Approaching high oxygen evolution reaction performance by synergetic dual-ion leaching

Self-reconstruction of catalysts during oxygen evolution reaction (OER) is crucial for the development of energy conversion technologies. However, the relationship between the specific atomic structure of pre-catalysts and their electrocatalytic behavior after reconstruction via dual-ion leaching has not been extensively researched. In this work, we design a highly effective non-noble metal OER catalyst with heterointerface through continuous self-reconstruction of Co₂(OH)₃Cl@NiMoO₄ as pre-catalyst by a straightforward dual-ion (i.e. MoO₄²⁻ and Cl⁻) leaching. In-situ Raman and in-situ Fourier transform infrared (FT-IR) spectroscopy have precisely identified the progressive phase transformation of the pre-catalyst during self-reconstruction, which results in a stable heterojunction of CoOOH and NiOOH (CoOOH@NiOOH). Further calculations based on density functional theory (DFT) of CoOOH@NiOOH evident that more electrons will be aggregated in the Fermi level of Co. Notably, Gibbs free energy (ΔG) for different OER steps of CoOOH@NiOOH exhibit lower energy costs of all intermediates, implying the well catalytic properties. Ultimately, the catalyst derived from dual-ion leaching displays outstanding OER performance, characterized by an overpotential of 275 mV at a current density of 10 mA·cm⁻² and exceptional stability over 12 h reaction. This work successfully paves a way of finding high-performance OER catalysts based on non-noble metal through dual-ion leaching during self-reconstruction.