Rationally designed metal nanocluster for electrocatalytic hydrogen production from water

The highly evolved hydrogenase enzymes efficiently catalyze the hydrogen evolution reaction (HER) from water. Detailed structural studies of these enzymes have triggered many research efforts to synthesize their structural mimics based on metal complexes. However, the hydrogen production rates catalyzed by these molecular complexes are still too low to be technologically viable. Here, we report that a tailored PtAu₂₄ nanocluster containing proton relays can efficiently catalyze the HER from water. We compared the electrocatalytic HER activities of Au₂₅ nanoclusters protected with three different ligands, namely, 1-hexanethiolate, 3-mercaptopropionic acid and 3-mercapto-1-propanesulfonic acid, and found that the electrocatalytic activity is closely related with the proton-relaying abilities of the ligands. The core-engineered PtAu₂₄ protected with efficient proton-relaying ligands exhibits unprecedented catalytic activity with a turnover frequency of 127 per second from water at a moderate overpotential of 0.7 V, greatly exceeding the performance of the best molecular catalyst. The atomically precise metal nanoclusters provide a platform for the design and optimization of finely tailored catalysts.