C60-Decorated nickel–cobalt phosphide as an efficient and robust electrocatalyst for hydrogen evolution reaction

Abstract

High-activity electrocatalysts play a crucial role in energy conversion through splitting water to produce hydrogen. Here we report the synthesis of a bimetallic phosphide of Ni–Co–P coupled with C₆₀ molecules which acts as an electrocatalyst for the hydrogen evolution reaction (HER). Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterization reveals that the synthesized C₆₀-decorated Ni–Co–P nanoparticles have an average diameter of ∼4 nm with rich structural defects. Electrochemical tests show that the as-synthesized C₆₀-decorated Ni–Co–P catalyst with a C₆₀-content of 3.93 wt% presents a low onset overpotential of 23.8 mV, a small Tafel slope value of 48 mV dec⁻¹, and excellent hydrogen-evolution stability with a slight increase of its η₁₀ from 97 mV to 102 mV after 500 cycles. Additionally, electrochemical impedance spectroscopy (EIS) confirms that the C₆₀-decorated Ni–Co–P electrode possesses faster charge-transfer kinetics and hydrogen-adsorption kinetics than the C₆₀-free Ni–Co–P electrode during the HER process. The synthesis of a C₆₀-decorated composite is feasible and the composite can be used as an efficient and robust Pt-free catalyst.