Urchin-like Bi2S3 modified TiO2 for improved photocathodic protection of 304SS

Severe charge recombination and poor light absorbance are the limiting factors for TiO2 to access efficient photocathodic protection (PCP) towards metals. Engineering the TiO2 with Bi2S3 to form the heterojunction is proposed to overcome these limitations. Impressively, the optimal Bi2S3-12h@TiO2 photoanode coupled with 304SS displays an open circuit potential that negatively shifts to -480 mV vs Ag/AgCl, accompanied by a photoinduced current of 18.5μA/cm2. Comprehensively, characterizations discover that a tight interface between TiO2 and Bi2S3 exhibits strong electron interaction. The resulting enhanced PCP performance is attributed to extending the photoresponse range, increasing the carrier density, and engineering the type II heterojunction. This work proves and validates the effectiveness of Bi2S3@TiO2 in enhancing the PCP performance and provides the instruction to construct a high-performance photoanode.