acid electrooxidation experimental process is:

[0029] The Pt-CYS prepared above was used as the working electrode, which was placed in a three-electrode system with a platinum mesh electrode as the counter electrode and Ag|AgCl as the reference electrode. 50 mL of a mixed aqueous solution of 0.1 M HClO4 and 0.5 MHCOOH was placed in a 100 mL three-electrode electrolytic cell. The 0-1 V cyclic voltammetry curve of the formic acid oxidation reaction was tested on an electrochemical workstation (CHI 630E, Shanghai Chenhua Instruments) with a scan rate of 20 mV / s.

[0030] like Figure 1 Schematic diagram of cysteamine adsorbed on platinum electrode to enhance the electrochemical oxidation of formic acid. Cysteamine molecules improve the FAOR performance of the platinum electrode by synergizing interfacial charge transfer and promoting the selection of the direct pathway for formic acid.

[0031] like Figure 2Structural characterization of the platinum electrode and Pt-CYS: First, we characterized the obtained platinum electrode and Pt-CYS catalyst by SEM, TEM, EDS, Raman, XRD, and XPS spectra. Scanning electron microscopy (SEM) and particle size diagrams showed that platinum nanoparticles were uniformly distributed on the FTO surface, with a uniform size of 5.0 ± 0.9 nm. Transmission electron microscopy (TEM) and elemental mapping images (EDS) showed that Pt, N, and S elements were uniformly distributed, and cysteamine was uniformly adsorbed on the surface of the platinum electrode. Raman tests showed the formation of Pt-S bonds, and cysteamine molecules were chemisorbed on the surface of platinum nanoparticles. The XRD results showed that Pt-CYS conformed to the crystal phase of the Pt (PDF#04-0802) card, and there was no obvious change in the crystal after cysteamine adsorption. Then, X-ray photoelectron spectroscopy (XPS) measurements were carried out to further study the surface chemical composition and electronic state of the prepared samples. The strong interaction between P platinum nanoparticles and cysteamine molecules was confirmed. Compared with platinum nanoparticles, the XPS Pt 4f 5 / 2 and 4f 7 / 2 peaks shifted approximately 0.2 eV towards lower binding energies. This shift indicates that electrons are transferred from the adsorbed cysteamine molecules to the Pt surface due to the strong interaction between Pt and S atoms. The percentage of Pt(0) in Pt-CYS was 35.1%, higher than 29.6% in the bare Pt sample, indicating that the coated cysteamine may inhibit the oxidation of the Pt surface. Due to the strong adsorption of cysteamine molecules, Pt atoms on the surface may be activated to accelerate the electrocatalytic FAOR process.

[0032] The performance and stability test process of this electrocatalytic formic acid oxidation experiment were as follows: The above-prepared Pt-CYS was taken as the working electrode. This working electrode was placed in a three-electrode system, with a platinum mesh electrode as the counter electrode and Ag|AgCl used as the reference electrode. 50 mL of a mixed aqueous solution of 0.1 M HClO4 and 0.5 M HCOOH was placed in a 100 mL three-electrode electrolytic cell, and cyclic voltammetry curve tests of formic acid oxidation reaction from 0 to 1 V were carried out on an electrochemical workstation (CHI 630E, Shanghai Chenhua Instrument) at a scanning rate of 20 mV / s. The stability test was carried out on an electrochemical workstation (CHI 630E, Shanghai Chenhua Instrument) for it curve tests at a voltage of 0.72 V for 1 h.

[0033] As Figure 3 shown, we found that in the cyclic voltammetry curve test, the Pt-CYS nanostructure could maintain high catalytic activity, reaching 24.76 mA·cm-2 at 0.67 V vs Ag|AgCl, which was 7.21 times that of the platinum electrode. The Pt electrodes adsorbed with MES, MCH, and TGA showed 20.52, 20.08, and 18.58 mA·cm -2The peak current density. These values are comparable to those of cysteamine-adsorbed Pt electrodes. Similar peak current densities indicate that the Pt-S bond (rather than the functional end group) mainly contributes to the improvement of Pt catalytic activity in FAOR. The stability test results show that cysteamine molecules grafted on the platinum surface can still exist stably for a certain period of time, continue to enhance the catalytic effect of platinum, and reduce the poisoning effect of the platinum electrode due to FAOR.

[0034] Comparative Example 1

[0035] The coverage of cysteamine molecules on the Pt surface has a significant impact on the obtained catalytic activity. By changing mainly the concentration of cysteamine for surface adsorption, different surface coverages can be obtained. As Figure 4 shown, first, a high concentration of 10 mM and a long soaking time of dozens of hours are used to ensure that the thiol molecules reach a saturated coverage (~100%) on the Pt surface. Similar procedures are widely used in the literature for the self-assembly of monolayer thiol molecules on metal surfaces. An obvious Raman peak is observed at 216 cm -1 which is attributed to the vibration of the Pt-S bond. The intensity of this peak is used as a reference for estimating the surface coverage of thiol molecules because the Raman intensity of this peak should be linearly related to the surface coverage of thiol molecules. At a low concentration of 0.4 μM, the measured surface coverage is 2.5%. When the cysteamine concentration increases to 2 μM and 5 μM, the surface coverages of cysteamine molecules increase to 7.1% and 8.1% respectively. At a low surface coverage of 2.5%, the catalytic activity of Pt increases slightly compared to bare Pt. The maximum oxidation current density (located at about 0.72 V vs Ag|AgCl) increases slightly from 1.35 mA cm -2 of bare Pt to 1.92 mA cm -2 . When the surface coverage of cysteamine further increases to 7.1%, the peak oxidation current density further increases to 3.57 mA cm -2 . However, when the cysteamine concentration continues to increase, the oxidation current density decreases instead. The maximum oxidation current density is obtained at a surface coverage of 7.1%. At low surface coverages, the limited adsorbed thiol molecules can only slightly promote the enhancement of FAOR. On the contrary, at very high surface coverages, the adsorbed thiol molecules may block the catalytic active sites, resulting in a significant reduction in the number of active sites, although the remaining active sites may experience a substantial increase in catalytic activity.

