Supramolecular assisted one-pot synthesis of donut-shaped CoP@PNC hybrid nanostructures as multifunctional electrocatalysts for rechargeable Zn-air batteries and self-powered hydrogen production

Abstract

The renewable energy utilization largely relies on the development of highly efficient energy conversion devices including metal-air batteries and water electrolyzers. Currently, it is crucial yet challenging to explore multifunctional nonprecious electrocatalysts with high activity toward oxygen and hydrogen electrodes. Herein, unique donut-shaped hybrid nanostructure composed of interconnected CoP nanoparticles within P, N co-doped carbon matrix (denoted as CoP@PNC-DoS) was successfully fabricated through a supramolecular assisted one-pot strategy. Thanks to the unique morphology and modulated composition, the CoP@PNC-DoS manifested excellent universal electrocatalytic activity for both oxygen and hydrogen electrodes, where a small potential gap of 0.781 ​V (ΔE ​= ​Ej10-E1/2) between ORR and OER and a low overpotential of 173 and 160 ​mV to reach the current density of 10 ​mA ​cm−2 in 1 ​M KOH and 0.5 ​M ​H2SO4 for HER can be achieved. The CoP@PNC-DoS based Zn-air battery could provide an impressive peak power density of 138.57 ​mW ​cm−2, and more importantly, a prominent charge/discharge stability after 150 ​h/350 cycles under a current density of 30 ​mA ​cm−2, demonstrating its feasibility as cathode electrocatalyst for rechargeable Zn-air batteries. More importantly, a proof-of-concept system integrating Zn-air battery powered water splitting was further built to achieve cost-effective H2 production.