Fibrous silica bismuth sulfide: An advanced material towards promising photoelectrochemical water-splitting

Abstract

The emission of greenhouse gaseous to the atmosphere as a consequence of the utilization of fossil fuels has significantly contributed to global warming and sudden climax change which aroused a lot of concerns. This occurrence has indirectly spurred interest in hydrogen energy as a future alternative energy due to its environmentally friendly, high efficiency and long-term energy storage. Photoelectrochemical (PEC) water-splitting is a top-notch approach that can efficiently produce hydrogen. Moreover, semiconductor materials like bismuth sulfide have often been used as photoanode material in the PEC water-splitting study due to their narrow bandgap, high optical absorption coefficient, appropriate band alignment and low toxicity. Yet, Bi2S3 photoanode suffers from the rapid recombination of charge carriers which ultimately leads to sluggish water oxidation kinetics and poor charge transfer. Interestingly, the fabrication of fibrous silica bismuth sulfide (FSBS) not only demonstrated a low bandgap energy level but also effectively separated the photoproduced charges. In addition, the FSBS photoanode also showed a photocurrent density of 47.9 mA/cm2 at 1.23 VRHE which is 1.78 times greater than the commercial BS photoanode (26.9 mA/cm2). These findings indirectly exposed the potential of FSBS photoanode towards a sustainable PEC water-splitting application.