Efficient solar water oxidation by WO3 plate arrays film decorated with CoOx electrocatalyst

We report the synthesis and photoelectrochemical characterization of CoOx oxygen evolution catalyst modified two-dimensional (2D) WO3 plate arrays photoelectrode. The 2D-WO3 plate arrays were prepared perpendicularly on the FTO substrate by hydrothermal method. The CoOx nanoparticles were deposited on the surface of WO3 plate arrays on FTO by chemical deposition process. The CoOx nanoparticles are distributed on the surface of WO3 plates with a diameter of about 20 nm. The CoOx/WO3 film shows enhanced photoelectrochemical performance than the bare WO3 film. The highest incident-photon-to-current-efficiency (IPCE) value increases from 24.9% to 49.1% when introducing CoOx. The deposited CoOx electrocatalyst on WO3 surface can transfer holes effectively through the cobalt ion valency cycle, suppress the hole's accumulation and recombination at the electrode surface, achieve the superior kinetics and consequently enhance the overall solar water oxidation efficiency.