Amorphous/Crystalline ZrO with Oxygen Vacancies Anchored Nano-Ru Enhance Reverse Hydrogen Spillover in Alkaline Hydrogen Evolution.

Hydrogen spillover-based binary (HSBB) system has attracted significant attention in alkaline hydrogen evolution reaction (HER). Accelerating hydrogen spillover in the HSBB system is crucial for the HER activity. Herein, a highly efficient HSBB system is developed by anchoring nano-Ru on oxygen vacancy (Vo) rich amorphous/crystal ZrO. Theoretical and experimental results reveal that the water molecules dissociate on the Vo of ZrO into protons, which then couple with electrons to form H, and the produced H are spilled over to the nano-Ru to evolve H. The amorphous regions enhance the adsorption and desorption rates of hydrogen while exposing a greater number of active sites; meanwhile, the Vo significantly reduce the work function of ZrO, facilitates electron transfer from ZrO to Ru, and thereby accelerates hydrogen spillover. As a result, the Ru/ac-ZrO delivers a low overpotential of 14 mV at 10 mA cm and a high mass activity of 46.47 A mg at 300 mV for alkaline HER, bypass those of commercial Pt/C (19 mV and 0.09 A mg , respectively).