Surface/interface engineering for fabricating hierarchical Ir doped NiMoO4 covered by CoMn layered double hydroxide toward oxygen evolution reaction

Abstract

Designing and fabricating outstanding electrocatalysts for anodic oxygen evolution reaction plays a key role in driving the earlier application of water splitting for large-scale hydrogen production. Surface/interface engineering is regarded as the most effective method for activating the active sites and modulating the electronic structure, which are two crucial factors determining the electrocatalytic performance. Herein, amorphous CoMn LDH ultrathin nanosheets doped by Ir are integrated with low-crystalline NiMoO4 nanorods (Ir-NiMoO4/Ir-CoMn LDH) to fabricate advanced hierarchical OER electrocatalysts. The optimized Ir-NiMoO4/Ir-Co3Mn2 LDH exhibits excellent OER performance as attested by an ultralow overpotential of 221 mV at the current density of 10 mA cm−2, as well as superb long-term durability. The intimate interface between NiMoO4 and Co LDH and modified electronic structure induced by Ir and Mn doping can greatly optimize the binding strength of between active sites and intermediated species, which improves the electrocatalytic OER performance. This study manifests how the synergistic surface/interface engineering design of nanomaterials boosts their catalytic activity.