A CeO-based x Methods for suppressing charge recombination at the semiconductor / electrocatalyst interface using regulatory units
By introducing CeOx material at the semiconductor/electrocatalyst interface, the problem of charge recombination at the semiconductor/electrocatalyst interface in the prior art is solved, thus achieving a high-efficiency PEC water splitting system. This is achieved by leveraging the redox capabilities of CeOx at the semiconductor interface to realize efficient separation of photogenerated charges and increase photocurrent density.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHAANXI NORMAL UNIV
- Filing Date
- 2023-05-10
- Publication Date
- 2026-05-26
AI Technical Summary
In existing technologies, severe charge recombination at the semiconductor/electrocatalyst interface hinders the improvement of photoelectrochemical water splitting efficiency, requiring effective control units to suppress such charge recombination.
Semiconductors are electrodeposited on fluorine-doped tin dioxide (FTO) substrates, followed by electrodeposition of Ce(OH)x in cerium nitrate solution and calcination to CeOx. FeNiOOH or FeNi(OH)x is then deposited in a mixed solution to form semiconductor/CeOx/FeNiOOH or semiconductor/CeOx/FeNi(OH)x composite materials. The redox ability of CeOx is used to induce hole transfer.
This achieved efficient separation of photogenerated charges, increased photocurrent density, and formed an efficient PEC water splitting system with a significant increase in photocurrent density.
Smart Images
Figure CN116590740B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photoelectrochemical water splitting technology, specifically relating to a method for transferring holes using CeO2 material through electrodeposition and calcination. x This method, which introduces a regulatory unit onto the semiconductor-electrocatalyst interface, effectively suppresses charge recombination at the semiconductor / electrocatalyst interface, and can then be applied to the field of photoelectrochemical water splitting. Background Technology
[0002] The global energy situation is severe, with fossil fuel shortages and serious environmental pollution, prompting the development of sustainable energy supply. Hydrogen energy, as an ideal clean energy source, has attracted widespread attention. Photoelectrochemical (PEC) water splitting, which converts solar energy into hydrogen, is a promising method for sustainable energy supply. However, high PEC efficiency is often limited by slow surface catalysis and severe charge recombination, hindering its practical application. In recent years, coupling an electrocatalyst (transition metal hydroxide) to a photoanode to obtain an integrated photoelectrode system has proven to be the most effective strategy for improving PEC performance. However, due to the high recombination at the semiconductor / electrocatalyst interface, improving the PEC water oxidation efficiency to the desired level remains challenging. Researchers have confirmed that interface engineering has proven to be an effective strategy for reducing charge recombination at the semiconductor / electrocatalyst interface. Therefore, new regulatory units are needed to suppress the charge recombination problem at the semiconductor / electrocatalyst interface. Summary of the Invention
[0003] The purpose of this invention is to provide a method for effectively suppressing charge recombination at the semiconductor / electrocatalyst interface by introducing a hole transfer material that effectively separates photogenerated charges as a control unit onto the interface between the semiconductor and the electrocatalyst.
[0004] To achieve the above objectives, the technical solution adopted in this invention is as follows: first, a semiconductor is electrochemically deposited on a fluorine-doped tin dioxide (FTO) substrate; then, Ce(OH) is electrodeposited on the semiconductor in a cerium nitrate aqueous solution. x It is then roasted in air to cause Ce(OH)₂ to form ions. x Converted to CeO x Finally, CeO2 is dissolved in a mixed aqueous solution of nickel nitrate and ferrous sulfate. x FeNiOOH or FeNi(OH) is deposited on top. x Forming semiconductor / CeO x / FeNiOOH composite material or semiconductor / CeO x / FeNi(OH) x Composite material; the semiconductor is any one of BiVO4, reduced BiVO4 and Bi2WO6, which are abbreviated as BV, R-BV and BW respectively.
[0005] The above is based on CeO x A method for suppressing charge recombination at the semiconductor / electrocatalyst interface using a control unit specifically includes the following steps:
[0006] Step 1: Dissolve potassium iodide in water and stir, then add ground bismuth nitrate. After complete dissolution, adjust the pH to 1.5–2.0 by adding concentrated nitric acid. Mix the resulting solution with an ethanol solution of p-benzoquinone and stir for 5–10 min. Then, using a three-electrode system, with the FTO substrate as the working electrode, and the silver / silver chloride electrode and platinum sheet electrode as the reference and counter electrodes, respectively, electrodeposit BiOI at a constant potential. Afterward, dissolve vanadium acetylacetonate in dimethyl sulfoxide and drop it onto the BiOI. Keep the temperature constant at 450°C for 2 hours in air atmosphere, and cool to room temperature to obtain FTO / BV.
