Abstract
Oxygen reduction and evolution reactions (ORR and OER, respectively) are the two most extensively studied reactions in electrochemistry. Herein, we report the synthesis of Co3O4/CeO2/GNP (GNP=graphene nanoplatelet) electrocatalyst for ORR and OER that exhibits an early onset potential (0.85 V) and half‐wave potential (E1/2) of 0.69 V for ORR. The reported catalyst is highly durable with 87.6% retention of its initial current after a 6 h chronoamperometry test compared to 72.5% by Pt/C. It exhibits a negligible shift of E1/2 after 10,000 potential cycles for ORR. Heterogeneous oxide/oxide interfaces, oxygen vacancies and semicrystalline nature are inferenced to play a dominant role in altering the collective catalytic efficiency of Co3O4/CeO2/GNP. High concentration of oxygen vacancy defects (68%) in Co3O4/CeO2/GNP is presumed to play a dominant role here. The catalyst is bifunctional for ORR and OER with a bifunctionality index of 0.98 V and operates at an overpotential of ƞ10= 440 mV for OER. Ex‐situ X‐ray absorption studies indicate an increased average oxidation state of Co by 15% in Co3O4/CeO2/GNP compared to Co3O4/GNP, aiding in preserving its inherent catalytic nature of spinel Co3O4.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call