The scalable and sustainable production of hydrogen fuel through water splitting demands efficient and robust Earth-abundant catalysts for the hydrogen evolution reaction (HER). Building on promising metal compounds with high HER catalytic activity, such as pyrite structure cobalt disulphide (CoS₂), and substituting non-metal elements to tune the hydrogen adsorption free energy could lead to further improvements in catalytic activity. Here we present a combined theoretical and experimental study to establish ternary pyrite-type cobalt phosphosulphide (CoPS) as a high-performance Earth-abundant catalyst for electrochemical and photoelectrochemical hydrogen production. Nanostructured CoPS electrodes achieved a geometrical catalytic current density of 10 mA cm^-2;at overpotentials as low as 48 mV, with outstanding long-term operational stability. Integrated photocathodes of CoPS on n⁺–p–p⁺;silicon micropyramids achieved photocurrents up to 35 mA cm^-2;at 0 V versus the reversible hydrogen electrode (RHE), onset photovoltages as high as 450 mV versus RHE, and the most efficient solar-driven hydrogen generation from Earth-abundant systems.

Nature Materials (2015) doi:10.1038/nmat4410
Received 05 May 2015 Accepted 30 July 2015 Published online 14 September 2015

http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat4410.html