[0007] Alternatively, a three-electrode system can be used, with the above FTO / BV as the working electrode, and the silver / silver chloride electrode and platinum sheet electrode as the reference electrode and counter electrode, respectively, to reduce BV under constant potential to obtain FTO / R-BV.
[0008] Alternatively, the FTO substrate with electrodeposited BiOI and sodium tungstate aqueous solution were added to a high-pressure reactor and hydrothermally reacted at 120°C for 2 hours. After the reaction was completed, the substrate was naturally cooled to room temperature, washed with deionized water and dried. The substrate was then kept at 500°C in air for 2 hours and cooled to room temperature to obtain FTO / BW.
[0009] Step 2: Dissolve cerium nitrate in water and use a three-electrode system, with FTO / BV, FTO / R-BV, or FTO / BW as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, to perform electrodeposition of Ce(OH) at a constant potential. x The mixture was then heated at 300°C for 2 hours in air and cooled to room temperature to obtain FTO / BV / CeO. x or FTO / R-BV / CeO x or FTO / BW / CeO x ;
[0010] Step 3: Dissolve nickel nitrate and ferrous sulfate in water at a molar ratio of 3:1, and use a three-electrode system, FTO / BV / CeO x Using a silver / silver chloride electrode and a platinum sheet electrode as the working electrode, FeNiOOH was photoelectrodeposited under constant potential to obtain FTO / BV / CeO. x / FeNiOOH;
[0011] Alternatively, nickel nitrate and ferrous sulfate can be mixed in a 1:1 molar ratio and dissolved in water, using a three-electrode system, FTO / R-BV / CeO. x or FTO / BW / CeOx As the working electrode, a silver / silver chloride electrode and a platinum sheet electrode serve as the reference electrode and counter electrode, respectively, for electrodeposition of FeNi(OH) at a constant potential. x FTO / R-BV / CeO was obtained. x / FeNi(OH) x or FTO / BW / CeO x / FeNi(OH) x .
[0012] In step 1 above, it is preferable to perform electrodeposition of BiOI at a constant potential of -0.1 V for a deposition time of 300–500 s.
[0013] In step 1 above, it is preferable to reduce BiVO4 at a constant potential of -0.7 V for 30 to 50 seconds.
[0014] In step 2 above, it is preferable to dissolve cerium nitrate in water to make the concentration of cerium nitrate 16 mmol / L.
[0015] In step 2 above, it is preferable to perform the electrodeposition of Ce(OH) at a constant potential of -0.4 V. x The deposition time is 50–70 s.
[0016] In step 3 above, it is preferable to perform photoelectrodeposition of FeNiOOH at a constant potential of 0.3 V for a deposition time of 600–1200 s.
[0017] In step 3 above, it is preferable to perform the electrodeposition of FeNi(OH) at a constant potential of -0.4 V. x The deposition time is 50–70 seconds.
[0018] The beneficial effects of this invention are as follows:
[0019] 1. The method of the present invention is simple, low-cost, non-toxic, and highly reproducible.
[0020] 2. The hole transfer material CeO described in this invention x CeO is formed by electrodeposition and calcination, loading it between a semiconductor and an electrocatalyst to create a composite material. x With unique Ce 3+ / Ce 4+ Redox capabilities, in Ce 3+ and Ce 4+ The process involves switching between photogenerated charges, thereby inducing the transfer of photogenerated holes, effectively passivating surface defect states, and achieving efficient separation of photogenerated charges.
[0021] 3. This invention utilizes the hole transfer material CeO xIntroducing a semiconductor and electrocatalyst interface for photoelectrochemical water splitting to produce hydrogen, and constructing BV / CeO₂ compounds respectively. x / FeNiOOH、R-BV / CeO x / FeNi(OH) x and BW / CeO x / FeNi(OH) x The integrated system was then applied to the field of PEC water splitting. Under the same conditions, the photocurrent density of the integrated system reached 4.9 mA / cm². 2 5.58 mA / cm 2 and 0.032 mA / cm 2 (1.23 V vs. RHE), its BV / CeO x The photocurrent density of / FeNiOOH is higher than that of BV / Fe(OH) as a hole transfer material under the same conditions. x The photocurrent density of / FeNiOOH and BV / FeOOH / FeNiOOH was used to achieve effective charge separation, providing ideas for the design of efficient PEC water splitting systems. Attached Figure Description
[0022] Figure 1 It is BV(a) and BV / CeO x (b) SEM image.
