Photo-electrochemical properties of Sb₂S₃/TiO₂ heterostructures integrally synthesis by hydrothermal method

TiO₂ based heterostructures exhibits better photoelectrochemical performances than TiO₂ photoanodes solely. However the fact that their synthesis necessitates more than one technique increases their cost. Finding simple and low cost methods to fabricate these heterostructures remain a challenge to many researchers. Trying to overcome this challenge, we propose, in this work, a facile and low cost strategy to sensitize TiO₂ nanorod arrays with Sb₂S₃ nanoparticules, in order to improve the visible light absorbance and the photoelectrochemical performance of the Sb₂S₃/TiO₂ related photoanodes. Such photoanodes were successfully prepared on an F: SnO₂ conductive glass by a two-step process of hydrothermal method. Scanning electron microscopy indicated that the Sb₂S₃ nanoparticles were distributed homogeneously on the surface of TiO₂ nanorods. Linear sweep voltammetry results indicated that the highest photocurrent density reached 0.97 mA cm⁻² at an applied potential of 0 V vs Ag/AgCl. This performance is attributed to the appropriate relative energy band gap positions between the Sb₂S₃ and TiO₂ in one hand and Sb₂S₃ and electrochemical potential of water oxidation on the other hand. Flat-band potential and free carrier concentration was determined by Mott–Schottky plots. Electrochemical impedance spectroscopy was employed and an equivalent circuit model is proposed.