"d-electron interactions" induced CoVO-Fe-NF for efficient oxygen evolution reaction.

The investigation of cost-effective, highly efficient, and environmentally friendly non-noble-metal-based electrocatalysts is imperative for oxygen evolution reactions (OER). Herein, CoVO grown on nickel foam (NF) was selected as the fundamental material, and Fe is introduced through a simple Fe immersion treatment to synthesize CoVO-Fe-NF. Fe is transformed into high oxidation state Fe due to interactions between the 3d electrons of transition metals. Raman spectroscopy analysis reveals the specific process of OER in the presence of Fe. Being in a higher oxidation state, Fe provides more active sites, which is beneficial for the reaction between water molecules and the reactive sites of the electrocatalyst, ultimately enhancing the accelerated OER process. CoVO-Fe-NF exhibited an overpotential of only 298 mV at 100 mA cm in 1 M KOH electrolyte, which is lower than that of CoVO-NF (348 mV), as well as the comparative samples: Fe-NF (390 mV) and NF (570 mV). The exploration of high performance, triggered synergistically by the cooperative effect of transition metal 3d electrons, provides insights into the design of transition metal electrocatalysts for highly efficient OER.