[0023] Figure 2 It is BV(a) and BV / CeO x (b) Raman diagram.
[0024] Figure 3 It is BV(a) and BV / CeO x (b) XRD pattern.
[0025] Figure 4 It is BV, BV / FeNiOOH and BV / CeO x LSV diagram of / FeNiOOH.
[0026] Figure 5 It is R-BV, R-BV / FeNi(OH) x and R-BV / CeO x / FeNi(OH) x LSV diagram.
[0027] Figure 6 It is BW, BW / FeNi(OH) x and BW / CeO x / FeNi(OH) x LSV diagram.
[0028] Figure 7 It refers to BV, BV / FeNiOOH, and BV / Fe(OH). x LSV diagram of / FeNiOOH.
[0029] Figure 8 This is the LSV diagram of BV, BV / FeNiOOH, and BV / FeOOH / FeNiOOH. Detailed Implementation
[0030] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to the following embodiments.
[0031] Example 1
[0032] Step 1: Weigh 3.32 g of potassium iodide (99.9% purity), dissolve it in 50 mL of water and stir. Weigh 0.97 g of bismuth nitrate pentahydrate (99.9% purity) and grind it. Then, slowly add the ground bismuth nitrate pentahydrate to the potassium iodide aqueous solution. After complete dissolution, adjust the pH to 1.7 by adding concentrated nitric acid. Slowly mix the resulting solution with an ethanol solution of p-benzoquinone and stir for 5 min. Then, using a three-electrode system, with an FTO substrate (2.5 cm × 1.0 cm) as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, electrodeposit BiOI at a constant potential of -0.1 V for 300 s. Then, dissolve 0.2121 g of vanadium acetylacetonate in 4 mL of dimethyl sulfoxide to prepare a solution. Take 150 μL and drop it onto the BiOI. Heat the solution to 450 °C at a rate of 2 °C / min and hold it at that temperature for 2 minutes. h, cooled to room temperature to obtain FTO / BV.
[0033] Figure 1 Image a shows a scanning electron microscope (SEM) image of the obtained BV photoanode, clearly revealing its unique worm-like porous structure. Figure 2 a and Figure 3 a shows the X-ray diffraction (XRD) and Raman spectra of the obtained BV photoanode, confirming the successful preparation of BV.
[0034] Step 2: Dissolve cerium(III) nitrate hydrate in water to prepare a cerium nitrate solution with a concentration of 16 mmol / L. Using a three-electrode system, with FTO / BV as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, electrodeposit Ce(OH) at a constant potential of -0.4 V. x The deposition time was 50 s, yielding FTO / BV / Ce(OH)₂. xThe temperature was increased to 300 °C at 2 °C / min in an air atmosphere inside a muffle furnace, held for 2 hours, and then cooled to room temperature to obtain FTO / BV / CeO. x .
[0035] Figure 1 b shows the obtained BV / CeO x The SEM image of the photoanode shows that it has obvious wrinkles compared to the BV. Figure 2 b and Figure 3 b shows the obtained BV / CeO x The XRD and Raman spectra of the photoanode show no significant change compared to BV, which is because the deposited film is uniform and thin.
[0036] Step 3: Dissolve nickel nitrate hexahydrate and ferrous sulfate heptahydrate in water to prepare a mixed solution with a nickel nitrate concentration of 75 mmol / L and a ferrous sulfate concentration of 25 mmol / L. Use a three-electrode system with FTO / BV / CeO2. x Using a silver / silver chloride electrode and a platinum sheet electrode as the working electrode, FeNiOOH was photoelectrodeposited at a constant potential of 0.3 V for 600 s to obtain FTO / BV / CeO. x / FeNiOOH composite material.
