Engineering a local potassium cation concentrated microenvironment toward the ampere-level current density hydrogen evolution reaction

Abstract

Finding an active and robust non-platinum catalyst toward the alkaline hydrogen evolution reaction (HER) operating at an ampere-level current density is important for emerging anion exchange membrane (AEM) water electrolysis but challenging. Here we report a nanocone-assembled Ru₃Ni (NA-Ru₃Ni) catalyst that exhibits a low overpotential of 168 mV at 1000 mA cm⁻² and a high turnover frequency of 26.5 s⁻¹ at an overpotential of 100 mV, with a Ru₃Ni loading of only 0.08 mg cm⁻². Moreover, the catalyst could stably operate at 1000 mA cm⁻² over 2000 h in a practical AEM electrolyser at 60 °C, showing the best overall performance among ever-reported catalysts. The theoretical simulations and experimental results confirm that the sharp-tip concentrated K⁺ cations contribute to such remarkable alkaline HER activity by intensifying the polarization of the H–OH bond of interfacial water and decreasing the energy barrier for water dissociation, where the non-covalent interaction is considered as the intrinsic driving force. The present work provides general guidance for the rational design of industrially relevant alkaline HER catalysts.