Facile synthesis of MOF-Derived Co@CoNx/bamboo-like carbon tubes for efficient electrocatalytic water oxidation

The development of economical noble metal-free electrocatalysts for oxygen evolution reaction (OER) with high catalytic activity and durability is crucial for the practical applications of many energy storage and conversion technologies. Here, we report a facile and economical synthesis of Co@CoNx/N-doped carbon tubes hybrid (Co@CoNx/NCT hybrid) via one-step pyrolysis of ZIF-67 at a low temperature of 650 degrees C with the introduction of urea, which functions as both nitrogen source and promoter of carbon tube growth. The resultant Co@CoNx/NCT hybrid exhibits bamboo-like structure with numerous active sites originated from abundant CoNx species, high nitrogen doping level and topological defects, rendering excellent catalytic activities towards OER in alkaline medium. As a result, the as-obtained Co@CoNx/NCT hybrid shows an overpotential of as low as 290 mV at a current density of 10 mA cm(-2) with a small Tafel slope of 60 mV dec(-1), which outperforms most noble metal-free electrocatalysts and even commercial IrO2 . Therefore, the Co@CoNx/NCT hybrid holds great promise for efficient electrocatalytic water oxidation applications. (C) 2018 Published by Elsevier Ltd.