Amorphous/Crystalline ZrO2 with Oxygen Vacancies Anchored Nano-Ru Enhance Reverse Hydrogen Spillover in Alkaline Hydrogen Evolution

Small. 2025 Jan 6:e2410436. doi: 10.1002/smll.202410436. Online ahead of print.

Abstract

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 ZrO2. Theoretical and experimental results reveal that the water molecules dissociate on the Vo of ZrO2 into protons, which then couple with electrons to form H*, and the produced H* are spilled over to the nano-Ru to evolve H2. 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 ZrO2, facilitates electron transfer from ZrO2 to Ru, and thereby accelerates hydrogen spillover. As a result, the Ru/ac-ZrO2 delivers a low overpotential of 14 mV at 10 mA cm-2 and a high mass activity of 46.47 A mgmetal -2 at 300 mV for alkaline HER, bypass those of commercial Pt/C (19 mV and 0.09 A mgmetal -2, respectively).

Keywords: alkaline solution; amorphous; hydrogen evolution reaction; oxygen vacancy; reverse hydrogen spillover.