Integration of Earth-Abundant Catalysts on Si Solar Cells for Overall Solar Hydrogen Production

Abstract

Development of low-cost and earth-abundant metal catalysts, as alternative to noble metals, is a promising approach for direct hydrogen production from solar light with integrated photoelectrochemical devices. Herein, a mild electrochemical method is used to directly synthesize two earth-abundant catalysts, namely, CoP and CoSe, on planar-junction p+nn+-Si solar cells. It is observed that the CoP–Si photocathodes achieve the best performance with ≈12 h of stability, a photocurrent density of up to 38 mA cm−2 at 0 V versus the reversible hydrogen electrode (RHE), and an onset potential of 488 mV versus RHE, and one of the most efficient solar-driven hydrogen generation from earth-abundant systems to date. Overall solar water splitting is also demonstrated in a tandem device configuration with a top TiO2 nanorod arrays photoanode achieving more than 5 h continuous hydrogen production. These results demonstrate the feasibility of using low-cost earth-abundant materials and the established Si solar cells technology for direct water splitting powered from sunlight.