Based On Precious Metal/Bi₂WO₆,Preparation And Photo-electrocatalytic Performance Of Composites

Photoelectric catalytic technology is an important technology for converting renewable solar energy into chemical energy.It usually uses semiconductor nanomaterials as the main body of the catalyst,and plays an important role in the field of decomposing water to produce hydrogen,degrading organic pollutants and antibiotics.Due to the excellent thermodynamic and optical properties of bismuth tungstate（Bi₂WO₆）semiconductor material,and its narrow band gap of about 2.7 e V,it shows a certain collection capacity for visible light,and has been widely concerned by researchers.However,because of the short lifetime of Bi₂WO₆ photogenerated charge and poor conductivity,which has seriously hindered its practical application.In order to improve the photocatalytic activity of Bi₂WO₆ and expand its application in different fields.In this paper,through the construction of Bi₂WO₆ and noble metal or other semiconductor composite,inhibit the conbination of photogenerated electron-hole pair of Bi₂WO₆ semiconductor material interface to improve the photocatalytic activity of Bi₂WO₆;and as-obtained composite material prepared as a working electrode to evaluate their photoelectrocatalytic activity in fuel cells and pollutant degradation.Details as follows:（1）Two-dimensional（2D）Bi₂WO₆ semiconductor nanosheets were prepared by a simple hydrothermal method.Subsequently,2D Bi₂WO₆ semiconductor nanosheets were used as carriers for the deposition of precious metal platinum nanoparticles（Pt NPs）,and ultra-small size Pt（5.4nm）was deposited on Bi₂WO₆ surfaces.The as-obtained Pt-Bi₂WO₆ composite material was prepared as a working electrode,and its photoclectrocatalytic activity was evaluated by ethylene glycol oxidation.Compared with traditional electrocatalytic process,the catalytic activity of the Pt-Bi₂WO₆ electrode under visible light irradiation increased by about 4.2 times,and diaplayed higher stability.（2）At first,La₂Ti₂O₇（LTO）nanosheets were synthesized,then as-obtained LTO added the preparation procedure of Bi₂WO₆ to synthesize 2D Bi₂WO₆/LTO heterojunction,and as-prepared Bi₂WO₆/LTO as a carrier of Pt NPs.Subsequently,the Pt-Bi₂WO₆/LTO composite material used as a working electrode,and its electrocatalytic activity and stability to methanol oxidation were evaluated under visible light irradiation.Compared with traditional electrocatalytic methanol oxidation,the Pt-Bi₂WO₆/LTO working electrode shows excellent catalytic performance and stability with the aid of visible light.Therefore,Pt-Bi₂WO₆/LTO nanocomposites are feasible as catalysts in the catalytic oxidation of methanol,which provides new ideas for the development of direct methanol fuel cell.（3）A bismuth tungstate/reduced graphene oxide composite material（Bi₂WO₆/RGO）with excellent optical,electrical and thermal stability was synthesized by hydrothermal method,and used as a carrier of Pt NPs.As-prepared used Pt-Bi₂WO₆/RGO working electrode,under the dark condition,Pt-Bi₂WO₆/RGO showed better activity than Pt-Bi₂WO₆ in electrocatalytic oxidation of methanol.Under visible light irradiation,the catalytic activity and stability of Pt-Bi₂WO₆/RGO for methanol oxidation were further improved,It proved that RGO as the promoter of Bi₂WO₆ can promote the catalytic activity of Pt-Bi₂WO₆/RGO for methanol oxidation.（4）Snowflake-shaped Cu₂S nanosheets were synthesized by solvothermal method,then combined the as-obtained Cu₂S snowflakes with Bi₂WO₆ nanosheets to synthesize 2D/3D Bi₂WO₆nanosheets/Cu₂S snowflake heterojunction,and finally,2D/3D Bi₂WO₆/Cu₂S heterojunction was used as a carrier to deposit Pt NPs.The photoelectrcatalytic activity of as-prepared Pt-Bi₂WO₆/Cu₂S used as the working electrode was evaluated in methanol oxidation reaction（MOR）.Compared with the Pt-Bi₂WO₆ modified electrode,under the same conditions,Pt-Bi₂WO₆/Cu₂S modified electrode exhibited higher catalytic performance in the electrocatalytic methanol oxidation process.More importantly,compared with the traditional electrocatalytic process,visible light assist can greatly improve the electrocatalytic activity,stability and anti-toxicity of Pt-Bi₂WO₆/Cu₂S working electrode.In addition,we found that the 2D/3D Bi₂WO₆/Cu₂S heterojunction exhibited excellent photoelectrocatalytic activity in the methylene blue degradation.All results show that 2D/3D Bi₂WO₆/Cu₂S composite material has potential application prospects in photoelectrocatalytic methanol oxidation and methylene blue degradation activity.