Metal–Organic Framework-Derived Co_xFe_1–xP Nanoparticles Encapsulated in N-Doped Carbon as Efficient Bifunctional Electrocatalysts for Overall Water Splitting

Developing low-cost and high-performance bifunctional electrocatalysts is an essential prerequisite for obtaining clean hydrogen energy via overall water splitting. Herein, we present a metal–organic framework-derived route for the synthesis of N-doped carbon encapsulated CoxFe1–xP nanoparticles (CoxFe1–xP/NC), which show remarkable electrocatalytic activity toward both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. The optimized Co0.17Fe0.79P/NC shows low overpotentials at a current density of 10 mA cm–2 (139 and 299 mV) and small Tafel slopes (57 and 44 mV dec–1) for HER and OER, respectively. The water electrolyzer using Co0.17Fe0.79P/NC as both anode and cathode reaches the current density of 10 mA cm–2 at a voltage of 1.66 V, and exhibits excellent long-term stability for 35 h. These excellent catalytic performances are mainly ascribed to the facile NC scaffold and slight Co incorporation, which provide large surface contact area between catalyst and electrolyte, fast charge and mass transport pathways, and abundant and stable active sites.