Ti and Zr-Fe2O3 photo-anode thin film capable of changing light absorption capacity of Fe2O3 photo-anode through doping and preparation method and application of Ti and Zr-Fe2O3 photo-anode thin film

Abstract

The invention relates to a Ti and Zr-Fe2O3 photo-anode film capable of changing the light absorption capacity of a Fe2O3 photo-anode through doping as well as a preparation method and application of the Ti and Zr-Fe2O3 photo-anode film. The light absorption capacity of Fe2O3 is optimized by doping proper elements (such as Ti and Zr), and the catalytic efficiency of Fe2O3 in solar water decomposition is remarkably improved. The doped elements effectively adjust the energy band structure of Fe2O3, the light absorption range of Fe2O3 is widened, and especially the absorption capacity of Fe2O3 in a visible light region is remarkably enhanced. The prepared photo-anode material shows excellent photoelectric conversion efficiency and can be applied to solar photoelectrochemical water decomposition. The material has the advantages of lower cost, higher stability and environmental protection property, and wide industrial application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectrochemistry and specifically relates to a method for changing Fe 2 O 3 Photoanode light absorption capacity of Ti,Zr-Fe 2 O 3 Photoanode film and its preparation method and application. Background Art

[0002] Photoelectrochemical water splitting technology is an important energy conversion technology that uses solar energy to drive water splitting to generate hydrogen. As a key component in photoelectrochemistry, photoanode materials directly affect the photoelectric conversion efficiency. 2 O 3 It has been widely studied as a photoanode material due to its abundant resources, low cost, and environmental friendliness, but its low light absorption capacity and photoelectrochemical efficiency limit its application in solar water splitting.

[0003] In order to increase Fe 2 O 3 The photoelectric conversion efficiency of Fe is low, so researchers try to improve its light absorption capacity and photoelectric activity by doping with other elements. Doping elements can adjust the 2 O 3 The band structure of Fe 2 O 3 There has been no significant breakthrough in improving the light absorption capacity of photoanodes, especially how to effectively enhance their light absorption capacity through doping remains an important research topic.

[0004] Therefore, the present invention proposes a method of changing Fe by doping 2 O 3 Preparation method of photoanode light absorption capacity, aiming to improve Fe 2 O 3 The light absorption efficiency of the photoanode is improved, and its photoelectrochemical performance is enhanced to solve the problem of Fe 2 O 3 Limitations of photoanodes in photoelectrochemistry. Summary of the invention

[0005] The present invention provides a method for changing Fe by doping 2 O 3 Preparation method and application of photoanode light absorption ability. By rationally selecting doping elements and controlling the doping amount, the Fe 2 O 3 The light absorption capacity of the doped quartz crystal is increased, thereby improving its efficiency in solar photoelectrochemistry. The doped elements include Ti and Zr.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A Ti,Zr-Fe 2 O 3 photoanode thin film with improved light absorption ability by doping Fe 2 O 3 The preparation method includes the following steps:

[0007] 1) Dissolve iron salt and urea in deionized water, add an ethanol solution of TiCl 4 , and stir to obtain a precursor solution; place the precursor solution and FTO conductive glass in a hydrothermal reactor, and through hydrothermal reaction, grow the precursor Ti-FeOOH on the conductive glass FTO to obtain the precursor Ti-FeOOH photoanode thin film;

[0008] 2) Place the Ti-FeOOH photoanode thin film in a precursor solution containing an ethanol solution of iron salt, urea, and ZrO(NO 3 ) 2 , and conduct hydrothermal reaction again to obtain a Ti,Zr-FeOOH photoanode;

[0009] 3) Calcinate Ti,Zr-FeOOH under air conditions to obtain a Ti,Zr-Fe 2 O 3 photoanode thin film.

[0010] In the above-mentioned Ti,Zr-Fe 2 O 3 photoanode thin film with improved light absorption ability by doping Fe 2 O 3 , in step 1), the iron salt is ferric chloride hexahydrate or ferric sulfate.

