Well-defined CoP/Ni2P nanohybrids encapsulated in a nitrogen-doped carbon matrix as advanced multifunctional electrocatalysts for efficient overall water splitting and zinc-air batteries

Rational design of efficient multifunctional electrocatalysts is of significant importance for clean energy conversion and storage systems, such as water electrolysis, fuel cells and rechargeable metal-air batteries. Herein, well-designed CoP/Ni2P nanoparticles encapsulated in a nitrogen-doped carbon matrix (named as CoP/Ni2P@NC), derived from an organic-inorganic metal phosphonate precursor, can not only efficiently catalyze the hydrogen evolution reaction at all-pH ranges, but also exhibit outstanding activities for oxygen evolution and oxygen reduction reaction in an alkaline environment. When CoP/Ni2P@NC was used as both anode and cathode electrocatalysts for overall water splitting, a low cell voltage of 1.60 V was sufficient to drive a current density of 10 mA cm(-2). When employed as an air-cathode for rechargeable Zn-air batteries, CoP/Ni2P@NC shows a high peak power density of 77 mW cm(-2) and a long-term cycle life of 100 cycles. The remarkable electrocatalytic performance arises from the inherent catalytic activity of CoP/Ni2P, the unique N-doped core-shell structure and the strong synergistic interactions among CoP, Ni2P and N-doped carbon. This work is expected to inspire the design of advanced, multifunctional and performance-oriented organic-inorganic metal phosphonate-derived catalysts for sustainable energy conversion technologies.