Mechanistic insight into a Co-based metal–organic framework as an efficient oxygen electrocatalyst via an in situ FT-IR study

Abstract

The slow rate of reaction and significant energy consumption associated with the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are acknowledged as substantial obstacles within the realm of electrocatalysis. Hence, the quest for cost-effective and exceptionally efficient electrocatalysts for the ORR/OER holds huge demand to enhance energy conversion and storage capabilities. Herein, we have synthesized a cobalt-imidazole-tetracarboxylate metal–organic framework (Co-MOF) and further modified it with graphene (G) by an electrophoretic exfoliation technique to develop a conducting electrocatalyst (Co-MOF/G). The heterogeneous electrocatalyst is successfully utilized as a bi-functional catalyst towards the ORR and OER in alkaline media. The half-wave potential for the ORR and overpotential for the OER of the as-synthesized electrocatalysts were obtained at 0.78 V vs. RHE, and 302 mV vs. RHE, respectively. In situ Fourier transform infrared (FT-IR) spectroscopy coupled with an electrochemical technique reveals the intermediates formed during the reactions that help to draw the mechanism for the ORR and OER electrocatalytic processes. This approach opens up new possibilities for sustainable, low-cost and user-friendly catalysts for Zn–air batteries that might be a good alternative for future electronic applications.