One-step construction of Co2P nanoparticles encapsulated in N, P co-doped biomass-based porous carbon as bifunctional efficient electrocatalysts for overall water splitting

Abstract

Developing efficient active transition metal phosphide (TMP) bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for alleviating the future energy crisis is crucial and challenging. Herein, we developed a facile self-assembly strategy for the one-step fabrication of core–shell Co₂P nanoparticles encapsulated in nitrogen and phosphorus codoped porous carbon (Co₂P@NPPC) via in situ carbonization and phosphorization. Due to the collaborative effect between NPPC and Co₂P, the obtained Co₂P@NPPC hybrid revealed robust electrocatalytic performance toward the HER and OER. Impressively, it exhibited a lower overpotential of 147 mV for HER and 316 mV for OER to reach the current density of 10 mA cm⁻². Remarkably, it only required a low cell voltage of 1.65 V to reach the current density of 10 mA cm⁻², with long-time reliable stability. Density functional theory (DFT) calculations suggest that the introduction of phosphorus into cobalt can weaken the H-adsorption free energy and increase the electronic states of Co₂P.