[0011] In the above-mentioned Ti,Zr-Fe 2 O 3 photoanode thin film with improved light absorption ability by doping Fe 2 O 3 , in step 1), the molar ratio of iron salt to urea is 1-2:1.

[0012] In the above-mentioned Ti,Zr-Fe 2 O 3 photoanode thin film with improved light absorption ability by doping Fe 2 O 3 , in step 1), by molar ratio, TiCl 4 : iron salt: urea is (0.75-1.25):40:40.

[0013] In the above-mentioned Ti,Zr-Fe 2 O 3Ti, Zr-Fe Photoanode Light Absorption Capacity 2 O 3 For the photoanode thin film, in step 1), the hydrothermal reaction is a hydrothermal reaction at 100 °C for 6 - 12 h.

[0014] The above-mentioned method of changing Fe by doping 2 O 3 Ti, Zr-Fe Photoanode Light Absorption Capacity 2 O 3 For the photoanode thin film, in step 2), the ZrO(NO 3 ) 2 ethanol solution is 1 mmol / L.

[0015] The above-mentioned method of changing Fe by doping 2 O 3 Ti, Zr-Fe Photoanode Light Absorption Capacity 2 O 3 For the photoanode thin film, in step 2), the re-hydrothermal reaction is at a temperature of 100 °C for 3 h.

[0016] The above-mentioned method of changing Fe by doping 2 O 3 Ti, Zr-Fe Photoanode Light Absorption Capacity 2 O 3 For the photoanode thin film, in step 3), the calcination is at a calcination temperature of 550 °C for 2 h.

[0017] The above-mentioned method of changing Fe by doping 2 O 3 Ti, Zr-Fe Photoanode Light Absorption Capacity 2 O 3 The photoanode thin film can be applied in photoelectrochemical water splitting for hydrogen production.

[0018] For the above application, the method is as follows: Using the above-mentioned Ti, Zr-Fe 2 O 3 photoanode thin film as the working electrode, a platinum sheet as the counter electrode, Ag / AgCl as the reference electrode, and the electrolyte is 1 M potassium hydroxide, and water is decomposed to produce hydrogen under light illumination.

[0019] The beneficial effects of the present invention are:

[0020] 1. The Ti, Zr-Fe 2 O 3 photoanode thin film provided by the present invention effectively broadens the absorption range of Fe 2 O 3 , especially significantly improving the absorption capacity for visible light.

[0021] 2. The Ti, Zr-Fe provided by the present invention 2 O 3 The preparation method of the photoanode film uses low-cost and environmentally friendly materials, and the preparation process is simple, having wide industrial application potential.

[0022] 3. The Ti, Zr-Fe provided by the present invention 2 O 3 The photoanode film significantly improves the photoelectrochemical performance. Description of the Drawings

[0023] Figure 1 The Ti, Zr-Fe 2 O 3 photoanode prepared in Example 2, and the comparative diagram of XRD of the Ti-Fe 2 O 3 film prepared in Example 1.

[0024] Figure 2 The Ti, Zr-Fe 2 O 3 photoanode prepared in Example 2, and the comparative diagram of LSV of the Ti-Fe 2 O 3 film prepared in Example 1.

[0025] Figure 3 The Ti, Zr-Fe 2 O 3 photoanode prepared in Example 2, and the comparative diagram of SEM of the Ti-Fe 2 O 3 film prepared in Example 1.

[0026] Figure 4 The Ti, Zr-Fe 2 O 3 photoanode prepared in Example 2, and the comparative diagram of UV-vis of the Ti-Fe 2 O 3 film prepared in Example 1.

