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

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.