[0037] Example 2
[0038] Step 1: Weigh 3.32 g of potassium iodide (99.9% purity), dissolve it in 50 mL of water and stir. Weigh 0.97 g of bismuth nitrate pentahydrate (99.9% purity) and grind it. Then, slowly add the ground bismuth nitrate pentahydrate to the potassium iodide aqueous solution. After complete dissolution, adjust the pH to 1.7 by adding concentrated nitric acid. Slowly mix the resulting solution with an ethanol solution of p-benzoquinone and stir for 5 min. Then, using a three-electrode system, with an FTO substrate (2.5 cm × 1.0 cm) as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, electrodeposit BiOI at a constant potential of -0.1 V for 300 s. Next, dissolve 0.2121 g of vanadium acetylacetonate in 4 mL of dimethyl sulfoxide to prepare a solution. Take 150 μL and drop it onto the BiOI. Heat the solution to 450 °C at a rate of 2 °C / min and hold it at that temperature for 2 minutes. h, cooled to room temperature to obtain FTO / BV. Then, using a three-electrode system, with FTO / BV as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, BV was reduced at a constant potential of -0.7 V for 30 s to obtain FTO / R-BV.
[0039] Step 2: Dissolve cerium(III) nitrate hydrate in water to prepare a cerium nitrate solution with a concentration of 16 mmol / L. Using a three-electrode system, with FTO / R-BV as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, electrodeposit Ce(OH) at a constant potential of -0.4 V. x The deposition time was 50 s, yielding FTO / BV / Ce(OH)₂. x The temperature was increased to 300 °C at 2 °C / min in an air atmosphere inside a muffle furnace, held for 2 hours, and then cooled to room temperature to obtain FTO / R-BV / CeO. x .
[0040] Step 3: Dissolve nickel nitrate hexahydrate and ferrous sulfate heptahydrate in water to prepare a mixed solution with a nickel nitrate concentration of 8 mmol / L and a ferrous sulfate concentration of 8 mmol / L. Use a three-electrode system with FTO / R-BV / CeO2. x As the working electrode, a silver / silver chloride electrode and a platinum sheet electrode were used as the reference electrode and counter electrode, respectively, to electrodeposit FeNi(OH) at a constant potential of -0.4 V. x The deposition time was 50 s, yielding FTO / R-BV / CeO. x / FeNi(OH) x Composite materials.
[0041] Example 3
[0042] Step 1: Weigh 3.32 g of potassium iodide (99.9% purity), dissolve it in 50 mL of water and stir. Weigh 0.97 g of bismuth nitrate pentahydrate (99.9% purity) and grind it. Then, slowly add the ground bismuth nitrate pentahydrate to the potassium iodide aqueous solution. After complete dissolution, adjust the pH to 1.7 by adding concentrated nitric acid. Slowly mix the resulting solution with an ethanol solution of p-benzoquinone and stir for 5 min. Then, using a three-electrode system, use an FTO substrate (2.5 cm × 1.0 cm) as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, to electrodeposit BiOI at a constant potential of -0.1 V for 300 s. Then, dissolve 1.32 g of sodium tungstate in 40 mL of deionized water to obtain a 0.1 M sodium tungstate aqueous solution. Add the FTO substrate with deposited BiOI and the sodium tungstate aqueous solution together to a high-pressure reactor and perform a hydrothermal reaction at 120℃ for 2 seconds. After the reaction was completed, the hydrothermal reactor was naturally cooled to room temperature, washed with deionized water and dried, and then heated to 500 ℃ at a heating rate of 2 ℃ / min and held at that temperature for 2 hours. After cooling to room temperature, FTO / BW was obtained.
[0043] Step 2: Dissolve cerium(III) nitrate hydrate in water to prepare a cerium nitrate solution with a concentration of 16 mmol / L. Using a three-electrode system, with FTO / BW as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, electrodeposit Ce(OH) at a constant potential of -0.4 V. x The deposition time was 50 s, yielding FTO / BV / Ce(OH)₂. x The temperature was increased to 300 °C at 2 °C / min in an air atmosphere inside a muffle furnace, held for 2 hours, and then cooled to room temperature to obtain FTO / BW / CeO. x .
[0044] Step 3: Dissolve nickel nitrate hexahydrate and ferrous sulfate heptahydrate in water to prepare a mixed solution with a nickel nitrate concentration of 8 mmol / L and a ferrous sulfate concentration of 8 mmol / L. Use a three-electrode system with FTO / BW / CeO₂. x As the working electrode, a silver / silver chloride electrode and a platinum sheet electrode were used as the reference electrode and counter electrode, respectively, to electrodeposit FeNi(OH) at a constant potential of -0.4 V. x The deposition time was 50 s, yielding FTO / BW / CeO. x / FeNi(OH) x Composite materials.
[0045] Comparative Example 1
[0046] Step 1: Prepare FTO / BV according to Step 1 of Example 1.
