Co-Mo-Se ternary chalcogenide thin film coated p-Si photocathode for efficient solar hydrogen production

Abstract

Photoelectrochemical (PEC) water splitting holds a great promise for clean and sustainable hydrogen production. In this study, the PEC performance of Co-Mo-Se ternary chalcogenide thin film coated Si photocathodes is investigated. The Co-Mo-Se films with various Co/Mo atomic ratios were prepared by thermal selenization of sputter deposited Co-Mo alloy films. Among the photocathodes, the Co-Mo-Se (3:10)/p-Si surpasses the PEC performance of the MoSe2/p-Si with an onset potential of +124 mV vs. reversible hydrogen electrode (RHE), a photocurrent density of -22.68 mA/cm(2) at zero overpotential and good stability over 6 h period of test. The superior performance of the Co-Mo-Se (3:10)/p-Si is ascribed to the high catalytic activity of the film in hydrogen evolution reaction (HER) and efficient collection of photogenerated charge carriers. Such ternary chalcogenide thin films offer exciting opportunities for many applications in which the physicochemical properties can be tuned by changing the relative amount of the solute atoms.