Bifunctional hydrogen evolution and oxygen evolution catalysis using CoP-embedded N-doped nanoporous carbon synthesized via TEOS-assisted method

Bifunctional electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of fundamental significance for efficient solar-water splitting devices. Herein, we report the preparation of CoP nanoparticles embedded in N-doped mesoporous carbon via a simple yet facile route involving the polymerization of dopamine, Co salts and Si precursor, as well as the subsequent phosphidation treatment. The as-prepared catalysts not only can efficiently catalyze the HER in acidic and basic media with overpotential of 139 and 203 mV to reach current density of 10 mA cm⁻², but also favors the sluggish OER process due to the presence of cobalt oxy-hydroxide on the surface of CoP, showing overpotential of 345 mV to acquire the same current density. The efficient catalytic activities are, highly probably, attributed to the favorable mass-transfer in the nanoporous carbon, interfacial effects at nitrogen dopants enriched site, small charge transfer resistance, as well as synergistic effect between active species and underlying support. The catalysts are appealing to serve as the promising bifunctional electrocatalysts for overall water-splitting with overpotential of 1.72 V to reach current density of 10 mA cm⁻².