Cobalt-nickel phosphides@carbon spheres as highly efficient and stable electrocatalyst for hydrogen evolution reaction

In this study, a low-cost cobalt‑nickel [email protected] spheres was developed as catalyst for the hydrogen evolution reaction (HER) via a facile two-step method. The structure of as-prepared phosphides was characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and N2 adsorption-desorption isotherms. In the 0.5 M H2SO4 electrolyte, the optimized sample, namely Co1Ni1[email protected], delivers an overpotential of 169 mV for HER at the current density of 10 mA cm−2 with excellent stability. The results showed that the composition of obtained cobalt‑nickel phosphides plays a critical role in enhancing the HER electrocatalytic performance.