3D Core–Shell NiFeCr Catalyst on a Cu Nanoarray for Water Oxidation: Synergy between Structural and Electronic Modulation

Low-cost transition metal-based electrocatalysts for water oxidation and understanding their structure–activity relationship are greatly desired for clean and sustainable chemical fuel production. Herein, a core–shell (CS) NiFeCr metal/metal hydroxide catalyst was fabricated on a 3D Cu nanoarray by a simple electrodeposition–activation method. A synergistic promotion effect between electronic structure modulation and nanostructure regulation was presented on a CS-NiFeCr oxygen evolution reaction (OER) catalyst: the 3D nanoarchitecture facilitates the mass transport process, the in situ formed interface metal/metal hydroxide heterojunction accelerates the electron transfer, and the electronic structure modulation by Cr incorporation improves the reaction kinetics. Benefiting from the synergy between structural and electronic modulation, the catalyst shows excellent activity toward water oxidation under alkaline conditions: overpotential of 200 mV at 10 mA/cm2 current density and Tafel slope of 28 mV/dec. This work opens up a new window for understanding the structure–activity relationship of OER catalysts and encourages new strategies for development of more advanced OER catalysts.