Plasma-enhanced alternating atomic layer deposition of nickel and copper oxide on wood-derived monolithic carbon electrode for robust oxygen evolution reaction

The oxygen evolution reaction (OER) is a critical half-reaction that occurs at the anode for water electrolysis, along with sluggish kinetics and high overpotential owing to its four-electron transfer process. Iridium-based electrocatalysts are recognized as the superior OER performance, but are limited by high cost and shortage reserves. Hence, we report a monolithic electrode with Ni doped Cu_2-xO growth on the carbonized wood (CW) surface by an alternating plasma-enhanced atomic layer deposition (PEALD) strategy. The alternating deposition of Ni and Cu_2-xO ensures uniform doping of Ni and facilitates the electron transfer from d-orbital of Cu²⁺ to the Ni site. This electron transfer reduces electron repulsion among the p-orbitals of the coordinated O atoms, enhancing the local metal-oxygen bonding strength and adjusting the charge at the Cu site. Consequently, the electronic structure of the catalyst is optimized, leading to exceptional OER performance with an overpotential of 110.2 mV at 10 mA cm⁻² and significantly enhanced stability of 75 h.