NiCoP/CoP Nanoparticles Supported on Ti4O7 as the Electrocatalyst Possessing an Excellent Catalytic Performance toward the Hydrogen Evolution Reaction

NiCoP/CoP nanoparticles and NiCoP/CoP nanoparticles supported on carbon black (NiCoP/CoP-C) and titanium suboxide (NiCoP/CoP-Ti4O7), respectively, are prepared by a hydrothermal method followed by two steps of low temperature annealing processes. As hydrogen evolution reaction (HER) catalysts, the activities of the three catalysts are measured by linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and so on. Impressively, NiCoP/CoP Ti4O7 shows the best electrocatalytic performance for HER with an ultralow overpotential of 128 mV at 10 mA cm(-2) along with negligible catalytic activity degradation after 1000 cycles of CV, which is partly ascribed to the high conductivity and corrosion resistance of Ti4O7. According to the characterization of X-ray photoelectron spectra (XPS), it is found that NiCoP/CoP Ti4O7 has a higher ratio of Ni2+ and surface defects, which can be also used to explain the reason why NiCoP/CoP Ti4O7 owns the most preeminent HER activity among the three catalysts.