Si-Ti interaction in unique morphology of fibrous silica titania photoanode for enhanced photoelectrochemical water splitting

Abstract

Extensive efforts toward titania (TiO2) modification have been developed in order to overcome the shortcomings as an efficient photoanode for photoelectrochemical (PEC) water splitting. Herein, a unique morphology possessed fibrous silica titania (FST) fabricated by microemulsion method was used for the first time as a photoanode. The FST was characterized by XRD, Raman, N2 adsorption–desorption, FESEM, TEM, FTIR, XPS, UV–vis/DRS, and PL. The results confirmed the creation of a bicontinuous concentric lamellar structure of FST with a high surface area. The inclusions of Ti in the silica matrix induced the Si-Ti interaction and narrowed the band gap. The FST photoanode exhibited a superior photocurrent density of 13.79 mA/cm2 with 16.9 % solar-to-hydrogen (STH) efficiency, which is 2.5 times higher compared to commercial TiO2 which performed at 5.51 mA/cm2 with 6.8 % STH. Significantly, the conduction band of FST lies closer to the reduction potential of hydrogen compared to TiO2, leading to the fast charge transfer and allowing spontaneous production of H2. The fabrication of FST provided new insight into developing high-performance photoanode for enhanced PEC water splitting.