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CN-122010423-A - BiPO (BiPO)4/BiVO4Array structure photo-anode, preparation method and application thereof

CN122010423ACN 122010423 ACN122010423 ACN 122010423ACN-122010423-A

Abstract

The invention provides a photo-anode with a BiPO 4 /BiVO 4 array structure, a preparation method and application thereof, wherein the photo-anode with the BiPO 4 /BiVO 4 array structure is prepared in situ by an electrodeposition-calcination-photoelectrochemical activation three-step method, a KHCO 3 solution is used as a working electrode, hydrogen peroxide is directionally generated through a double-electron water oxidation reaction under simulated sunlight irradiation, and the unique photoelectrochemical self-sacrifice reconstruction in-situ growth mechanism of the photo-anode with the BiPO 4 /BiVO 4 array structure solves the problem of poor interfacial binding force, realizes the dual functions of passivation of surface defects and selective regulation and control of catalysis, has green color temperature and high controllability of the preparation process, and remarkably improves the yield of photoelectrocatalytic synthesis H 2 O 2 .

Inventors

  • CHEN HANG
  • HE QING
  • PENG WENLIANG
  • Lai Boyin
  • XU SHURUI
  • ZHONG GUOYU

Assignees

  • 东莞理工学院

Dates

Publication Date
20260512
Application Date
20260318

Claims (10)

  1. 1. The photo-anode with the BiPO 4 /BiVO 4 array structure is characterized in that the photo-anode with the BiPO 4 /BiVO 4 array structure is prepared in situ by an electrodeposition-calcination-photoelectrochemical activation three-step method, wherein BiVO 4 in the photo-anode is of a monoclinic scheelite type crystal structure, biPO 4 is of a hexagonal phase crystal structure, and uniformly grows on the surface of a BiVO 4 array in a nano-sheet mode to form an array structure grading heterojunction.
  2. 2. The photo-anode with the BiPO 4 /BiVO 4 array structure according to claim 1, wherein the model number of BiVO 4 is JCPDS 14-0688, the photo-anode is in a porous worm-shaped array morphology, the model number of BiPO 4 is JCPDS 00-015-0766, the photo-anode is in a sheet structure, and the mass fraction of P element is 1.0% -2.0%.
  3. 3. The method for preparing the photo-anode with the BiPO 4 /BiVO 4 array structure as claimed in any one of claims 1 to 2, which is characterized by comprising the following steps: Step S1, preprocessing a conductive substrate; Step S2, preparing a BiVO 4 array film through electrodeposition, and then converting the BiVO 4 array film into a BiVO 4 array through dripping a vanadium source, calcining and alkali washing; And S3, growing a BiPO 4 layer on the surface of the BiVO 4 array in situ by a photoelectrochemical activation method to prepare the BiPO 4 /BiVO 4 array structured photo-anode.
  4. 4. The method for preparing a photo-anode with a BiPO 4 /BiVO 4 array structure according to claim 3, wherein the specific steps in the step S1 are as follows: S11, selecting fluorine-doped tin dioxide conductive glass or indium tin oxide transparent conductive film glass as a substrate, and cutting the substrate into the specification of 1-3 cm multiplied by 1-3 cm; s12, sequentially and respectively carrying out ultrasonic cleaning on the cut substrate by deionized water, acetone, isopropanol and ethanol for 5-20 min each time; and S13, after the cleaning is finished, placing the substrate in a vacuum environment at 60 ℃ for drying for 30min, taking out and sealing for standby.
  5. 5. The method for preparing the BiPO 4 /BiVO 4 array structure photo-anode according to claim 3, wherein the step S2 is to construct a three-electrode system before electrodepositing to prepare the BiVO 4 array film, and specifically comprises the steps of taking a pretreated conductive substrate as a working electrode, taking Pt wires as a counter electrode and taking Ag/AgCl electrodes as reference electrodes.
  6. 6. The method for preparing a photo-anode with a BiPO 4 /BiVO 4 array structure according to claim 3, wherein the specific steps in the step S2 are as follows: S21, preparing a mixed electrolyte, namely dissolving 2-5 mmol/L bismuth nitrate pentahydrate, 10-30 mmol/L potassium iodide and 3-6 mmol/L p-benzoquinone into deionized water, regulating the pH of a system to 1.5-2.3 by using 0.5-2M nitric acid, and performing ultrasonic dispersion for 15min; s22, performing electrodeposition operation, namely performing electrodeposition for 60-160S under the potential of minus 0.1 to minus 0.2Vvs. Ag/AgCl, and forming a BiOI array film on the surface of the substrate; s23, dripping and calcining a vanadium source, namely uniformly dripping a dimethyl sulfoxide solution of 0.1-0.5 mol/L vanadyl acetylacetonate on the surface of the BiOI array film with the dosage of 50-100 mu L/cm < 2 >; S24, post-treatment purification, namely naturally cooling after calcination, placing the substrate in a NaOH aqueous solution with the concentration of 0.1-1 mol/L, stirring and cleaning for 20-35 min, repeatedly flushing with deionized water until the washing liquid is neutral, and vacuum drying to obtain the BiVO 4 array.
  7. 7. The method for preparing a photo-anode with a BiPO 4 /BiVO 4 array structure according to claim 3, wherein the specific steps in the step S3 are as follows: s31, preparing a PBA buffer solution, namely preparing a 0.1-0.5M phosphate-borate-acetate buffer solution; s32, constructing a photoelectrochemical system, namely placing three electrodes in the PBA buffer solution by taking a BiVO 4 array as a working electrode, a Pt electrode as a counter electrode and Ag/AgCl as a reference electrode; S33, photoelectrochemistry activation treatment, namely starting AM1.5G simulated sunlight, applying 0.8-1.5Vvs. RHE constant bias voltage to a working electrode, and continuously performing activation treatment for 30-180 min; s34, after finishing the reaction, taking out the working electrode, flushing the surface with 50mL of deionized water for three times, and drying for 2 hours in a 60 ℃ vacuum environment to finally obtain the photo-anode with the BiPO 4 /BiVO 4 array structure.
  8. 8. The method for preparing a photo-anode with a BiPO 4 /BiVO 4 array structure according to claim 7, wherein the buffer solution in the step S31 is prepared by mixing KH 2 PO 4 、H 3 BO 3 with an equal concentration and an equal volume with acetic acid solution, and adjusting the pH of the solution to 3.0-8.0 by dropwise adding acetic acid or KOH.
  9. 9. The method for preparing the photo-anode with the BiPO 4 /BiVO 4 array structure according to claim 7, wherein the light intensity of sunlight in S33 is 50-150 mW/cm2.
  10. 10. The application of the photo-anode with the BiPO 4 /BiVO 4 array structure as claimed in any one of claims 1 to 9, which is characterized in that the photo-anode with the BiPO 4 /BiVO 4 array structure is used as a working electrode, KHCO 3 solution is used as electrolyte, and hydrogen peroxide is directionally generated through double-electron water oxidation reaction under the irradiation of simulated sunlight.

