Self-supported CoMoO4/NiFe-LDH core–shell nanorods grown on nickel foam for enhanced electrocatalysis of oxygen evolution

Abstract

Developing high-performance catalysts is an effective strategy for speeding up the oxygen evolution reaction (OER) and increasing production efficiency. Here, a core–shell electrocatalyst consisting of CoMoO₄ nanorods grown in situ on nickel foam substrate covered by nickel–iron layered double hydroxide (NiFe-LDH) via electrodeposition was demonstrated (CoMoO₄/NiFe-LDH@NF). Experimental investigations revealed that self-supporting and binder-free electrodes ensured that the catalysts exposed an abundance of active sites, faster electron transfer, and excellent long-cycle stability. The NiFe-LDH shell with a crystalline-amorphous dual structure served as an accurate active material, lowering the energy barrier and contributing more catalytic sites for water oxidation. Furthermore, the core CoMoO₄ nanorods not only effectively avoided the accumulation of NiFe-LDH to increase the electrochemically active area but also acted as a highway for electrons from the active site to the substrate to promote the OER kinetics. Specifically, CoMoO₄/NiFe-LDH@NF exhibited lower overpotential (180 mV at 10 mA cm⁻²) and smaller Tafel slope (34 mV dec⁻¹) than pure CoMoO₄@NF and NiFe-LDH@NF, revealing its excellent catalytic performance and fast intrinsic reaction kinetics. In addition, CoMoO₄/NiFe-LDH@NF exhibited long-term stability of more than 20 h at 50 mA cm⁻², further demonstrating its potential for practical applications. These findings pointed to a potential option for building innovative OER catalysts.