Engineering Non-precious Trifunctional Cobalt-Based Electrocatalysts for Industrial Water Splitting and Ultra-High-Temperature Flexible Zinc-Air Battery.

Abstract

Developing efficient, robust, and cost-effective trifunctional catalysts for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) at high current density and high temperature is crucial for water splitting at industry-level conditions and ultra-high-temperature Zinc-air battery (ZAB). Herein, cobalt nanoparticles well-integrated with nitrogen-doped porous carbon leaves (Co@NPCL) by direct annealing of core-shell bimetallic zeolite imidazolate frameworks is synthesized. Benefiting from the homogeneous distribution of metallic Co nanoparticles, the conductive porous carbon, and the doped N species, the as-fabricated Co@NPCL catalysts exhibit outstanding trifunctional performances with low overpotentials at 10mAcm-2 for HER (87mV) and OER (276mV), long-lasting lifetime of over 2000h, and a high half-wave potential of 0.86V versus RHE for ORR. Meanwhile, the Co@NPCL catalyst can serve as both cathode and anode for water splitting at industrial conduction, and exhibit a stable cell voltage of 1.87V to deliver a constant catalytic current of 500mAcm-2 over 60h. Moreover, the excellent trifunctional activity of Co@NPCL enables the flexible ZAB to operate efficiently at ultra-high temperature of 70°C, delivering 162mWcm-2 peaks power density and an impressive stability for 4500min at 2mAcm-2 .