Boosting Alkaline Hydrogen Evolution on RuO 2 : Regulation of Intermediate Binding by Keggin-Type Polyoxometalates

Abstract

Efficient, low-cost electrocatalysts are essential for sustainable hydrogen production via the alkaline hydrogen evolution reaction (HER). While ruthenium oxide (RuO2) is conductive and stable, its HER activity is hampered by unfavorable intermediate adsorption. Herein, we report a significant enhancement of the HER performance of RuO2 through coupling with Keggin-type polyoxometalates (POMs). A self-supported POM-RuO2/Ti electrode was fabricated via a one-step hydrothermal method, forming a composite of low-crystallinity RuO2 and POM clusters (PMo12 or PMo10V2) on a titanium substrate. Electrochemical tests in 1 M KOH demonstrated that the PMo10V2-RuO2 composite requires an ultralow overpotential of 56 mV at 10 mA /cm 2 , surpassing Pt/C, alongside a small Tafel slope (48.2 mV/dec) and robust stability. Spectroscopic and DFT analyses revealed that POM clusters act as electron acceptors, tailoring the electronic structure of Ru sites, downshifting the d-band center, and optimizing hydrogen adsorption. This work not only underscores POMs as a powerful strategy for unlocking the potential of RuO2 but also establishes a new paradigm for advanced electrocatalyst design.