Preparation And Photoelectrochemical Properties Of Cu₂O/WO₃ Semiconductor

Cuprous oxide?Cu₂O?is a p-type semiconductor material with small band gap,which is widely used in photocatalysis owing to its excellent photocatalytic properties.However,the high recombination rate of photo-generated electron-hole of Cu₂O,which leads to the low photocatalytic activity.Therefore,how to reduce Cu₂O photo-generated electron-hole recombination has been a key issue to improve its photocatalytic activity.The objective of this work is to improve the photocatalytic activity and stability of the Cu₂O by reducing the recombination rate of elctron-hole pairs and decrease the grain size of Cu₂O.In this work,Cu₂O film and Cu₂O/WO₃ composite semiconductor films have been preparated via anodic oxidation method.The effects of anodizing voltage,temperature,time,electrolyte concentration,and post annealing temperature on the morphologies and performance of the films.The microstructures and properties of Cu₂O film and Cu₂O/WO₃ composite semiconductor films are characterized by XRD,EDS,SEM,TEM,UV-vis,I-t,Mott-Schottky,and EIS.It is found that Cu₂O/WO₃ composite semiconductor films can be preparated via anodic oxidation method in either alkaline or acidic solutions.Compared with single Cu₂O film,the composite structuere of Cu₂O/WO₃ can effectively improve photocatalytic activity through the enhanced photocurrent density and carrier concentration.After post-annealing at 350?,the as-deposited Cu₂O/WO₃ films at 10 V in KOH solution change to granular microstructure,and the photocatalytic activity increase dramatically.Specifically,the photocurrent density achieves its maximum of 1.977 mA/cm²,which is 49 times of that of single Cu₂O films.After annealing at 400 ?,the Cu₂O/WO₃ composite semiconductor films achieve the maximum photocurrent density of 0.68 mA/cm²,which is 17 times of that of single Cu₂O film Compared with the semiconductor thin film of pure Cu₂O,Cu₂O/WO₃ compound semiconductor thin film increases the composite film photocurrent density and carrier concentration,improved the photocatalytic activity of Cu₂O.