Facile fabrication of BiVO4/Bi2S3/NiCoO2 for significant photoelectrochemical water splitting

Abstract For photoelectrochemical (PEC) water splitting, BiVO4 is the most efficient light-absorber metal oxide; nevertheless, significant charge recombination and low water oxidation kinetics have been restricted its effectiveness. Therefore the idea of creating heterojunction by using metal sulfide followed by the decoration of catalyst were employed to obtain the ideal water splitting performance of the photoelectrode. In this study simple and unique strategy is developed to fabricate BiVO4/Bi2S3/NiCoO2 photoelectrode through facile and scalable solution route. Structural, morphological and optical analysis shows the stepwise fabrication of Bi2S3 and NiCoO2 upon BiVO4. BiVO4/Bi2S3/NiCoO2 composite demonstrates 5.5 times higher photocurrent density than bare BiVO4 with cathodic shift of 220 mV and greatly stable in 0.5 M Na2SO4 electrolyte. Photoelectrochemical studies involving (i) estimation of flat band position, (ii) charge transfer resistance from impedance studies (iii) prediction of band alignment and (iv) significant increase in the injection efficiency and separation efficiency together signifies the importance of the NiCoO2 and Bi2S3 in the BiVO4/Bi2S3/NiCoO2 photoanode that emphasize superb PEC water splitting performance.