Surface-confined growth of Ru amorphous sub-nanoclusters on reductive Mn3O4: a strongly coupled interface engineering for efficient neutral hydrogen production†

Abstract

The electrochemical hydrogen evolution reaction (HER) under neutral conditions is of great importance but remains challenging for achieving practical hydrogen production due to additional water dissociation and a low proton supply rate. Herein, this work focuses on Ru amorphous sub-nanoclusters (Ru-ASNs), presenting an innovation that encompasses a surface-confined growth approach and a novel strongly coupled interface engineering strategy, wherein Ru-ASNs are grown on reductive Mn₃O₄ nanocrystals to form an interfacial catalyst (Ru-ASN/Mn₃O₄) for a superior neutral HER. The strongly coupled effect induced by Ru-ASNs on the heterostructure interface increases the proton supply rate by accelerating water dissociation at Mn sites as well as boosting hydrogen migration at Ru sites, thus resulting in improved HER activity and stability under neutral conditions. The resulting electrocatalyst demonstrates low overpotentials of −8 mV at −10 mA cm⁻² and −190 mV at −500 mA cm⁻² only at a low loading of 7 μg_Ru cm⁻² and a high mass activity of 8.78 A mg_Ru⁻¹ at −70 mV, and maintains stability for over 600 hours at −250 mA cm⁻², representing the highest mass activity of Ru-based electrocatalysts and longest durability under neutral conditions. This work demonstrates the superiority of amorphous sub-nanoclusters in constructing a strongly coupled interface for developing advanced catalysts.