Efficient electrocatalytic proton reduction on CoP nanocrystals embedded in microporous P, N Co-doped carbon spheres with dual active sites

A facile and scalable method is reported to develop CoP nanocrystals encapsulated in a P, N co-doped C matrix (PNC) as a highly efficient electrocatalyst for hydrogen evolution reaction (HER) in acidic and basic media. The synthesized CoP-PNC electrocatalysts exhibit large specific surface area of 1543 m² g⁻¹, hierarchical microporous structure, and high density of surface -active sites. The porous CoP-PNC electrocatalysts exhibit excellent HER electroactivity, delivering a current density of 10 mA cm⁻² at very low overpotentials of 87 and 106 mV in 0.5 M H₂SO₄ and 1 M KOH electrolytes, respectively. This remarkable HER performance mainly arises from the synergic effect between CoP and P, N co-doped C, high density of active sites and large surface area due to the multiple pore structures. Most importantly, the CoP-PNC retains high stability even after 40 h of continuous electrolysis in extremely acidic (pH = 0) and basic solutions (pH = 14).