Enhanced visible light photoelectrochemical performance of β-Bi2O3-TiO2/ITO thin films prepared by aqueous sol-gel

Abstract

Semiconductor heterojunction of β-Bi2O3-TiO2/ITO thin films was prepared by aqueous sol-gel and their photoelectrochemical and photoelectrocatalytic properties were evaluated on the oxidation of salicylic acid. The β-Bi2O3 sol precursor properties were characterized by DLS, SEM, and X-ray diffraction. The composition and morphology of the films were characterized by SEM-EDS. The photoelectrochemical characterization was performed by linear sweep voltammetry with chopped light irradiation and photocurrent measurements. The photoelectrocatalytic activity of the films under UV-Vis and visible light irradiation was conducted on the oxidation of salicylic acid. Results show that the films are composed of a TiO2 layer with Bi2O3 particles dispersed throughout the surface. X-ray diffraction results confirm that the Bi2O3 obtained from the sol precursor prepared corresponds to β-tetragonal phase. The linear sweep voltammetry shows that the β-Bi2O3-TiO2/ITO films have a higher photocurrent in the anodic region than TiO2/ITO films used as reference. The photoelectrocatalytic activity of the β-Bi2O3-TiO2/ITO films on the oxidation of salicylic acid under visible light irradiation was higher than TiO2/ITO films. The results show that the β-Bi2O3-TiO2/ITO films are active under visible light and can be used in photoelectrochemical cells.