Green Synthetic NiCoP Nanoparticles Encapsulated in N-Doped Carbon for Water Splitting

Transition metal phosphides (TMPs) have drawn widespread attention as promising electrocatalysts due to their special electronic structure, good electrochemical activity, low cost, and high abundance. Although a great deal of effort has been expended in the pursuit of TMPs, the majority of synthesis processes are complex and hazardous due to the use of flammable and toxic phosphorus sources. Herein, we propose a nontoxic and scalable synthetic strategy for the synthesis of NiCoP@NC by using green and cheap diethylenetriaminepentakis (methylphosphonic acid) (DTPMP) as the phosphorus source. DTPMP can also act as a chelating agent and displays strong coordination ability with metal ions, thereby reducing particle size and forming nanoparticles. The NiCoP@NC exhibits outstanding stability and electrocatalytic activity in both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Furthermore, water electrolysis performance also is measured using NiCoP@NC as both anode and cathode, which delivers a cell voltage of 1.73 V at 10 mA<middle dot>cm-2 and can operate stably for 24 h. This work not only constructs efficient bifunctional catalysts, but also broadens the green synthesis method of nanosized TMPs, paving the way for further large-scale practical applications.