Cooperation effect of heterojunction and co-catalyst in BiVO4/Bi2S3/NiOOH photoanode for improving photoelectrochemical performances

Abstract

The separation and transport of photogenerated electron–hole pairs as well as wider light absorption and surface reaction kinetics are the main limitations in photoelectrochemical water splitting. Based on these requirements for improving photoelectrochemical water splitting, a novel ternary BiVO₄/Bi₂S₃/NiOOH photoanode was successfully fabricated in this study. In this prepared photoelectrode, Bi₂S₃ serves as a light absorber for wider solar spectra harvesting, so as to affect both the efficient separation and transfer of electron–hole pairs. NiOOH acts as a water oxidation co-catalyst for the function of accelerating the surface water oxidation reaction. This completed triple BiVO₄/Bi₂S₃/NiOOH photoanode manifests the much enhanced photoelectrochemical activity with a photocurrent density of 0.91 mA cm⁻² measured at 1.23 V vs. RHE, indicating 1.8-fold and 3.0-fold improvement in photocurrent density compared with that of the BiVO₄/Bi₂S₃ heterojunction and the pristine BiVO₄, respectively. Furthermore, these results also prove that the cooperation effect between the heterojunction and co-catalyst can enhance the photoelectrochemical activity effectively and may have a great potential application in other high efficient PEC water splitting devices.