Integrating NiMoO wafer as a heterogeneous ‘turbo’ for engineering robust Ru-based electrocatalyst for overall water splitting

Abstract

• Hybrid nanostructure of RuO 2 and NiMoO was fabricated via highly matched lattices. • Integrated NiMoO works like a turbo through optimizing the intermediates adsorption. • RuO 2 -NiMoO exhibits enhanced electrocatalytic activity for overall water splitting. • The synergy among geometric, electronic, and interfacial structures is crucial. Cooperative promotions of intrinsic activity, active sites amount, and mass transfer/charge transport in electrocatalytic process are highly depending on the fundamental understanding of reaction mechanism and the systematic and elaborate designing of morphological, electronic, and interfacial structure of electrocatalyst. Herein, a hybrid nanostructure of RuO 2 strongly coupled with structurally controllable NiMoO wafer arrays was elaborately fabricated via highly matched lattices for superior alkaline water electrolysis through optimizing the adsorption energies of the key intermediates at the interface based on synergistic electronic, geometric, and interfacial effects. The incorporation of Mo ion can adjust the electronic structure of host NiO x endowing the resultant NiMoO with suitable H and O intermediate binding energy for active species transfer between the interfaces. The ratio of O/C on the surface of flexible carbon cloth was well tuned through O 2 -plasma to achieve the desired geometric structure of NiMoO wafers with features of rich porosity and abundant active site. The RuO 2 nanoparticles are homogeneously distributed on the surface of porous NiMoO wafers via highly matched lattices, thereby offering efficient interfacial synergy. Consequently, the hybrid nanostructure of Ru species and NiMoO exhibits greatly enhanced bifunctional electrocatalytic activities toward both HER and OER for overall water splitting. The integrated NiMoO wafer works like a turbo for engineering robust Ru-based bifunctional electrocatalyst. The finding may provide insights for the rational design of advanced nanocomposite catalysts for various energy conversion applications.