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CN-116532134-B - Z-schema type composite photocatalytic material and preparation method thereof

CN116532134BCN 116532134 BCN116532134 BCN 116532134BCN-116532134-B

Abstract

The invention discloses a Z-Scheme type composite photocatalytic material and a preparation method thereof, and particularly a series of Cu 2 O/rGO/BiOBr composite materials are successfully prepared by adopting a two-step method, and the dosage of Cu 2 O in the composite materials is optimized through the photoreduction of Cr (VI) under the irradiation of visible light. Electrons and charges between Cu 2 O, rGO and BiOBr are transferred and separated, so that the light energy utilization rate and the photo-generated electron-hole separation efficiency are improved, and the photocatalysis efficiency is further improved.

Inventors

  • MA JIAN
  • WANG CHONGTAI
  • Liang Congjie
  • HUA YINGJIE

Assignees

  • 海南师范大学

Dates

Publication Date
20260505
Application Date
20220125

Claims (8)

  1. 1. The Z-schema type composite photocatalytic material is applied to Cr (VI) photoreduction and is characterized in that Cu 2 O particles are adhered to the surface of rGO and combined with BiOBr microspheres to form the Z-schema type composite photocatalytic material, namely Cu 2 O/rGO/BiOBr, the particle size of Cu 2 O is 80-100nm, the mass ratio of Cu 2 O in the composite material is 20%, the conduction band potential and the valence band potential of Cu 2 O are higher than the corresponding potential of BiOBr, and a heterojunction is formed at the interface between Cu 2 O, rGO and BiOBr.
  2. 2. A method for preparing a Z-schema type composite photocatalytic material for Cr (VI) photoreduction according to claim 1, characterized in that the Cu 2 O/rGO/bitbr composite material is prepared by an in-situ growth method.
  3. 3. The method of manufacturing according to claim 2, comprising the steps of: (1) Preparing BiOBr, namely dissolving KBr and a certain amount of PVP in distilled water, stirring uniformly to obtain a solution A, adding Bi (NO 3 ) 3 into ultrapure water, performing ultrasonic treatment to obtain a solution B, adding the solution A into the solution B, adjusting the pH value to about 6, transferring the mixed solution into an autoclave to react at a certain temperature, cooling to room temperature, collecting a product, washing with ultrapure water and ethanol for a plurality of times, and drying; (2) Cu 2 O/rGO/BiOBr is prepared through dispersing BiOBr and rGO in deionized water, ultrasonic treatment, dissolving Cu (AC) 2 •H 2 O, CTAB and EDTA in the mixture, adding NaOH solution and ascorbic acid solution, stirring, centrifugally separating to obtain precipitate, washing with deionized water and alcohol, and vacuum drying.
  4. 4. The method according to claim 3, wherein the molar ratio of KBr to Bi (NO 3 ) 3 ) in the step (1) is 1-1.1:1-1.1.
  5. 5. The preparation method according to claim 3, wherein the reaction temperature in the step (1) is 90-110 ℃, the reaction time is 1-2 hours, the drying temperature is 40-50 ℃, and the drying time is 10-15 hours.
  6. 6. The method according to claim 3, wherein the mass ratio of Cu (AC) 2 •H 2 O, CTAB to EDTA in the step (2) is 2-4:4-6:4-6.
  7. 7. The method according to claim 3, wherein the concentration of the NaOH solution in the step (2) is 0.4-0.5 mol/L, the concentration of the ascorbic acid solution is 0.2-0.4 mol/L, and the volume ratio of the NaOH solution to the ascorbic acid solution is 1-1.1:1-1.1.
  8. 8. The method according to claim 3, wherein the drying temperature in the step (2) is 60 to 70 ℃ and the drying time is 10 to 12 hours.

