Photoelectrochemical Water Splitting of CuInS2 Photocathode Collaborative Modified with Separated Catalysts Based on Efficient Photogenerated Electron–Hole Separation

Accelerating the separation and transfer of photogenerated carriers of a photoelectrode is vital to achieve a substantial performance increase for the photoelectrochemical (PEC) water splitting. In this paper, a CuInS 2 photocathode collaborative modified with separated cocatalyst layers including top Pt layer and bottom FeOOH layer is first fabricated to ameliorate PEC water splitting. The FeOOH layer can utilize holes from the CuInS 2 layer and then transfer holes through the conductive glass and wire to the counter electrode. The Pt layer can collect and transfer electrons from the CuInS 2 layer to the surface for water reduction. The collaborative FeOOH and Pt ameliorate effectively the hole and electron separation so as to improve PEC performances. An improved photocurrent density of ITO/FeOOH/CuInS 2 /Pt photocathode reaches −6.79 mA·cm –2 at −0.4 V vs RHE. Moreover, this study will be instructive for the design of efficient photocathode used in photoelectrochemical water splitting.