Ga-Doped AgInS2 Modified with Co–Pi Co–catalyst for Efficient Photoelectrochemical Water Splitting

In this work, AgInS2 photoelectrodes doped with Ga element and deposited Co–Pi co–catalyst have been prepared on FTO substrates by hydrothermal and electrochemical deposition methods. In photoelectrochemical (PEC) measurements, the photocurrent density of AgInS2/Ga5%/Co–Pi photoelectrodes (2.18 mA/cm2 at 1.2 V vs. RHE) is about 3.25 times higher than that of pure AgInS2 photoelectrodes (0.67 mA/cm2 at 1.2 V vs. RHE). The enhanced PEC performance could be ascribed to the improved light absorption by doping Ga element and fast charge separation by depositing Co–Pi co–catalyst. This work highlights that doping appropriate metal element and loading co-catalyst to synergistically modify photoelectrodes are practicable approach for PEC water splitting.