Cs-doped FeOOH / BiVO4 photo-anode and preparation method thereof
By depositing FeOOH catalyst on the surface of BiVO4 photoanode and doping Cs, Cs doping FeOOH/BiVO4 photoanode is solved, and the problem of insufficient stability and catalytic activity in photoelectro-catalytic water decomposition is achieved, and efficient water oxidation is achieved Response and long-term stability.
Patent Information
- Application Number
- CN202411186269.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-28
- Publication Date
- 2024-12-10
AI Technical Summary
In the photocatalytic water decomposition of BiVO4, the photogenerated carrier recombination rate is large, the surface kinetics is weak, the catalytic oxidized water cracking capacity is poor, and the stability of FeOOH/BiVO4 is poor, which affects its application effect.
The FeOOH catalyst is deposited by photoelectrodeposition method on the surface of the BiVO4 photoanode and doped with Cs on the FeOOH/BiVO4 surface to form a Cs-doped FeOOH/BiVO4 photoanode to improve its stability and catalytic activity.
The catalytic activity and stability of photoelectro-catalytic water decomposition is improved, and the efficient water oxidation reaction is achieved. The photocurrent density reaches 4.21mA/cm2, and 99% stability is maintained during long-term use.
Smart Images
Figure CN119101933A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of photoelectrochemical technology, and particularly relates to a Cs-doped FeOOH / BiVO 4 Photoanode and method for preparing the same. Background Art
[0002] Currently, converting solar energy into hydrogen energy for storage and utilization is a clean and effective method. How to design photoanodes that can operate efficiently and stably is crucial to the utilization of global solar energy resources. Among the many metal oxide semiconductor photoanode materials with photocatalytic activity, BiVO 4 BiVO has become a widely studied and applied material for photoelectrocatalytic water splitting. 4 Semiconductors have limitations such as high recombination rate of photogenerated carriers, weak surface dynamics, and poor catalytic oxidation and water splitting ability. Therefore, we have used BiVO 4 Surface photodeposition of FeOOH can greatly improve its photocurrent performance, but its stability is poor, so Cs doping in FeOOH / BiVO 4 The photoanode surface can improve the stability of its photoelectrochemical PEC water splitting performance. Summary of the invention
[0003] To solve the above problems, a Cs-doped FeOOH / BiVO 4 The photoanode is prepared by the following steps:
[0004] 1) Preparation of BiVO 4 Photoanode;
[0005] 2) FeOOH / BiVO 4 Preparation of photoanode: Prepare ferrous sulfate solution and potassium borate solution, mix them evenly, and use chronoamperometry to measure the photoanode on BiVO 4 Photoelectrochemical deposition was carried out on the photoanode. After the deposition was completed, the photoanode was taken out, rinsed with deionized water, and dried with nitrogen to obtain FeOOH / BiVO 4 Photoanode;
[0006] 3) Cs-doped FeOOH / BiVO 4 Preparation of photoanode: Prepare 1.0 M cesium borate solution and use chronoamperometry to measure the photoanode on FeOOH / BiVO 4 Photoelectrochemical deposition was performed on the photoanode. After the deposition was completed, the photoanode was taken out, rinsed with deionized water, and dried with nitrogen to obtain Cs-doped FeOOH / BiVO 4 Photoanode.
[0007] The above-mentioned Cs-doped FeOOH / BiVO4 photoanode, BiVO 4The method for preparing the photoanode comprises the following steps:
[0008] 1) Pretreatment of FTO conductive glass: Clean the FTO glass with detergent, acetone, anhydrous ethanol and deionized water in sequence;
[0009] 2) Preparation of electroplating solution: 0.4MKI and 0.04MBi (NO 3 ) 3 ·5H 2 O was slowly poured into the nitric acid aqueous solution, stirred vigorously until completely dissolved, and the solution gradually turned orange-red. 0.23 M p-benzoquinone was prepared and dissolved in anhydrous ethanol by ultrasonic dissolution, and then mixed with the orange-red solution. After mixing, the solution turned dark red;
[0010] 3) Immerse FTO in the prepared electroplating solution with a size of 1cm×1cm as the working electrode, use Pt wire as the counter electrode, and use Ag / AgCl as the reference electrode; use a three-electrode system with an input voltage of -0.1Vvs.Ag / AgCl, electroplate for 300 seconds, and make a BiOI glass plate with uniform thickness;
[0011] 4) Prepare 0.4M vanadium acetylacetonate and dissolve it in 1.0mL DMSO. Mix well and take 20.0μL of it and drop it on the surface of BiOI glass plate. Place the drop-coated BiOI glass plate in a muffle furnace and heat it.
