Multicomponent Interface and Electronic Structure Engineering in Ir-Doped CoMO₄–Co(OH)₂ (M = W and Mo) Enable Promoted Oxygen Evolution Reaction

The core principles of multicomponent interface and electronic structure engineering are essential in designing high-performance catalysts for the oxygen evolution reaction (OER). However, combining these aspects within a catalyst is a significant challenge. In this investigation, a novel approach involving the development of hybrid Ir-doped CoMO₄-Co(OH)₂ (M = W and Mo) hollow nanoboxes was introduced, enabling remarkably efficient water oxidation electrocatalysis. Constructed from ultrathin nanosheet-assembled hollow nanoboxes, these structures boast a wealth of active centers for intermediate species, which in turn enhance both charge transfer and mass transport capabilities. Moreover, the compelling electronic and synergistic effects arising from the interaction between CoMO₄ and Co(OH)₂ significantly bolster OER electrocatalysis by facilitating efficient electron transfer. The introduction of Ir atoms serves to strategically adjust the electronic structure, fine-tune its electronic state, and operate as active centers to enhance OER electrocatalysis, thus diminishing the overpotential. This configuration results in Ir-CoWO₄-Co(OH)₂ and Ir-CoMoO₄-Co(OH)₂ exhibiting impressively low overpotentials of 252 and 261 mV, respectively, to 10 mA cm^-2. Utilized in conjunction with the Pt/C catalyst in a two-electrode system for overall water splitting, a mere 1.53 V cell potential is needed to achieve the desired 10 mA cm^-2 current density.