Bi2S3-Nanowire-Sensitized BiVO4 Sheets for Enhanced Visible-Light Photoelectrochemical Activities

BiVO4 is widely used for photoelectrochemistry and photocatalytic oxygen evolution under visible-light irradiation. To extend the range of visible-light absorption and reduce the recombination rate of photoexcited electrons and holes, a BiVO4 sheet Bi2S3 nanowire heterostructure was fabricated through an easy in situ hydrothermal method. In this method, Bi2S3 nanowires were uniformly coated onto the surface of BiVO4 sheets. The heterostructure exhibits a wide visible-light absorption band ranging from 525 to 900 nm after coupling with Bi2S3 nanowires. The BiVO4 sheet Bi2S3 nanowire heterostructures were used for photoelectrochemical measurements and exhibited higher photo current intensity than those of BiVO4 sheets and BiVO4 particle Bi2S3 under visible-light irradiation. The optimized amount of Bi2S3 in the heterostructure was approximately 2.4 at. %. The remarkable enhancements in the photoelectrochemical property were attributed mainly to the solid sensitization of Bi2S3 nanowires providing a number of photoexcited electrons, shortening transport distance in BiVO4 sheets, smoothening migration along Bi2S3 nanowires, and enhancing the synergistic effect between BiVO4 and Bi2S3.