[0012] 5) Prepare 1M NaOH solution to remove BiVO 4 Surface V 2 O 5 , waiting for BiVO 4 After the board surface turns golden yellow, rinse with deionized water. 2 After drying, BiVO 4 Photoanode.
[0013] The above-mentioned Cs-doped FeOOH / BiVO 4 Photoanode, in step 2), the pH of the nitric acid aqueous solution is 1.7.
[0014] The above-mentioned Cs-doped FeOOH / BiVO 4 Photoanode, in step 4), the temperature in the muffle furnace is increased to 450° C. at a heating rate of 2° C. / min and heated for 2 hours.
[0015] The above-mentioned Cs-doped FeOOH / BiVO 4 Photoanode, in step 2), the concentration of ferrous sulfate solution is 8mM, and the concentration of potassium borate solution is 1.0M.
[0016] The above-mentioned Cs-doped FeOOH / BiVO 4In the photoanode, in step 2), when photoelectrodeposition is performed using a chronoamperometric method, the voltage is set to 0.6 V vs. RHE.
[0017] In the above-mentioned Cs-doped FeOOH / BiVO4 photoanode, in step 2), when the photoelectric deposition is performed using a chronoamperometric method, the deposition time is 6 min.
[0018] The above-mentioned Cs-doped FeOOH / BiVO 4 In the photoanode, in step 3), when photoelectrodeposition is performed using a chronoamperometric method, the voltage is set to 0.8 V vs. RHE.
[0019] In the above-mentioned Cs-doped FeOOH / BiVO4 photoanode, in step 3), when photoelectric deposition is performed using a chronoamperometric method, the deposition time is 167 min.
[0020] The above-mentioned Cs-doped FeOOH / BiVO 4 Application of photoanodes in photoelectrocatalytic water splitting.
[0021] The electrochemical performance test method is as follows:
[0022] 1) Using electrochemical workstation CHI660, FeOOH / BiVO was doped with Cs 4 The photoanode was used as the working electrode, the Pt wire was used as the counter electrode, the Ag / AgCl was used as the reference electrode, and the electrolyte was a potassium borate solution with a pH of 9.3.
[0023] 2) The scan rate of linear sweep voltammetry is 0.05 Vs -1 .
[0024] The beneficial effects of the present invention are as follows: the present invention adopts a simple preparation method of photoelectric deposition to prepare BiVO 4 A layer of amorphous FeOOH catalyst was uniformly deposited on the photoanode to obtain FeOOH / BiVO 4 In order to achieve long-term photoelectrochemical water splitting performance, Cs was doped in the outer layer as a co-catalyst to obtain Cs-doped FeOOH / BiVO 4 Photoanode. At 1.23V vs. RHE, the photocurrent density reaches 4.21mA / cm 2 . It not only improves the catalytic activity of photoelectrocatalytic water splitting, but also enhances the photoelectric stability and realizes efficient water oxidation reaction. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 It is BiVO 4 Transmission electron microscopy image of the photoanode.
[0026] Figure 2 It is FeOOH / BiVO4 Transmission electron microscopy image of the photoanode.
[0027] Figure 3 Cs doped FeOOH / BiVO 4 Transmission electron microscopy image of the photoanode.
[0028] Figure 4 is the X-ray diffraction pattern (XRD) of the prepared catalyst and photoanode.
[0029] Figure 5 It is FeOOH / BiVO 4 Linear sweep voltammograms of the photoanode after photocorrosion in potassium borate solution and cesium borate solution.