Description

BiPO 4/BiVO4 array structure photo-anode, preparation method and application thereof Technical Field The invention belongs to the technical field of photo-electrolysis water materials, and particularly relates to a photo-anode with a BiPO 4/BiVO4 array structure, a preparation method and application thereof. Background Hydrogen peroxide (H 2O2) is used as a green and efficient chemical oxidant, medical disinfectant and fuel cell fuel, only generates oxygen and water after reaction, has no secondary pollution, and has irreplaceable application value in the fields of environmental protection, medical and health, fine chemical synthesis, energy sources and the like. The traditional H 2O2 preparation is mainly carried out by an anthraquinone method, the process steps are complicated, an organic solvent and a noble metal Pd catalyst are required to be used, the process is carried out under the conditions of high temperature and high pressure, the energy consumption is huge, a large amount of organic waste liquid is generated to cause environmental pollution, and meanwhile, the storage and long-distance transportation of the product have obvious potential safety hazards. To solve the above problems, the photoelectrocatalysis technology has been the focus of research in the field of H 2O2 green synthesis by virtue of the unique advantage of "photo-electro-chemical" synergistic conversion. Among the many semiconductor photoelectrocatalysis materials, biVO 4 is a core photoanode candidate material for synthesizing H 2O2 by photoelectrocatalysis of water oxidation. However, the pure-phase BiVO 4 has inherent performance bottlenecks that firstly, electron conductivity is poor, photo-generated carriers are slow in migration rate, reaction kinetics is limited, secondly, electron-hole pair recombination probability is high, a large number of carriers are annihilated without participating in surface reaction, actual photocurrent density is far lower than a theoretical value, and synthesis efficiency and selectivity of H 2O2 are severely restricted. At present, a plurality of modification strategies such as element doping, heterojunction construction, cocatalyst loading, morphology regulation and control, surface passivation and the like are adopted. For example, patent CN119571382B discloses a CoSnO 3/BiVO4 photoanode, a preparation method and an application thereof in preparing hydrogen peroxide, preparing CoSn (OH) 6 powder by a coprecipitation method and a hydrothermal method, and preparing a composite photoanode on an FTO substrate by combining an electrodeposition method and a spin coating method, wherein perovskite CoSnO 3 is adopted as a composite component, but the preparation process is required to synthesize CoSn (OH) 6 powder separately, and then the process is relatively complex by multi-step coating and calcination, which is not beneficial to cost control and mass production. Patent CN105749942A discloses a balsam pear-shaped BiVO 4/BiPO4 heterojunction photocatalytic material, a preparation method and application thereof, and adopts a coprecipitation hydrothermal method to synthesize the heterojunction material in one step, wherein the material shows higher activity in the aspect of photocatalytic degradation of organic pollutants, and the preparation method is a powdery catalyst, and has limited charge transmission efficiency and practical application suitability. Patent CN107098429A discloses a BiVO 4/BiPO4 composite material, a preparation method and application thereof, wherein the composite material of BiVO 4 nano particles attached to the surface of a BiPO 4 nano rod is prepared by an in-situ acid radical ion exchange method, the method is simple in process, the obtained material has universality on degradation of organic pollutants, and the composite material is in a powder form and is difficult to be directly used as a photo-anode for a photoelectrocatalysis system. Therefore, the development of the BiVO 4 modification technology with low cost, simple process, high charge transmission efficiency and strong structural stability is of great significance for the photoelectrocatalysis system. Disclosure of Invention Aiming at the problems in the prior art, the invention utilizes the excellent photocatalysis performance of BiPO 4, has good matching performance with the energy band structure of BiVO 4, and can promote the directional transmission of photo-generated carriers by means of a built-in electric field after the BiPO 4 and the BiVO 4 are combined to form a heterojunction, thereby effectively inhibiting the characteristic of electron-hole combination and further realizing excellent selectivity and yield of H 2O2 synthesis. Meanwhile, the BiPO 4 has stronger adsorption capacity to HCO 3-, can enrich the local HCO 3- concentration of an electrode/electrolyte interface, provides sufficient reaction species for a double-electron water oxidation path, has weaker adsorption effect to H 2O2 by the BiPO 4,