Hydrogen evolution on non-metal oxide catalysts

Abstract

Water splitting to produce hydrogen gas, using renewably produced electricity (electrocatalysis) or by direct conversion of solar energy (photocatalysis), is a strategy that addresses key environmental and energy challenges. The overall water splitting reaction proceeds as two half reactions, namely the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), each of which require catalysts specifically tailored to maximize efficiency. The benchmark catalysts for the HER are noble metals. However, their expense and rarity makes them economically unfeasible for large-scale H2 production from water. Consequently, there are considerable efforts to find cheap, abundant materials that can efficiently catalyze the HER. Over the last decade, metal chalcogenides and phosphides have emerged as promising candidates for HER. In this review article, we discuss a selection of the multitude of studies and materials in these two classes of catalyst to give a flavor of the relevant developments and properties of these materials. In addition to the selection of catalyst materials, preparation and structuring are playing a strong role in enhancing HER and overcoming fundamental challenges. The role of modeling in the performance of HER catalysts is also discussed and we end with a short perspective on the key attributes of a good HER catalyst.