[0030] Figure 6 FeOOH / BiVO 4 Chronoamperometric curves (it) of the photoanode at 0.8 V vs. RHE in potassium borate solution and cesium borate solution. DETAILED DESCRIPTION
[0031] Example 1 Cs-doped FeOOH / BiVO 4 Preparation of photoanode
[0032] Pretreatment of FTO conductive glass: put the FTO glass into a solution containing detergent for ultrasonic cleaning for 30 minutes, rinse it with deionized water, then put it into an acetone solution for ultrasonic cleaning for 30 minutes, and finally put it into an anhydrous ethanol solution for ultrasonic cleaning for 30 minutes, blow dry it with nitrogen and set it aside;
[0033] Preparation of plating solution: 0.4MKI and 0.04MBi (NO 3 ) 3 ·5H 2 O was slowly poured into 50 mL of nitric acid aqueous solution, stirred vigorously until completely dissolved, and the solution gradually turned orange-red. 0.23 M p-benzoquinone was prepared and dissolved in 20 mL of anhydrous ethanol by ultrasonic dissolution, and then mixed with the orange-red solution. After mixing, the solution turned dark red;
[0034] BiVO 4Preparation of the photoanode: After the above-mentioned electroplating solution is prepared, immerse the FTO in the prepared electroplating solution with a size of 1cm×1cm as the working electrode, use Pt wire as the counter electrode, and use Ag / AgCl as the reference electrode; use a three-electrode system with an input voltage of -0.1Vvs.Ag / AgCl, electroplate for 300 seconds, and make a BiOI glass plate with uniform thickness. Then prepare 0.4M acetylacetonato vanadium oxydisperse in 1.0mL DMSO, mix well, take 20.0μL and drop it on the surface of the BiOI glass plate, place the drop-coated BiOI glass plate in a muffle furnace and heat it to 450℃ at a heating rate of 2℃ / min, and continue heating for 2 hours. After the heating process is completed, prepare 1MNaOH solution to remove BiVO 4 Surface V 2 O 5 , waiting for BiVO 4 After the board surface turns golden yellow, rinse with deionized water. 2 After drying, BiVO 4 Photoanode.
[0035] FeOOH / BiVO 4 Preparation of the photoanode: Prepare 1.0 M potassium borate solution and 8 mM ferrous sulfate solution, and use chronoamperometry to measure the photoanode on BiVO 4 Photoelectrochemical deposition was carried out on the photoanode for 6 min. After the deposition, the photoanode was taken out, rinsed with deionized water, and dried with nitrogen to obtain FeOOH / BiVO 4 Photoanode.
[0036] Cs doped FeOOH / BiVO 4 Preparation of photoanode: Prepare 1.0 M cesium borate solution and use chronoamperometry to measure the photoanode on FeOOH / BiVO 4 Photoelectrochemical deposition was carried out on the photoanode for 167 min. After the deposition, the photoanode was taken out, rinsed with deionized water, and dried with nitrogen to obtain Cs-doped FeOOH / BiVO 4 Photoanode.
[0037] Example 2 Electrochemical Performance Test
[0038] Electrochemical performance test: This experiment uses Shanghai Chenhua electrochemical workstation CHI660E, and three-electrode system to study the electrochemical performance. 4 The composite photoanode was used as the working electrode, the Pt wire was used as the counter electrode, the Ag / AgCl was used as the reference electrode, and the electrolyte was a potassium borate solution with a pH of 9.3. During the experiment, the xenon light intensity was measured to be 100 mW / cm 2 The scanning rate is 50mV·s -1 According to the Nernst equation, E RHE =EAg / AgCl +0.0591×pH+0.197V. During the experiment, all potentials measured by the reference Ag / AgCl electrodes need to be converted into potentials relative to the reversible hydrogen electrode (RHE).
[0039] Figure 1 BiVO 4 Transmission electron microscope image of the photoanode. It can be seen that the worm-like structure is 200nm and is evenly distributed, proving that BiVO 4 The photoanode was successfully prepared.
[0040] Figure 2 FeOOH / BiVO 4 Transmission electron microscopy image of the photoanode. Figure 1 Comparison. It can be seen that the amorphous catalyst is attached to BiVO 4 Photoanode surface, demonstrating FeOOH / BiVO 4 The composite photoanode was successfully prepared.
[0041] Figure 3 Cs doped FeOOH / BiVO 4 Transmission electron microscopy image of the photoanode. It can be seen that a layer of catalyst is attached to the FeOOH / BiVO 4 Photoanode surface, demonstrating Cs doping of FeOOH / BiVO 4 The composite photoanode was successfully prepared.
[0042] Figure 4 The X-ray diffraction patterns (XRD) of the prepared catalyst and photoanode. Figure 4 It can be found that loading other catalysts on the surface of bismuth vanadate does not change the structure of bismuth vanadate.
[0043] Figure 5 FeOOH / BiVO 4 The linear sweep voltammetric curve of the photoanode after photocorrosion in potassium borate solution and cesium borate solution is shown in Figure 2. Figure 5 By comparison, it can be found that the unmodified BiVO 4 The photoanode photocurrent density is the lowest, which is 1.90 mA / cm 2 , while FeOOH / BiVO 4 The photocurrent density of the composite photoanode was significantly improved to 4.21 mA / cm 2 The photocurrent density was improved by modifying the amorphous FeOOH catalyst, and efficient water oxidation reaction was achieved. However, after a period of water decomposition stability test, it was found that the Cs-doped FeOOH / BiVO 4The photocurrent density of the photoanode decreased less than that in the potassium borate solution, proving that Cs played a certain role in promoting electron transfer and thus improving water oxidation performance.
