Amorphous cobalt potassium phosphate microclusters as efficient photoelectrochemical water oxidation catalyst

A novel amorphous cobalt potassium phosphate hydrate compound (KCoPO4. H2O) is identified to be active photocatalyst for oxygen evolution reaction (OER) to facilitate hydrogen generation from water photolysis. It has been synthesized through a facile and cost-effective solution-based precipitation method using earth-abundant materials. Its highly porous structure and large surface areas are found to be responsible for the excellent electrochemical performance featuring a low OER onset at similar to 550 rnVscE and high current density in alkaline condition. Unlike traditional cobalt-based spinel oxides (Co3O4, NiCo2O4) and phosphate (Co Pi, Co(PO3)(2)) electrocatalysts, with proper energy band alignment for lightassisted water oxidation, cobalt potassium phosphate hydrate also exhibits robust visible-light response, generating a photocurrent density of 200 mu A cm(-2) at 0.7 VscE. This catalyst could thus be considered as a promising candidate to perform photoelectrochemical water splitting. (C) 2013 Elsevier B.V. All rights reserved.