[0036] Comparative Example 2

[0037] There are many different types of thiol or benzenethiol molecules, which can also be grafted on the Pt surface and contribute to the improvement of FAOR performance. To test the versatility and tunability of our strategy, we tried a variety of thiol or benzenethiol molecules to enhance FAOR. As Figure 5As shown, catalysts (Pt-PATP, Pt-PNTP, Pt-PHTP, Pt-PMBA, Pt-HTG, and Pt-NDM) containing thiol group-structured benzenethiol molecules and long-chain thiols adsorbed on platinum electrodes were prepared to enhance the formic acid electrooxidation reaction performance. Research shows that these molecularly adsorbed platinum electrocatalysts also maintain a 3- to 7-fold enhancement in formic acid electrooxidation performance, which stems from the unique Pt-S bonds formed by the chemisorption of the molecules on the platinum surface. These results indicate that the thiol molecule adsorption strategy is universal in catalytic enhancement and can be applied to various systems of thiol-containing molecule-platinum electrodes.

[0038] Comparative Example 3

[0039] The universality of the present invention is also reflected in the enhancement effect of thiol molecules on other electrooxidation reactions. For example, Figure 6 as shown, taking the methanol oxidation reaction (MOR) as an example, on the Pt electrode grafted with thiophenol molecules, a significantly enhanced oxidation peak appears at ~0.65 V (vs Ag|AgCl) during the forward scan. Compared with the peak current density of the bare Pt electrode (0.83 mA cm-2), the Pt electrodes pre-grafted with PMBA, PATP, PNTP, and PHTP are increased to 5.32, 5.14, 5.02, and 4.32 mA cm-2 respectively, and the enhancement multiple of the PMBA-modified electrode reaches 6.4 times. Although the enhancement amplitude of the peak current during the reverse scan is slightly lower, a similar enhancement trend is still observed. These results indicate that this strategy is not only applicable to the enhancement of the formic acid oxidation reaction (FAOR), but can also be extended to other oxidation reaction systems.

[0040] The present invention is not limited to the specific technical solutions described in the above embodiments. Any technical solution formed by equivalent replacement falls within the protection scope required by the present invention.

Claims

1. A method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation, characterized in that : The method of molecular chemisorption on the surface of a platinum catalyst by impregnation to form a metal-molecule composite catalytic system, and promoting the efficient formic acid reaction catalyzed by the metal catalyst by adsorbing molecules on the surface of the metal catalyst under continuous power supply is as follows: First, a metal electrode is prepared on FTO glass by ion sputtering, and then the metal electrode is immersed in 2 mL of a 2 μM molecular solution for 15 min. After immersion, it is rinsed 3 times with water and then dried. This catalyst is used as a working electrode to conduct electrochemical performance tests for formic acid and methanol oxidation in a three-electrode system.

2. The method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation according to claim 1, characterized in that: The metal electrode is immersed in 2 mL of a 2 μM molecular solution for 15 min. After immersion, it is rinsed 3 times with water and then dried. The reaction is carried out in a three-electrode electrolytic cell for cyclic voltammetry curve testing.

3. The method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation according to claim 1, characterized in that: The molecules are chemisorbed on the surface of the platinum catalyst by self-assembly to form a heterojunction interface.

4. The method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation according to claim 1, characterized in that: The specific method for preparing the platinum-molecule composite structure electrocatalyst by impregnation is as follows: First, 12 - 15 mg of the molecules are added to 10 mL of ultrapure water and dissolved by ultrasonic treatment, and then diluted 5000 times. 2 mL of the solution is taken out and added to the platinum electrode and soaked for 15 min. Then it is taken out and rinsed 3 times with ultrapure water, with each rinsing time being 30 s. After each rinsing, it is dried. After the last drying, the platinum-molecule composite catalyst is prepared.

5. The method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation according to claim 1, characterized in that: The said molecules are cysteamine with a mercapto structure, sodium mercaptoethanesulfonate, mercaptoethanol, mercaptoacetic acid, aminothiophenol, nitrophenylthiol, mercaptobenzyl alcohol, mercaptobenzoic acid, n-heptanethiol, and n-dodecanethiol.

6. The method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation according to claim 1, characterized in that: The said platinum catalyst is made by sputtering on FTO glass in an Ar atmosphere by ion sputtering.

7. The method for adsorbing mercapto or thiophenol molecules on the surface of a platinum catalyst to enhance electrocatalytic formic acid oxidation and methanol oxidation according to claim 1, characterized in that: The process of formic acid electrooxidation experiment is: Take the above-prepared platinum electrode as the working electrode. Place this working electrode in a three-electrode system, use a platinum mesh electrode as the counter electrode, and Ag|AgCl as the reference electrode. Put 50 mL of a mixed aqueous solution of 0.1 M HClO4 and 0.5 M HCOOH in a 100 mL three-electrode electrolytic cell to conduct cyclic voltammetry curve testing of 0 - 1 V for formic acid oxidation reaction, with a scanning rate of 20 mV / s. For methanol electrooxidation, use the same experimental conditions as above, and change the electrolyte to a mixed aqueous solution of 0.1 M HClO4 and 1.0 M CH3OH.

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