Preparation and photoelectrochemical performance of nano Bi₂S₃–TiO₂ composites

Abstract

TiO 2 nanorod (NR) arrays were prepared on FTO by the simple hydrothermal synthesizing method. On this basis, a layer of Bi 2 S 3 quantum dots (QDs) was covered on the surface of TiO 2 NRs array by solvothermal method, by which the Nano Bi 2 S 3 /TiO 2 NRs composites films were obtained. The phase structure, morphologies, optical absorptions and photoelectrochemical (PEC) properties of the as-prepared materials were characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscopy (HRTEM), Ultraviolet–visible spectroscopy (UV-Vis), Photoluminescence (PL) and electrochemical workstation. The results indicate that the concentration of tetrabutyl titanate (TBT) has a great influence on the morphology of the film, with the increase of TBT content, the array of TiO 2 NRs changed from loose to tight, and the thin films were cracked when the TBT volume is up to 0.7[Formula: see text]mL; The absorption of the TiO 2 NRs array film to the visible light is enhanced significantly when sensitized with Bi 2 S 3 and the absorption wavelength is increased from 400[Formula: see text]nm to 800[Formula: see text]nm. Compared with the pure TiO 2 , the fluorescence intensity of the TiO 2 /Bi 2 S 3 NRs is weakened, and there is no obvious fluorescence diffraction peak. Under the irradiation of standard (AM1.5[Formula: see text]G 100[Formula: see text]mW/cm[Formula: see text], the photocurrent density of the composite film increased significantly. When the external bias voltage is 1.2[Formula: see text]V, the current density of the composite films is five times of that of the pure TiO 2 .