Pt-O bond as an active site superior to Pt in hydrogen evolution reaction.

The oxidized platinum (Pt) can exhibit better electrocatalytic activity than metallic Pt in the hydrogen evolution reaction (HER), which has aroused great interest in exploring the role of oxygen in Pt-based catalysts. Herein, we select two structurally well-defined polyoxometalates Na[HPtWO] (PtWO) and NaK[Pt(WO)] (Pt(WO)) as the platinum oxide model to investigate the HER performance. Electrocatalytic experiments show the mass activities of PtWO/C and Pt(WO)/C are 20.175 A mg and 10.976 A mg at 77 mV, respectively, which are better than that of commercial 20% Pt/C (0.398 A mg). The in situ synchrotron radiation experiments and DFT calculations suggest that the elongated Pt-O bond acts as the active site during the HER process, which can accelerate the coupling of proton and electron and the rapid release of H. This work complements the knowledge boundary of Pt-based electrocatalytic HER, and suggests another way to update the state-of-the-art electrocatalyst.