Understanding and improving photoelectrochemical performance of Bi2O3/Bi2S3 composite

Abstract

Simple, fast synthesis methods for well-aligned semiconductors on a substrate are necessary for the practical application of photoelectrochemical (PEC) reactions. A well-defined Bi₂O₃/Bi₂S₃ composite was successfully synthesized using an ultrasonic-assisted synthetic method on a conductive substrate. During the sonochemical reaction, the Bi₂O₃ layer reacted with S²⁻ ions to form Bi₂S₃. Because no other Bi³⁺ sources were present during the synthetic process, the Bi₂O₃ layer acted as both the substrate and Bi³⁺ source for the formation of the Bi₂S₃ film. The resulting Bi₂O₃/Bi₂S₃ composite showed highly enhanced PEC activity, with a photocurrent more than twice that of other Bi₂O₃/Bi₂S₃ samples at 0.80 V (vs. RHE). This enhanced activity was attributed to the composite interface with low interfacial resistance achieved by in situ growth, which enhanced photogenerated electron transfer from the Bi₂S₃ conduction band to that of Bi₂O₃. Furthermore, the stability of the Bi₂O₃/Bi₂S₃ composite during water oxidation was examined by using substrate generation-tip collection scanning electrochemical microscopy.