Nitrogen-doped carbon confined NiFe-NiFeP nanocubes immobilized on carbon nanotube as an efficient electrocatalyst for oxygen evolution reaction

The future sustainable energy related application, especially Zn-air batteries (ZABs) and electrochemical water splitting to produce hydrogen, are limited by oxygen evolution reac-tion (OER). Transition metal phosphides have excellent catalytic activity for OER, but their poor conductivity and bad stability still require to be solved. Herein, the nitrogen-doped carbon (NC) confined NiFe-NiFeP nanocubes immobilized on carbon nanotube (CNT) (NiFe-NiFeP@NC/CNT) is fabricated by employing NiFe-Prussian Blue Analogs (NiFe-PBAs) nanocubes and CNT composite as precursor, and subsequent polydopamine (PDA) coating, carbonization and partial phosphorization. Profiting from its unique "nanonecklaces" structure with conductive CNT and ordered NiFe-NiFeP@NC nanocubes, NiFe-NiFeP@NC/ CNT provides an efficient electron transfer path and uniformly dispersed active sites for OER process. The optimized NiFe-NiFeP@NC/CNT exhibits a low overpotential of 228 (328) mV at 10 (100) mA cm-2 and high durability. Furthermore, the NiFe-NiFeP@NC/CNT || Pt/C requires 1.51 V to realize 20 mA cm-2 for overall water spitting. And the ZAB assembled with NiFe-NiFeP@NC/CNT shows excellent discharge-charge stability for 240 h. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.