Computational Criteria for Hydrogen Evolution Activity on Ligand-protected Au25-based Nanoclusters

The hydrogen evolution reaction (HER) is a critical reaction in addressing climate change, however, it requires catalysts to be generated on an industrial scale. Nanomaterials offer several advantages over conventional HER catalysts, notably the possibility of atomic precision in tailoring the intrinsic activity. Ligand-protected metal clusters, such as the thiolate-protected MAu24SR18 (M = Au, Cu, Pd), are of particular interest as not only are they electrocatalytically active towards HER, but the charge state and composition can be precisely tuned. Here, we present a comprehensive computational study examining how the charge state and dopants affect the catalytic activity of [MAu24}SCH3)18}]^q towards the Volmer step of the HER. According to the Sabatier principle, H adsorption energy should be nearly thermoneutral for an ideal catalyst. Our results show that adsorption energies alone are an insufficient criterion to identify a promising catalytic material; kinetic barriers and experimentally relevant redox potentials should also be considered. Notably, this work explains the relative activity of MAu24SR18 (M = Au, Cu, Pd) clusters reported by Kumar et al., (Nanoscale 2020, 12, 9969). Our results validate a more thorough computational approach that includes charge and potential to understand and screen electrocatalytically active nanoclusters.