A bismuth platinum / bismuth titanium oxide electrode, its preparation method and application

Abstract

This invention belongs to the field of photoelectrocatalysis technology, and discloses a bismuth-platinum / bismuth-titanium oxide electrode, its preparation method, and its applications. This invention prepares a bismuth-dispersed platinum nanoparticle-modified titanium dioxide electrode using a layer-by-layer assembly method. This electrode possesses two adjacent platinum active sites and a bismuth-titanium dioxide heterojunction structure, exhibiting outstanding photoelectrocatalytic activity for the oxidation of methanol and formaldehyde. It can achieve the photoelectrocatalytic oxidation of methanol and formaldehyde through a direct oxidation mechanism. This method has advantages such as simple operation, controllable active sites, and low risk of poisoning, and has broad application prospects in methanol fuel cells and formaldehyde removal.

Description

Technical Field

[0001] This invention belongs to the field of photoelectrocatalysis technology, specifically relating to a bismuth platinum / bismuth titanium oxide electrode, its preparation method, and its application in the photoelectrocatalytic oxidation of methanol and formaldehyde. Background Technology

[0002] Platinum-based catalysts are widely used in fuel cells, pollutant degradation, and chemical synthesis due to their excellent catalytic oxidation performance. However, their high cost, limited availability, and susceptibility to poisoning restrict their practical application. Therefore, it is necessary to explore effective strategies to improve the catalytic activity and utilization efficiency of platinum-based catalysts. Specifically, the composition, morphology, particle size, and crystal structure of platinum can be controlled by altering the platinum preparation method, adding a support, and modifying the platinum surface, thereby regulating its catalytic activity and utilization rate.

[0003] Titanium dioxide is a low-cost, non-toxic, and highly photochemically stable semiconductor photocatalyst. As a supporting material, it can regulate the deposition distribution of platinum particles, improving platinum catalytic activity, reducing poisoning, and enhancing utilization and stability. Under ultraviolet light excitation, platinum-modified titanium dioxide composite catalyst electrodes exhibit high separation of photogenerated electrons and holes, achieving efficient conversion of light and chemical energy into electrical energy. Titanium dioxide crystals possess different crystal phase structures (anatase, rutile, etc.), with varying crystal facets, resulting in significantly different performance characteristics. Supporting platinum particles plays different regulatory roles. Since the oxidation reactions of methanol and formaldehyde in platinum-based catalysts primarily occur on the surface of platinum particles, introducing bismuth, which has a strong adsorption effect on reactive oxygen species, into the platinum / titanium dioxide electrode enhances the electro-oxidation and reduction activity of platinum, thereby increasing the photoelectrocatalytic performance of methanol and formaldehyde oxidation.

[0004] Currently, there are no studies reporting the regulatory effects of titanium dioxide carriers with different crystal ratios on the deposition distribution and active sites of platinum nanoparticles, nor are there any studies reporting the synergistic effects of titanium dioxide and bismuth with different crystal ratios on the aggregation morphology, active sites, and catalytic electro-oxidation activity of platinum particles in terms of methanol and formaldehyde. Summary of the Invention

[0005] To overcome the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a method for preparing a bismuth-platinum / bismuth-titanium oxide electrode. This method first uses titanium dioxide with different crystal ratios obtained by different temperature treatments as a carrier to regulate the deposition distribution of platinum particles. Then, bismuth is introduced by an irreversible adsorption-electrooxidation-reduction method. Through layer-by-layer assembly, a bismuth-platinum / bismuth-titanium oxide electrode with two adjacent platinum active sites and a bismuth-titanium dioxide heterojunction structure is prepared. This method overcomes the defect of easy poisoning of platinum-based catalysts and improves the utilization rate of platinum.

[0006] Another objective of this invention is to provide a bismuth platinum / bismuth titanium oxide electrode prepared by the above-mentioned preparation method; this electrode has outstanding photoelectrocatalytic activity for the oxidation of methanol and formaldehyde, enabling methanol and formaldehyde to undergo oxidation reactions through a direct oxidation pathway.

[0007] Another object of the present invention is to provide an application of the above-described bismuth platinum / bismuth titanium oxide electrode.

