TiO2/Bi2S3 core–shell nanowire arrays for photoelectrochemical hydrogen generation

Abstract

A facile and effective procedure for the synthesis of quasi-vertically aligned TiO₂/Bi₂S₃ core–shell nanowire arrays (NWAs) is reported. The nontoxic and earth abundant Bi₂S₃ was assembled onto the hydrothermal pre-grown TiO₂ NWAs via a successive ionic layer adsorption and reaction (SILAR) method. The morphologies, microstructures, and optical properties of the pristine TiO₂ and composite TiO₂/Bi₂S₃ with different SILAR circles were characterized in detail. For photoelectrochemical (PEC) measurements, the TiO₂/Bi₂S₃ core–shell NWAs exhibited not only an enhanced photocurrent density (2.8 times higher than that of pristine TiO₂), but also a negatively shifted onset potential from 0.067 to −0.072 V vs. RHE, as compared to the TiO₂. This better PEC performance results from the broadened light absorption and the improved charge carrier separation efficiency. Our results provide a green photoelectrode for PEC hydrogen generation.