Boosting OER Performance of NiFe-MOFs via Heterostructure Engineering: Promoted Phase Transformation and Self-optimized Dynamic Interface Electron Structure

How to manipulate heterostructure engineering to achieve high-efficiency oxygen evolution reaction (OER) remains a significant challenge. Herein, a promising OER heterostructure electrocatalyst with IrNi nanoalloys (≈3.29 ± 0.12 nm) anchored on NiFe-MOFs (IrNi@NiFe-MOFs), exhibiting promoted phase transformation and self-optimized dynamic interface electronic structure, via a one-step hydrothermal method is designed and developed. Specifically, IrNi@NiFe-MOFs displays excellent OER performance with a low overpotential of 228 mV at 10 mA cm⁻², a small Tafel slope of 37.6 mV dec⁻¹, and robust stability at 10 and 100 mA cm⁻². Experimental and theoretical calculations identify the actual active sites as IrNi@NiFeOOH and further reveal that the dynamic structure evolution and self-optimized dynamic interface electron structure, promoted by heterostructure engineering, boost its OER catalytic performance. Moreover, IrNi@NiFeOOH heterostructure displays strong interface electron interactions and a unique self-optimized dynamic interface electron structure, resulting in better charge redistribution and adaptive bonding (Ir─O─Ni/Fe bonds). This structure therefore plays a critical role in promoting electron transfer, facilitating the dynamic evolution of reaction intermediates, and reducing the energy barrier of the potential-determining step, thereby boosting the OER performance. These findings provide new insights into the development of MOF-based electrocatalysts via heterostructure engineering.