CoFe ₂ O ₄ /Ag Heterocatalysts Grown on Carbonized Wood for Light‐Promoted Oxygen Evolution Reaction

Abstract The sluggish reaction kinetics of oxygen evolution reaction (OER) significantly limit the efficiency of electrochemical water splitting (EWS) process, making the development of efficient and stable OER electrocatalysts for sustainable EWS important but still challenging to achieve. Herein, a light‐assisted improved design of low‐budget carbonized wood (CW) with outstanding OER performance is developed by firmly growing CoFe ₂ O ₄ nanorods and Ag nanoparticles on the CW channels to form self‐supporting electrode (CoFe ₂ O ₄ /Ag‐CW). The coordination of active CoFe ₂ O ₄ /Ag and porous CW framework results in substantial effective interfaces and abundant electrochemical active sites, and accelerated electrolyte diffusion, electron transfer, and oxygen escaping. Electrochemical measurements and density functional theory calculations suggest the presence of dual microparticle synergies, conducive to optimizing the electronic structure of CoFe ₂ O ₄ /Ag‐CW and lowering the energy barrier of O‐H bond breaking in H ₂ O for remarkably enhanced OER activity. Under light field assistance, CoFe ₂ O ₄ /Ag‐CW exhibits excellent photothermal effect and carrier separation efficiency with ultralow overpotential of 258 mV and long‐term stability at 100 mA cm ⁻² . The photothermal effect and the generation of photogenerated carriers enhance OER dynamics and charge transfer efficiency, leading to improved OER performance under light exposure. Overall, the proposed strategy looks promising for efficient and low‐cost oxygen generation.