Hydrothermally obtained type-Ⅱ heterojunction nanostructures of In2S3 / TiO2 for remarkably enhanced photoelectrochemical water splitting

Despite the tremendous attempts to improve the solar-to-hydrogen conversion efficiency of TiO2 based photoelectrochemical photoanode, further progress is still needed to utilize the TiO2 as the promising photoanode materials. Herein, a highly enhanced photoanode composed of the nanostructured In2S3/TiO2 is synthesized. The photocurrent density approximately 3.5 times (2.74 mA cm−2) as high as the pristine TiO2 was obtained due to the improved carrier concentration and fast charge separation. The incident photon-to-current efficiency shows a 65.8 % while pristine TiO2 nanorods shows only 24.7 % of efficiency. Further studies on the carrier lifetime and band position were performed and clarify the generation of type-Ⅱ heterojunction between the In2S3 nanoparticles and TiO2 nanorod arrays. This study proposes the methodologies and the theoretical evidence for achieving significant improvements in the TiO2 based photoanode. Moreover, this study's all-solution-based process provides the facile and scalable method for the highly enhanced photoelectrode and allows environmentally friendly production.