Construction of heterophase MoOx/Ru assisted by self-assembled carboxymethylcellulose-Ru3+ nanosheet for improved alkaline hydrogen evolution

Abstract

The hydrogen evolution reaction (HER) in alkaline medium is much sluggish than that in acidic medium due to the limited water dissociation step, thus accelerating the water dissociation kinetics is critical. Herein, we designed a MoOx species-modified ruthenium nanoparticle catalyst (MoOx/Ru/C-3) based on the unique electrostatic interaction between carboxymethylcellulose sodium salt (CMC) and metal ions, where an heterophase structure is formed between MoOx and Ru. The obvious electronic interaction between them allows the formation of synergistic promotion relationship involving the water dissociation on MoOx and the adsorbed hydrogen recombination on Ru. At a metal loading of 6.98 μgRu cm-2 geo, the overpotential of 82 mV is just required to reach a current density of 10 mA cm−2, exhibiting a significantly better apparent electrochemical activity than Ru/C (98 mV) without introduction of MoOx, which demonstrates superior or comparable alkaline HER activity to the recently reported Ru-based electrocatalysts. Meanwhile, the overpotential for Ru/C increased by 113 mV after 24 h of chronopotentiometric test, whereas only 61 mV elevates for MoOx/Ru/C-3, and even just 98 mV generates after 120 h. Thereof, introduction of MoOx species into Ru matrix can also markedly improve the electrochemical stability. The proposed material construction strategy in this study provides a feasible idea for the rational design of highly cost-performance alkaline hydrogen evolution catalysts.