Metal-organic framework derived Co@NC/CNT hybrid as a multifunctional electrocatalyst for hydrogen and oxygen evolution reaction and oxygen reduction reaction

Seeking a multifunctional electrocatalyst composed of earth-abundant elements for highly hydrogen and oxygen evolution reaction and oxygen reduction reaction (HER, OER and ORR) is technically imperative for the electrocatalytic applications. Herein, we report HER , OER and ORR electrocatalytic performances of metal-organic framework (MOF) derived cobalt nanoparticles encapsulated in nitrogen-doped carbon and carbon nanotube (Co@NC/CNT). The optimized Co@NC/CNT hybrid shows superior HER and OER activities with a small overpotential of 137 mV and 302 mV at a current density of 10 mA cm −2 , respectively. Furthermore, the Co@NC/CNT as an air-cathode in secondary Zn-air battery demonstrates a confined potential gap of 0.88 V over 200 h and a maximum power density of 53.4 mW cm −2 , which are much better than those of Pt/C. The outstanding performances are attributed to the synergistic effects from Co, and N embedded into carbon and CNT. More importantly, the unique surface structure contributes to expose many active sites for superior catalytic activity through allowing a large number of electrons. These outcomes not only prove a facile approach for the preparation of metals/carbon hybrid but also disclose its huge possible as a multifunctional electrocatalyst for sustainable energy systems .