Preparation of Co/CoOx Derived from a Low-temperature Etching of ZIF-67 for Oxygen Reduction and Oxygen Evolution Catalytic Reaction

Catalysts consisting of Zeolite imidazolyl ester skeleton-67 (ZIF-67) and graphene oxide (GO) were fabricated through a solvothermal method, followed by etching ZIF-67 with oxygen-rich functional groups on GO in a reduction atmosphere at 400 C-degrees. During this process, an open type of cobalt metal center was formed by the partial vaporization and oxidation of ZIF-67, further reducing to Co and partially combining with oxygen species to amorphous CoOx. Benefiting from the rich functional N, and metal/oxides active centers derived from the calcination process, the synthesized Co/CoOx@NSG-400 showed a low OER overpotential of 10 mA center dot cm(-2) at 298 mV, and an ORR half-wave potential of 0.8 V, which demonstrated its excellent bifunctional catalytic activity. Such a controllable calcination strategy with high yields could be expected to pave the way for synthesizing low-cost and efficient bifunctional electrocatalysts.