[0008] The objective of this invention is achieved through the following technical solution: A method for preparing a bismuth platinum / bismuth titanium oxide electrode includes the following steps: (1) Titanium dioxide powder obtained by calcining commercial titanium dioxide at 450~950℃ was ultrasonically dispersed with ethanol to obtain a titanium dioxide-ethanol suspension dispersion system; titanium dioxide electrode was obtained by soaking in the titanium dioxide-ethanol suspension dispersion system with indium tin oxide as the substrate. (2) Using the titanium dioxide electrode obtained in step (1) as the working electrode, the titanium sheet as the counter electrode, and the saturated calomel electrode as the reference electrode, a three-electrode system was assembled. The concentration of H2PtCl6 was 1.0 mmol / L. −1 The KCl concentration was 0.1 mol L. −1 In a mixed solution, platinum particles were electrodeposited on a titanium dioxide support by controlling the potential at −0.6 V for 200 s using a potentiostatic chronoamperometry method to obtain a platinum / titanium dioxide electrode. (3) Place the platinum / titanium dioxide electrode obtained in step (2) in a Bi(NO3)3 concentration of 0.03 mol L. −1 The concentration of HNO3 was 1.0 mol L. −1 The Bi(III) was assembled onto a platinum / titanium dioxide electrode by immersion in a mixed solution of [missing information - likely a specific substance or compound], and the resulting electrode was cleaned, dried, and then placed in a solution with a concentration of 0.1 mol / L [missing information - likely a specific concentration or compound]. −1 Cyclic voltammetry was performed in a NaOH solution, controlling the potential range of −0.75 ~ 0.6 V, with a scan rate of 0.05 V s. −1 The number of cycles is 5, and after cleaning and drying, a bismuth platinum / bismuth titanium oxide electrode is obtained.

[0009] In step (1), the commercial titanium dioxide is calcined at different temperatures to obtain titanium dioxide powders with different crystal ratios: calcination at 450℃ yields titanium dioxide powder with an anatase / rutile crystal ratio of 83:17; calcination at 650℃ yields titanium dioxide powder with an anatase / rutile crystal ratio of 59:41; and calcination at 950℃ yields titanium dioxide powder with an anatase / rutile crystal ratio of 1:99.

[0010] The calcination time in step (1) is 1 hour; the ultrasonic dispersion time is 40 minutes; the soaking is performed twice, with each soaking lasting 30 seconds, and the dispersant is removed by evaporation after soaking.

[0011] The soaking time in step (3) is 30 min.

[0012] A bismuth platinum / bismuth titanium oxide electrode prepared by the above-described preparation method.

[0013] The aforementioned bismuth-platinum / bismuth-titanium oxide electrode has two adjacent platinum active sites and a bismuth-titanium dioxide heterojunction structure.

[0014] The above-mentioned bismuth platinum / bismuth titanium oxide electrode is used in the photoelectrocatalytic oxidation of methanol or formaldehyde.

[0015] The above-mentioned bismuth platinum / bismuth titanium oxide electrode is used in the construction of methanol fuel cells.

[0016] The above-mentioned bismuth platinum / bismuth titanium oxide electrode is used in the field of formaldehyde removal.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention does not require cumbersome sample processing and complex electrode modification, thus avoiding the high cost, long time and complicated operation caused by sample processing and electrode modification.

[0018] (2) The present invention uses titanium dioxide as a support material and bismuth element modification, which can not only regulate the deposition morphology of platinum particles, enhance the active sites of platinum-based catalysts and the performance of catalytic oxidation of methanol and formaldehyde, but also has a synergistic catalytic effect.

[0019] (3) This invention provides a new method for synergistic enhancement of electrocatalytic activity of platinum-based catalysts by modifying metal oxides and doping elements, which has certain practical significance for application in fuel cells and pollutant degradation.

[0020] (4) The method of the present invention has the advantages of simple operation, controllable active sites and low risk of poisoning, and has broad application prospects in the fields of methanol fuel cells and formaldehyde removal. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the preparation process of the bismuth platinum / bismuth titanium oxide electrode of the present invention.

[0022] Figure 2 For different electrodes at 0.1 mol L −1 Cyclic voltammetry curves in NaOH solution, voltage range −0.75 to 0.6 V, scan rate 0.05 V s. −1The electrodes corresponding to curves 1, 2 and 3 are bismuth platinum / bismuth titanium oxide (titanium dioxide A:R=83:17), bismuth platinum / bismuth titanium oxide (titanium dioxide A:R=59:41) and bismuth platinum / bismuth titanium oxide (titanium dioxide A:R=1:99), respectively.

