Although significant achievements have been made in the development of efficient transition metal phosphide (TMP) based electrocatalysts for hydrogen evolution reaction (HER) under acidic and alkaline media, TMP-based electrocatalysts with remarkable HER performances under neutral media has been rarely reported. Herein, we report the synthesis of nitrogen doped CoP nanoflower grown on conductive carbon cloth (N-CoP/CC) that possesses excellent HER performance, with an overpotential of 74 mV to achieve the current density of 10 mA cm⁻² in 1.0 M PBS (phosphate buffer solution, pH = 7), outperforming almost all the documented non-noble TMP-based electrocatalysts. In addition, the N-CoP/CC also displays Pt-like performance in 1.0 M KOH and 0.5 M H₂SO₄, with overpotentials of 39 and 25 mV to achieve the current density of 10 mA cm⁻², respectively. Density functional theory (DFT) calculations and experimental results reveal that doping with N can efficiently affect the electronic states of Co d-orbital and optimize the free energy of hydrogen adsorption (ΔG_*H) to the optimal value, resulting in enhanced HER performance.

    https://doi.org/10.1016/j.apcatb.2019.04.038