[0044] Figure 6 FeOOH / BiVO 4 The chronoamperometric curves (it) of the photoanode at 0.8 V vs. RHE in potassium borate solution and cesium borate solution, respectively. By comparison, it is found that within 10000 s, Cs-doped FeOOH / BiVO 4 The stability of the photocurrent density of the composite photoanode in cesium borate solution was maintained at 99%, which may be because Cs played a certain role in making the structure of the composite photoanode more stable, thereby improving the stability of the photoelectrode.
Claims
1. A Cs-doped FeOOH / BiVO4 photoanode, characterized in that: The preparation method comprises the following steps: 1) Preparation of BiVO4 photoanode; 2) Preparation of FeOOH / BiVO4 photoanode: prepare ferrous sulfate solution and potassium borate solution, mix them evenly, and use chronoamperometry to perform photoelectrochemical deposition on the BiVO4 photoanode. After the deposition, take out the photoanode, rinse it with deionized water, and blow dry it with nitrogen to obtain FeOOH / BiVO4 photoanode; 3) Preparation of Cs-doped FeOOH / BiVO4 photoanode: Prepare 1.0M cesium borate solution, and use chronoamperometry to perform photoelectrochemical deposition on the FeOOH / BiVO4 photoanode. After the deposition, remove the photoanode, rinse with deionized water, and blow dry with nitrogen to obtain a Cs-doped FeOOH / BiVO4 photoanode.
2. A Cs-doped FeOOH / BiVO4 photoanode according to claim 1, characterized in that: The preparation method of BiVO4 photoanode comprises the following steps: 1) Pretreatment of FTO conductive glass: Clean the FTO glass with detergent, acetone, anhydrous ethanol and deionized water in sequence; 2) Preparation of electroplating solution: 0.4MKI and 0.04MBi(NO3)3·5H2O were slowly poured into the nitric acid aqueous solution in sequence, and stirred vigorously until they were completely dissolved. The solution gradually turned orange-red. 0.23M p-benzoquinone was prepared and dissolved in anhydrous ethanol by ultrasonic dissolution. Then it was mixed with the orange-red solution. After mixing, the solution turned dark red. 3) Immerse FTO in the prepared electroplating solution with a size of 1cm×1cm as the working electrode, use Pt wire as the counter electrode, and use Ag / AgCl as the reference electrode; use a three-electrode system with an input voltage of -0.1Vvs.Ag / AgCl, electroplate for 300 seconds, and make a BiOI glass plate with uniform thickness; 4) Prepare 0.4M vanadium acetylacetonate and dissolve it in 1.0mL DMSO. Mix well and take 20.0μL of it and drop it on the surface of BiOI glass plate. Place the drop-coated BiOI glass plate in a muffle furnace and heat it. 5) Prepare 1M NaOH solution to remove V2O5 on the surface of BiVO4. After the surface of the BiVO4 plate turns golden yellow, rinse it with deionized water and blow dry it with N2 to obtain a BiVO4 photoanode.
3. A Cs-doped FeOOH / BiVO4 photoanode according to claim 2, characterized in that: In step 2), the pH of the nitric acid aqueous solution is 1.
7.
4. The Cs-doped FeOOH / BiVO4 photoanode according to claim 2, characterized in that: In step 4), the temperature in the muffle furnace is increased to 450° C. at a heating rate of 2° C. / min and heated for 2 hours.
5. The Cs-doped FeOOH / BiVO4 photoanode according to claim 1, characterized in that: In step 2), the concentration of the ferrous sulfate solution is 8 mM, and the concentration of the potassium borate solution is 1.0 M.
6. The Cs-doped FeOOH / BiVO4 photoanode according to claim 1, characterized in that: In step 2), when using chronoamperometry for photoelectrochemical deposition, the voltage is set to 0.6 V vs. RHE.
7. The Cs-doped FeOOH / BiVO4 photoanode according to claim 1, characterized in that: In step 2), when photoelectric deposition is performed using a chronoamperometric method, the deposition time is 6 minutes.
8. The Cs-doped FeOOH / BiVO4 photoanode according to claim 1, characterized in that: In step 3), when using chronoamperometry for photoelectrochemical deposition, the voltage is set to 0.8 V vs. RHE.
9. The Cs-doped FeOOH / BiVO4 photoanode according to claim 1, characterized in that: In step 3), when photoelectric deposition is performed using a chronoamperometric method, the deposition time is 167 min.
10. Use of a Cs-doped FeOOH / BiVO4 photoanode as claimed in claim 1 in photoelectrocatalytic water decomposition.