[0023] Figure 3 For different electrodes at 0.05 mol L −1 Methanol / 0.1 mol L −1 Cyclic voltammetry curves in NaOH solution, voltage range −0.6 ~ 0.2 V, scan rate 0.05 V s. −1 The electrodes corresponding to curves 1, 2 and 3 are bismuth platinum / bismuth titanium oxide (titanium dioxide A:R=83:17), bismuth platinum / bismuth titanium oxide (titanium dioxide A:R=59:41) and bismuth platinum / bismuth titanium oxide (titanium dioxide A:R=1:99), respectively. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0025] According to the design purpose of this invention, simple substitution of similar substances and changes in size and shape, such as changing the appearance of the electrode (e.g., changing it to a square or other shape), changing the type of catalytic oxidation reactants, changing the platinum deposition time, changing the electrode activation cyclic voltammetry range and number of cycles, changing the type of electrolyte solution, changing the amount of solute or the pH value of the solution, etc., should all fall within the scope of this invention; unless otherwise specified, the experimental methods used in the following examples are conventional methods existing in this technical field; unless otherwise specified, the materials and reagents used can be obtained commercially.

[0026] Examples 1-3 below illustrate the entire fabrication process of the bismuth-platinum / bismuth-titanium oxide electrode of the present invention, and its fabrication flow chart is shown below. Figure 1 As shown.

[0027] Example 1: Preparation of Titanium Dioxide Electrode (1) Commercial titanium dioxide was calcined at temperatures of 450℃, 650℃ and 950℃ for 1.0 hour. After calcination, it was cooled to room temperature to obtain titanium dioxide powders with different anatase / rutile (A:R) crystal ratios, which were then sealed and stored. Among them, the titanium dioxide powder obtained by calcination at 450℃ had an anatase / rutile (A:R) crystal ratio of 83:17, the titanium dioxide powder obtained by calcination at 650℃ had an anatase / rutile (A:R) crystal ratio of 59:41, and the titanium dioxide powder obtained by calcination at 950℃ had an anatase / rutile (A:R) crystal ratio of 1:99.

[0028] (2) Weigh 0.02 g of calcined titanium dioxide powder into a 5 mL sample tube, add 2 mL of anhydrous ethanol, and sonicate for 40 min to obtain titanium dioxide-ethanol suspension.

[0029] (3) Cut the indium tin oxide conductive glass with a width of 0.9 cm, and clean it by ultrasonic cleaning in anhydrous ethanol and distilled water for 15 min in sequence, and dry it at 40°C. Immerse the dried and clean indium tin oxide conductive glass in the titanium dioxide-ethanol suspension obtained in step (2) for 30 s, repeat the immersion twice, and dry it at 40°C to evaporate the dispersant, thus obtaining the titanium dioxide electrode.

[0030] Example 2: Preparation of Platinum / Titanium Dioxide Electrode Using the titanium dioxide electrode obtained in Example 1 as the working electrode, a titanium sheet as the counter electrode, and a saturated calomel electrode as the reference electrode, a three-electrode system was assembled. H₂PtCl₆ at a concentration of 1.0 mmol / L was added to the electrolytic cell. −1 The KCl concentration was 0.1 mol L. −1 A mixed solution was used to electrodeposit platinum particles on a titanium dioxide support using a constant voltage chronoamperometry method, controlling the voltage at −0.6 V and a deposition time of 200 s. After deposition, the electrode was immersed in distilled water to remove water-soluble residues and dried at 40°C to obtain the platinum / titanium dioxide electrode.

[0031] Example 3: Preparation of bismuth-platinum / bismuth-titanium oxide electrode The platinum / titanium dioxide electrode obtained in Example 2 was placed in a Bi(NO3)3 concentration of 0.03 mol / L. −1 The concentration of HNO3 was 1.0 mol L. −1 The sample was immersed in a mixed solution for 30 min, then rinsed with distilled water to remove water-soluble residues from the surface; it was then further transferred to a solution with a concentration of 0.1 mol / L.−1 In a NaOH solution, five cyclic voltammetric scans were performed in the potential range of −0.75 ~ 0.60 V at a scan rate of 0.05 V s. −1 The bismuth platinum / bismuth titanium oxide electrode was prepared by activation. The cyclic voltammetry curve of the fifth cycle during the activation process was compared. Figure 2 As shown, the following conclusions can be drawn: using titanium dioxide with different crystal ratios calcined at different temperatures as a support can synergistically regulate the active sites of platinum with bismuth, and the higher the calcination temperature of the titanium dioxide support, the higher the electrode activity of the resulting bismuth-platinum / bismuth-titanium oxide.

