Rising energy demands and environment problems have promoted extensive research on the development of alternative energy resources and storage devices with high efficiency and environmental friendliness. Among them, water splitting is a promising strategy for the formation of clean energy resource and storage but the main challenge of this renewable-energy technology is to enhance the kinetics of oxygen evolution reaction (OER). Therefore, developing efficient electrocatalysts with high catalytic activities and stability is of great importance for high-performance water splitting. Recently, a considerable amount of research has been devoted to the development of new OER electrocatalysts with low-cost, highly efficient, and excellent stability properties [1]. Transition metal phosphides (TMPs) and their composite-based catalysts are extensively used for replacing previously used noble metals such as Pt, Au, and Ag due to scarcity, instability, and high price. Predominantly, nickel and cobalt phosphides based materials among all TMPs have proven to be excellent catalysts for water splitting [2], because these catalysts have shown some of advantages, such as high conductivity, earth abundance reserves, and good physicochemical properties. In this research, carbon fiber cloth (CFC) supported with high mass loading of cobalt phosphide and graphitic carbon nitride (g-C3N4) was synthesised through a three-step process consisting of cobalt electrodeposition at -10 V for 3 s, followed by CVD growth of g-C3N4 at 950 °C by using melamine as precursor and finally phosphorization treatment in inert atmosphere. This CoP/g-C3N4@CFC electrocatalyst demonstrated a superior electrocatalytic performance for OER activity, and excellent durability in alkaline media under 1000 sweeps at a high scan rate 100 mV s−1. Remarkably, the CoP/g-C3N4@CFC exhibited a low overpotential of 270 mV to deliver 10 mA cm-2 current density. Moreover, the synthesized electrocatalysts were charecterized by several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and map element analysis to confirm the formation of CoP and g-C3N4 with special morphology on the surface of CFC.
