Strong Metal-Support Interaction Modulation between Pt Nanoclusters and MnO Nanosheets through Oxygen Vacancy Control to Achieve High Activities for Acidic Hydrogen Evolution.

The optimization of metal-support interactions is used to fabricate noble metal-based nanoclusters with high activity for hydrogen evolution reaction (HER) in acid media. Specifically, the oxygen-defective MnO nanosheets supported Pt nanoclusters of ≈1.71 nm in diameter (Pt/V·-MnO NSs) are synthesized through the controlled solvothermal reaction. The Pt/V·-MnO NSs show a superior activity and excellent stability for the HER in the acidic media. They only require an overpotential of 19 mV to drive -10 mA cm and show negligible activity loss at -10 and -250 mA cm for >200 and >60 h, respectively. Their Pt mass activity is 12.4 times higher than that of the Pt/C and even higher than those of many single-atom based Pt catalysts. DFT calculations show that their high HER activity arises mainly from the strong metal-support interaction between Pt and MnO. It can facilitate the charge transfer from MnO to Pt, optimizing the H adsorption on the catalyst surface and promoting the evolution of H through the Volmer-Tafel mechanism. The oxygen vacancies in the V·-MnO NSs are found to be inconducive to the high activity of the Pt/V·-MnO NSs, highlighting the great importance to reduce the vacancy levels in V·-MnO NSs.