[0032] Example 4: Test of electro-oxidation of methanol and formaldehyde catalyzed by bismuth platinum / bismuth titanium oxide electrode Different electrodes were prepared using titanium dioxide with different crystal ratios obtained by calcining at different temperatures as described in Examples 1-3, denoted as bismuth platinum / bismuth titanium oxide (titanium dioxide A:R=83:17), bismuth platinum / bismuth titanium oxide (titanium dioxide A:R=59:41), and bismuth platinum / bismuth titanium oxide (titanium dioxide A:R=1:99). Cyclic voltammetry curves were measured for these three electrodes in methanol or formaldehyde solutions containing NaOH at a scan rate of 0.05 V / s. −1 The result is as follows Figure 3 As shown, the synergistic effect of titanium dioxide and bismuth enhances the activity of platinum electrocatalytic oxidation of methanol.

[0033] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a bismuth platinum / bismuth titanium oxide electrode, characterized in that... The following steps are included: (1) Titanium dioxide powder obtained by calcining commercial titanium dioxide at 450~950℃, specifically including one of the following methods: obtaining titanium dioxide powder with an anatase / rutile crystal ratio of 83:17 by calcination at 450℃, obtaining titanium dioxide powder with an anatase / rutile crystal ratio of 59:41 by calcination at 650℃, obtaining titanium dioxide powder with an anatase / rutile crystal ratio of 1:99 by calcination at 950℃; obtaining titanium dioxide powder with anatase / rutile crystal ratio of 1:99 by ultrasonic dispersion of the obtained titanium dioxide powder with ethanol to obtain a titanium dioxide-ethanol suspension dispersion system; obtaining a titanium dioxide electrode by immersing in the titanium dioxide-ethanol suspension dispersion system with indium tin oxide as a substrate; (2) Using the titanium dioxide electrode obtained in step (1) as the working electrode, the titanium sheet as the counter electrode, and the saturated calomel electrode as the reference electrode, a three-electrode system was assembled. The concentration of H2PtCl6 was 1.0 mmol / L. −1 The KCl concentration was 0.1 mol L. −1 In a mixed solution, platinum particles were electrodeposited on a titanium dioxide support by controlling the potential at −0.6 V for 200 s using a potentiostatic chronoamperometry method to obtain a platinum / titanium dioxide electrode. (3) Place the platinum / titanium dioxide electrode obtained in step (2) in a Bi(NO3)3 concentration of 0.03 mol L. −1 The concentration of HNO3 was 1.0 mol L. −1 The Bi(III) was assembled onto a platinum / titanium dioxide electrode by immersion in a mixed solution of [missing information - likely a specific substance or compound], and the resulting electrode was cleaned, dried, and then placed in a solution with a concentration of 0.1 mol / L [missing information - likely a specific concentration or compound]. −1 Cyclic voltammetry was performed in a NaOH solution, controlling the potential range of −0.75 ~ 0.6 V, with a scan rate of 0.05 V s. −1 The number of cycles is 5, and after cleaning and drying, a bismuth platinum / bismuth titanium oxide electrode is obtained.

2. The preparation method according to claim 1, characterized in that: The calcination time in step (1) is 1 hour; the ultrasonic dispersion time is 40 minutes; the soaking is performed twice, with each soaking lasting 30 seconds, and the dispersant is removed by evaporation after soaking.

3. The preparation method according to claim 1, characterized in that: The soaking time in step (3) is 30 min.

4. A bismuth platinum / bismuth titanium oxide electrode prepared by the preparation method of claim 1.

5. The bismuth platinum / bismuth titanium oxide electrode according to claim 4, characterized in that: The bismuth platinum / bismuth titanium oxide electrode has two adjacent platinum active sites and a bismuth-titanium dioxide heterojunction structure.

6. The application of the bismuth platinum / bismuth titanium oxide electrode according to claim 4 in the photoelectrocatalytic oxidation of methanol or formaldehyde.

7. The application of the bismuth platinum / bismuth titanium oxide electrode according to claim 4 in the construction of methanol fuel cells.

8. The application of the bismuth platinum / bismuth titanium oxide electrode according to claim 4 in the field of formaldehyde removal.

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