Structure and surface optimization of NiFeP-based heterostructure immobilized on carbon nanotube for boosting electrocatalytic oxygen evolution

Oxygen evolution reaction (OER) has received extensive attention because it is the key reaction for various electrochemical energy conversions, such as electrochemical water splitting. Transition-metal phosphides (TMPs) have been identified as potential OER electrocatalysts. However, it is a challenge to design and optimize the structure of TMPs to achieve high catalytic performance. Herein, the unique “nanonecklaces” electrocatalyst (NiFe-NiFeP@NC-NiFeP/CNT) comprised of carbon nanotube (CNT), NiFe-NiFeP particles with N-doped carbon layer coating, and NiFeP nanoparticles was successfully constructed. The experiment results demonstrate that the unique “nanonecklaces” structure provides excellent charge transfer channel, and the heterostructure adjusts the electronic structure of the catalyst, resulting in outstanding electrocatalytic activity. Additionally, the NC protective layer effectively prevents active site from corrosion and enhances the catalyst stability. Furthermore, the NiFeP adsorbed regulates the surface properties, which provides abundant surficial active sites, thus significantly improves the catalytic activity. Benefiting from these advantages, the optimized catalyst exhibits excellent oxygen evolution capability, reaching 10 (100) mA cm ^-2 at low overpotential of 214 (288) mV, and can electrolyze continuously for 120 h. This work presents a promising method for manipulating the component and nanostructure to design highly active and stable catalytic for OER.