[0047] Step 2: Dissolve ferrous sulfate heptahydrate in water to prepare a 16 mmol / L ferrous sulfate solution. Using a three-electrode system, with FTO / BV as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, Fe(OH) is electrodeposited at a constant potential of -0.4 V. x The deposition time was 50 s, yielding FTO / BV / Fe(OH)₂. x .
[0048] Step 3: Following the method in Step 3 of Example 1, in FTO / BV / Fe(OH) x Preparation of FTO / BV / Fe(OH) by photoelectrodeposition of FeNiOOH x / FeNiOOH.
[0049] Comparative Example 2
[0050] Step 1: Prepare FTO / BV according to Step 1 of Example 1.
[0051] Step 2: Dissolve ferrous sulfate heptahydrate in water to prepare a ferrous sulfate solution with a concentration of 0.1 mol / L. Using a three-electrode system, with FTO / BV as the working electrode, and silver / silver chloride electrode and platinum sheet electrode as the reference electrode and counter electrode, respectively, FeOOH is electrodeposited at a constant potential of 1.2 V for 60 s to obtain FTO / BV / FeOOH.
[0052] Step 3: Following the method in Step 3 of Example 1, prepare FTO / BV / FeOOH / FeNiOOH by photoelectrodeposition of FeNiOOH on FTO / BV / FeOOH.
[0053] To demonstrate the beneficial effects of this invention, the composite materials prepared in Examples 1-3 and Comparative Examples 1-2 were used for PEC water splitting. Specifically, a three-electrode system was used, with the composite material as the working electrode and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively. Photocurrent density was measured in a 1 M potassium borate aqueous solution at pH 9.5. The test results are shown below. Figures 4-8 .
[0054] Depend on Figure 4 It can be seen that BV / CeO x The photocurrent density of the FeNiOOH composite material reached 4.9 mA / cm². 2 (1.23 V vs. RHE), higher than the photocurrent density of BV and BV / FeNiOOH.
[0055] Depend on Figure 5 It can be seen that R-BV / CeO x / FeNi(OH) x The photocurrent density of the composite material reached 5.58 mA / cm². 2 (1.23 V vs. RHE), higher than R-BV and R-BV / FeNi(OH) x The photocurrent density.
[0056] Depend on Figure 6 It can be seen that BW / CeO x / FeNi(OH) x The photocurrent density of the composite material reached 0.032 mA / cm². 2 (1.23V vs. RHE), higher than BW and BW / FeNi(OH) x The photocurrent density.
[0057] Depend on Figure 7 It can be seen that BV / Fe(OH) x The photocurrent density of the FeNiOOH composite material reached 4.3 mA / cm². 2(1.23 Vvs.RHE).
[0058] Depend on Figure 8 As can be seen, the photocurrent density of the BV / FeOOH / FeNiOOH composite material reached 4.4 mA / cm². 2 (1.23 Vvs.RHE).
[0059] As can be seen from the above, the BV / CeO constructed in this invention... x / FeNiOOH、R-BV / CeO x / FeNi(OH) x and BW / CeO x / FeNi(OH) x The integrated system, applied to the field of PEC water splitting, achieved a photocurrent density of 4.9 mA / cm² under the same conditions. 2 5.58 mA / cm 2 and 0.032 mA / cm 2 (1.23 V vs. RHE), significantly higher than their respective semiconductor / electrocatalyst systems. Meanwhile, BV / CeO x The photocurrent density of / FeNiOOH is also higher than that of BV / Fe(OH) under the same conditions. x The photocurrent density of / FeNiOOH and BV / FeOOH / FeNiOOH proves that CeO x It is a highly efficient hole transfer layer material that effectively modulates charge transfer and reaction kinetics at the semiconductor / electrocatalyst interface, achieving efficient PEC water splitting.
Claims
1. A CeO-based x The method for suppressing charge recombination at the semiconductor / electrocatalyst interface using a control unit is characterized by: First, a semiconductor is deposited on an FTO substrate; then, Ce(OH) is electrodeposited on the semiconductor in an aqueous solution of cerium nitrate. x It is then roasted in air to cause Ce(OH)₂ to form ions. x Converted to CeO x Finally, CeO2 is dissolved in a mixed aqueous solution of nickel nitrate and ferrous sulfate. x FeNiOOH or FeNi(OH) is deposited on top. x Semiconductor / CeO is formed on the substrate. x / FeNiOOH composite material or semiconductor / CeO x / FeNi(OH) x Composite materials; The semiconductor is any one of BiVO4, reduced BiVO4, and Bi2WO6, which are abbreviated as BV, R-BV, and BW respectively.
