Microwave-assisted synthesis of cobalt phosphide using ionic liquid as Co and P dual-source for hydrogen evolution reaction

Cobalt phosphide nanoparticles (Co2P) were synthesized via microwave radiation or pyrolysis at 400 degrees C, and two ionic liquids (IL) were applied as the phosphorus and cobalt dual-source for fabricating Co2P. In the microwave radiation method, tetrabutylphosphonium tetrachlorocobaltate(II) ([P-4,P-4,P-4,P-4](2)[CoCl4]) with carbon nanotubes (CNTs) was utilized to obtain the Co2P/CNTs-1 via one step phosphidation within 6 min. These as-prepared materials were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The electrocatalytic performance of microwave-prepared Co2P/CNTs-1 toward hydrogen evaluation reaction was investigated in acidic solution, which shows a good catalytic activity with onset overpotential of 80 mV, Tafel slope of 58 mV dec(-1), current densities of 10 and 20 mA cm(-2) at overpotentials of 135 and 170 mV, respectively. This microwave-assisted strategy for synthesis of Co2P provides a remarkable advantage of preparation process in a quite short time, which also is a simple operation and energy efficient method. (C) 2018 Elsevier Ltd. All rights reserved.