Efficient all p-type heterojunction photocathodes for photoelectrochemical water splitting

In this paper, Co3O4 nanostructures with different morphologies (nanoparticles (NPs), nanosheets (NSs) and nanocubes (NCs)) are directly grown on an ITO substrate using a hydrothermal method. Sb2S3 is loaded onto Co3O4 to construct a Co3O4/Sb2S3 heterojunction, which is used as an all p-type photocathode for photoelectrochemical (PEC) water splitting for the first time. The specific morphologies of Co3O4 have been discussed in detail. The improved PEC properties of the Co3O4/Sb2S3 heterojunction are characterized. Among them, the outstanding photocurrent density of the Co3O4 NC/Sb2S3 heterojunction photocathode is accessed by −1.32 mA cm−2 at −0.4 V vs. RHE. The enhanced PEC properties result from more active sites of specific crystal planes, excellent optical performance, suitable band gradient alignment and increased charge separation and charge transfer rate.