2. The CeO-based method according to claim 1 x The method for suppressing charge recombination at the semiconductor / electrocatalyst interface by a control unit is characterized by... The method includes the following steps: Step 1: Dissolve potassium iodide in water and stir, then add ground bismuth nitrate. After complete dissolution, adjust the pH to 1.5-2.0 by adding concentrated nitric acid. Mix the resulting solution with an ethanol solution of p-benzoquinone and stir for 5-10 minutes. Then, using a three-electrode system, with the FTO substrate as the working electrode, and the silver / silver chloride electrode and platinum sheet electrode as the reference and counter electrodes, respectively, electrodeposit BiOI at a constant potential. Afterward, dissolve vanadium acetylacetonate in dimethyl sulfoxide and drop it onto the BiOI. Keep the temperature constant at 450°C for 2 hours in air atmosphere, and cool to room temperature to obtain FTO / BV. Alternatively, a three-electrode system can be used, with the above FTO / BV as the working electrode, and the silver / silver chloride electrode and platinum sheet electrode as the reference electrode and counter electrode, respectively, to reduce BV under constant potential to obtain FTO / R-BV. Alternatively, the FTO substrate with electrodeposited BiOI and sodium tungstate aqueous solution were added to a high-pressure reactor and hydrothermally reacted at 120°C for 2 hours. After the reaction was completed, the substrate was naturally cooled to room temperature, washed with deionized water and dried. The substrate was then kept at 500°C in air for 2 hours and cooled to room temperature to obtain FTO / BW. Step 2: Dissolve cerium nitrate in water and use a three-electrode system, with FTO / BV, FTO / R-BV, or FTO / BW as the working electrode, and a silver / silver chloride electrode and a platinum sheet electrode as the reference and counter electrodes, respectively, to perform electrodeposition of Ce(OH) at a constant potential. x The mixture was then heated at 300°C for 2 hours in air and cooled to room temperature to obtain FTO / BV / CeO. x or FTO / R-BV / CeO x or FTO / BW / CeO x ; Step 3: Dissolve nickel nitrate and ferrous sulfate in water at a molar ratio of 3:1, and use a three-electrode system, FTO / BV / CeO x Using a silver / silver chloride electrode and a platinum sheet electrode as the working electrode, FeNiOOH was photoelectrodeposited under constant potential to obtain FTO / BV / CeO. x / FeNiOOH; Alternatively, nickel nitrate and ferrous sulfate can be mixed in a 1:1 molar ratio and dissolved in water, using a three-electrode system, FTO / R-BV / CeO. x or FTO / BW / CeO x As the working electrode, a silver / silver chloride electrode and a platinum sheet electrode serve as the reference electrode and counter electrode, respectively, for electrodeposition of FeNi(OH) at a constant potential. x FTO / R-BV / CeO was obtained. x / FeNi(OH) x or FTO / BW / CeO x / FeNi(OH) x .
3. The CeO-based method according to claim 2 x The method for suppressing charge recombination at the semiconductor / electrocatalyst interface using a control unit is characterized by: In step 1, BiOI is electrodeposited at a constant potential of -0.1V for 300–500 s.
4. The CeO-based method according to claim 2 x The method for suppressing charge recombination at the semiconductor / electrocatalyst interface using a control unit is characterized by: In step 1, BiVO4 is reduced at a constant potential of -0.7V for 30–50 seconds.
5. The CeO-based method according to claim 2 x The method for suppressing charge recombination at the semiconductor / electrocatalyst interface using a control unit is characterized by: In step 2, cerium nitrate is dissolved in water to make the concentration of cerium nitrate 16 mmol / L.
6. The CeO-based method according to claim 2 x The method for suppressing charge recombination at the semiconductor / electrocatalyst interface using a control unit is characterized by: In step 2, Ce(OH) is electrodeposited at a constant potential of -0.4V. x The deposition time is 50–70 seconds.
7. The CeO-based method according to claim 2 x The method for suppressing charge recombination at the semiconductor / electrocatalyst interface using a control unit is characterized by: In step 3, FeNiOOH is photoelectrodeposited at a constant potential of 0.3V for a deposition time of 600–1200 s.
8. The CeO-based method according to claim 2 x The method for suppressing charge recombination at the semiconductor / electrocatalyst interface using a control unit is characterized by: In step 3, FeNi(OH) is electrodeposited at a constant potential of -0.4V. x The deposition time is 50–70 seconds.