Interface-engineered urchin-like CoFe-layered double hydroxide for high-efficiency electrocatalytic oxygen evolution

Abstract

The oxygen evolution reaction (OER) is the key anode reaction for electrochemical water splitting, but it is severely hindered by the sluggish reaction kinetics and insufficient stability of traditional electrocatalysts. To address the urgent need for efficient and low-cost electrocatalysts, a promising heterogeneous CoFe-layered double hydroxide-based electrocatalyst (Ce@CoFe-LDH) is developed by a one-step hydrothermal method combined with rapid electrodeposition. The ultrafine Ce(OH)₃ nanoparticles effectively trigger the local surface activity of CoFe-LDH nanowires by the interface electron transfer, thereby promoting the improvement of OER activity and stability. Consequently, the Ce@CoFe-LDH electrocatalyst only needs a 207 mV overpotential to reach 10 mA cm⁻², while the Tafel slope is only 50.0 mV dec⁻¹, smaller than those of the CoFe-LDH catalyst (232 mV, 74.2 mV dec⁻¹, respectively). Importantly, the Ce@CoFe-LDH electrocatalyst exhibits remarkable catalytic durability toward the OER at 100 mA cm⁻² over 120 hours. First-principles theoretical calculations reveal that interface engineering can be used to optimize the electronic structure of Ce@CoFe-LDH by charge redistribution and thereby decrease the energy barrier of the rate-determining step. In addition, the Ce@CoFe-LDH electrocatalyst as an anode for water splitting also shows a low cell potential of 1.47 V at 10 mA cm⁻² and robust stability at 100 mA cm⁻² over 50 hours. Overall, this work provides new insights into designing efficient OER electrocatalysts for scalable water splitting in clean energy and environmental applications.