Dual-template synthesis of nitrogen-doped carbons spheres supported NiFe alloys towards improved electrocatalytic oxygen evolution

The development of transition metal/alloy materials has shown a promising prospect as the catalysts for electrochemical oxygen evolution reaction (OER). However, it is quite challenging to suppress the self-aggregation and promote the catalytic activity for metal nanoparticles (NPs). Decorating metal/alloy species onto nitrogen-doped carbon substrate is a powerful approach to fabricate the strongly-coupled nanohybrids. Herein, N-doped carbon spheres supported NiFe alloy nanoparticles (NiFe@NCS) are prepared through in-situ growth of NiFe-PBA nanocrystals on polydopamine (PDA) spheres, followed by a high-temperature pyrolysis. Thanks to the synergistic effect of hierarchical pore structure, high electronic conductivity, and plentifully active sites, the as-formed NiFe@NCS exhibits a low overpotential of 290 mV at a current density of 10 mA cm⁻² as well as displays a superb cycling stability for OER. In addition, the best catalytic activity has been realized for the NiFe@NCS sample with a moderate loading of NiFe NPs. This study affords a feasible dual-template method for fabricating efficient electrocatalysts of N-doped carbon-supported metal/alloy species.