[0027] Figure 5 The Ti, Zr-Fe 2 O 3 photoanode prepared in Example 2, and the hydrogen production rate diagram of water splitting of the Ti-Fe 2 O 3 film prepared in Example 1. Detailed Embodiments

[0028] Example 1 Fe 2 O 3 Photoanode Film

[0029] (I) Preparation Method

[0030] Dissolve 0.81 g of ferric chloride hexahydrate and 0.18 g of urea in 20 mL of deionized water, and add dropwise 150 μL of 5% TiCl 4 ethanol solution, and stir well to prepare a precursor solution. Place the precursor solution and the cleaned FTO conductive glass in a 100 mL hydrothermal reactor, and carry out hydrothermal reaction at 100 °C for 3 h to obtain a FeOOH photoanode film; calcine the FeOOH photoanode film at 550 °C for 2 h to obtain a Fe 2 O 3 photoanode film.

[0031] Example 2 High-performance Ti, Zr-Fe 2 O 3 photoanode

[0032] (I) Preparation method

[0033] Dissolve 0.81 g of ferric chloride hexahydrate and 0.18 g of urea in 20 mL of deionized water, and add dropwise 100 μl, 150 μl, and 200 μl of 5% TiCl 4 ethanol solution, and stir well to prepare a precursor solution. Place the precursor solution and the cleaned FTO conductive glass in a 100 mL hydrothermal reactor, and carry out hydrothermal reaction at 100 °C for 6 h, 8 h, 10 h, 12 h, and 14 h to obtain a Ti-FeOOH film.

[0034] Hydrothermally treat the Ti-FeOOH film again, and place it in a precursor solution containing 0.81 g of ferric chloride hexahydrate, 0.18 g of urea, 1 ml of 1 mmol / L ZrO(NO 3 ) 2 ethanol solution and 20 mL of deionized water. Carry out hydrothermal reaction at 100 °C for 1.5 h, 3 h, and 4 h, and calcine at 550 °C for 2 h to obtain a Ti, Zr-Fe 2 O 3 photoanode film.

[0035] Under the condition that other conditions are certain and there is only one variable, determine the optimal reaction conditions according to the photocurrent density measured by LSV. The results show that the optimal Ti doping amount is 150 μl of 5% TiCl 4 ethanol solution, the optimal hydrothermal time for the Ti-FeOOH film is 12 h, and the optimal time for the second hydrothermal Zr doping layer is 3 h.

[0036] (II) Detection

[0037] Figure 1 For the Ti, Zr-Fe 2 O 3 photoanode film prepared in Example 2, the Ti-Fe 2 O 3Comparison diagram of thin film XRD. From Figure 1 It can be seen that Ti, Zr-Fe 2 O 3 and Fe 2 O 3 diffraction peaks respectively correspond to SnO 2 (FTO)(PDF#46-1088), Fe 2 O 3 (PDF#33-0664) diffraction peaks. It is proved that doping does not change the crystal structure of Fe 2 O 3 .

[0038] Example 4 Application

[0039] Respectively, the Ti-Fe 2 O 3 , Ti, Zr-Fe 2 O 3 photoanode thin films prepared in Examples 1 and 2 were subjected to LSV, UV-vis, SEM and water splitting tests.

[0040] All electrochemical experiment tests were carried out in an electrochemical workstation (Princeton Applied Research 2273) with a three-electrode system. The sample thin film was used as the working electrode, the platinum sheet was used as the counter electrode, Ag / AgCl was used as the reference electrode, the electrolyte was 1M potassium hydroxide, a 300W xenon lamp, 100mW / cm 2 The light irradiation area of the sample was 1 cm 2 , and the water splitting test used GC-1690 to detect the hydrogen production in each period of time.

[0041] LSV test: The light source was a 300W xenon lamp (100mW / cm 2 ), the bias voltage was 1.23V vs. RHE, and the measured results were as Figure 2 shown. The results showed that the photocurrent density of the Ti, Zr-Fe 2 O 3 photoanode thin film was much larger than that of Ti-Fe 2 O 3 , indicating that the photoelectrochemical performance was improved after doping.

[0042] SEM test: The measured results were as Figure 3 shown. After the co-doping was formed by hydrothermal treatment again, the film thickness of the Ti, Zr-Fe 2 O 3 photoanode increased, and the doped layer on the surface presented a porous structure.

