ZnO/In2S3/Co–Pi ternary composite photoanodes for enhanced photoelectrochemical properties

The photoelectrochemical (PEC) water splitting properties can be enhanced by broadening the light absorption region and improving the separation of photogenerated carriers. In this paper, a novel ZnO/In2S3/Co–Pi ternary composite photoanode system is provided, by building the ZnO/In2S3 heterojunction to broaden the light absorption region and improve the separation and transfer of photogenerated electron–hole pairs in bulk, and by using the Co–Pi cocatalyst to increase the separation of photogenerated electron–hole pairs between the ZnO/In2S3 heterojunction surface and electrolyte. This ternary composite photoanode system exhibits a negative shifted onset potential and a higher photocurrent density of about 2.4 mA/cm2 at 1.23 V (vs. RHE), which is 3 and 2.18 times compared with bare ZnO nanorod and ZnO/In2S3 heterojunction, respectively. The results show that the ZnO/In2S3/Co–Pi ternary composite photoanode has an excellent potential application for PEC water splitting.