Description

Z-schema type composite photocatalytic material and preparation method thereof Technical Field The invention belongs to the technical field of photocatalysis, and particularly relates to a Z-schema type composite photocatalytic material and a preparation method thereof. Background With the development of industrialization, water resources are polluted to different degrees. Hexavalent chromium (Cr (VI)) is a common contaminant in wastewater and is harmful to both humans and wild animals. At present, methods for removing Cr (VI) include adsorption, chemical reduction, precipitation, and photocatalytic methods. Wherein, the Cr (VI) can not be thoroughly removed by adsorption, and the chemical reduction needs to be carried out in an acidic solution under severe conditions. Thus, photocatalysis is considered to be a simple and gentle method. In this technique, the band structure of the semiconductor plays a critical role in the photocatalytic process. Cu 2 O is a low-cost visible light response semiconductor, has proper CB potential and is an ideal candidate material for photoreduction of Cr (VI). However, the use of Cu 2 O is greatly limited by its photo-etching, where Cu + is easily oxidized by photo-generated holes. To overcome this problem, many approaches have been explored, including adding sacrificial agents, building nanostructures, coupling to non-metallic semiconductors. The research shows that BiOBr is used as one of BiOX compounds, the CB edge of the BiOBr is positioned between the CB and VB potentials of Cu 2 O, and the BiOBr can be combined with Cu 2 O to form a Z-type heterojunction photocatalyst. In such a heterojunction, photoelectrons may be transferred from CB of the BiOBr to VB of Cu 2 O, thereby increasing the reducing power of Cu 2 O, while the potential of CB is more negative. In addition, the composite material can effectively divide the photo-generated carrier and inhibit the photo-corrosion of Cu 2 O. Meanwhile, the reduced graphene oxide (rGO) has more adsorption sites and conjugated pi structures, so that the interaction between rGO and a semiconductor can be increased, and the reduced graphene oxide is superior to the most commonly used noble metal. Therefore, the invention develops a Z-schema type composite photocatalytic material based on a great deal of research and development, and aims to improve the photocatalytic efficiency of the material. Disclosure of Invention In order to overcome the defects in the prior art, the invention aims to provide a Z-Scheme type composite photocatalytic material and a preparation method thereof. The technical scheme for solving the technical problems is as follows: the first aspect of the invention provides a Z-schema type composite photocatalytic material, which is characterized in that Cu 2 O particles are adhered to the surface of rGO and combined with BiOBr microspheres to form the Z-schema type composite photocatalytic material, namely Cu 2 O/rGO/BiOBr; Further, both the conduction band and valence band potentials of Cu 2 O are higher than the corresponding potentials of BiOBr; Further, a heterojunction is formed at the interface between Cu 2 O, rGO and bitbr. The second aspect of the invention provides a preparation method of a Z-Scheme type composite photocatalytic material, which is characterized in that the Cu 2 O/rGO/BiOBr composite material is prepared by an in-situ growth method; further, the method comprises the following steps: (1) Preparing BiOBr by dissolving KBr and PVP in distilled water, stirring to obtain solution A, adding Bi (NO 3)3 into ultrapure water, performing ultrasonic treatment to obtain solution B, adding solution A into solution B, adjusting pH to about 6, transferring the mixed solution into an autoclave, reacting at a certain temperature, cooling to room temperature, collecting the product, washing with ultrapure water and ethanol for several times, and drying; (2) Cu 2 O/rGO/BiOBr is prepared by dispersing a certain amount of BiOBr and rGO in deionized water, performing ultrasonic treatment, dissolving Cu (AC) 2•H2 O, CTAB and EDTA in the mixture, adding NaOH solution and ascorbic acid solution, stirring the obtained mixture, centrifugally separating to precipitate, washing the deionized water and ethanol, and vacuum drying to obtain a target product; Further, in the step (1), KBr and Bi (molar ratio of NO 3)3 is 1-1.1:1-1.1, preferably 1:1; further, in the step (1), the reaction temperature is 90-110 ℃, preferably 100 ℃, the reaction time is 1-2 hours, preferably 1 hour, the drying temperature is 40-50 ℃, preferably 40 ℃, and the drying time is 10-15 hours, preferably 12 hours; further, in the step (2), the mass ratio of Cu (AC) 2•H2 O, CTAB to EDTA is 2-4:4-6:4-6, preferably 3:5:5; Further, in the step (2), the concentration of the NaOH solution is 0.4-0.5 mol/L, preferably 0.45mol/L, the concentration of the ascorbic acid solution is 0.2-0.4 mol/L, preferably 0.3mol/L, and the volume ratio of the NaOH solutio