[0043] UV-vis test: The measured results were as Figure 4As shown, after secondary hydrothermal co-doping, the light absorption range and light absorption ability of the Ti-Fe 2 O 3 photoanode are significantly improved.

[0044] Hydrogen production test by water splitting: The light source is a 300W xenon lamp (100mW / cm 2 ), the bias voltage is 1.23V vs. RHE, and the measured results are as Figure 5 shown. After forming the Ti,Zr-Fe 2 O 3 photoanode by secondary hydrothermal co-doping, the hydrogen production rate (32.3μmol h 2 O 3 ) value of the Ti,Zr-Fe -1 cm -2 ) photoanode film is greater than that of the Ti-Fe 2 O 3 photoanode (9.1μmol h -1 cm -2 ), proving that the water oxidation driving force of Ti,Zr-Fe 2 O 3 is also improved.

Claims

1. A Ti, Zr-Fe2O3 photoanode film that changes the light absorption capacity of Fe2O3 photoanode by doping, characterized in that: The preparation method comprises the following steps: 1) dissolving iron salt and urea in deionized water, adding ethanol solution of TiCl4, and stirring to obtain a precursor solution; placing the precursor solution and FTO conductive glass in a hydrothermal reactor, growing precursor Ti-FeOOH on the conductive glass FTO through a hydrothermal reaction, and obtaining a precursor Ti-FeOOH photoanode film; 2) placing the Ti-FeOOH photoanode film in a precursor solution containing iron salt, urea and ZrO(NO3)2 ethanol solution, and performing a hydrothermal reaction again to obtain a Ti, Zr-FeOOH photoanode; 3) Calcine Ti, Zr-FeOOH under air conditions to obtain Ti, Zr-Fe2O3 photoanode film.

2. The Ti, Zr-Fe2O3 photoanode film of claim 1, wherein the light absorption capacity of the Fe2O3 photoanode is changed by doping. In step 1), the iron salt is ferric chloride hexahydrate or ferric sulfate.

3. The Ti, Zr-Fe2O3 photoanode film of claim 1, wherein the light absorption capacity of the Fe2O3 photoanode is changed by doping. In step 1), it is characterized in that the molar ratio of iron salt to urea is 1-2:

1.

4. The Ti, Zr-Fe2O3 photoanode film of claim 1, wherein the light absorption capacity of the Fe2O3 photoanode is changed by doping. In step 1), the molar ratio of TiCl4: iron salt: urea is (0.75-1.25):40:

40.

5. The Ti, Zr-Fe2O3 photoanode film of claim 1, wherein the light absorption capacity of the Fe2O3 photoanode is changed by doping. In step 1), the hydrothermal reaction is carried out at 100° C. for 6-12 hours.

6. The Ti, Zr-Fe2O3 photoanode film of claim 1, wherein the light absorption capacity of the Fe2O3 photoanode is changed by doping. In step 2), the ZrO(NO3)2 ethanol solution is 1 mmol / L.

7. The Ti, Zr-Fe2O3 photoanode film of claim 1, wherein the light absorption capacity of the Fe2O3 photoanode is changed by doping. In step 2), the hydrothermal reaction is carried out again at a temperature of 100° C. for 3 hours.

8. The Ti, Zr-Fe2O3 photoanode film of claim 1, wherein the light absorption capacity of the Fe2O3 photoanode is changed by doping. In step 3), the calcination temperature is 550° C. and the time is 2 h.

9. The Ti, Zr-Fe2O3 photoanode film described in any one of claims 1 to 8, which is capable of changing the light absorption capacity of the Fe2O3 photoanode by doping, can be used in photoelectrochemical water decomposition to produce hydrogen.

10. The use according to claim 9, characterized in that: The method is as follows: using the Ti, Zr-Fe2O3 photoanode film described in any one of claims 1 to 8 as a working electrode, a platinum sheet as a counter electrode, Ag / AgCl as a reference electrode, and an electrolyte of 1M potassium hydroxide to decompose water to produce hydrogen under light conditions.

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