Heterogenization of Ionic liquid Boosting Electrochemical Oxygen Reduction Performance of Co3O4 Supported on Graphene Oxide.

Electrochemical oxygen reduction is essential for a variety of sustainable energy application technologies. The development of non‐noble metal based electrocatalysts with durable stability and lower overpotentials is still a challenge. According to the reaction mechanism, the difficulty is originated from large equilibrium potential for *OO− formation and high instability of it. Here, we synthesized a 2D electrocatalytic material with nano‐Co3O4 supported on ionic liquid‐functionalized graphene oxide (Co3O4/IL−GO). Experimental results show the heterogenization strategy of IL enables anodic shifts of approximately 150 and 145 mV for the initial and half‐wave potentials, respectively, enabling Co3O4/IL−GO a comparable activity to the state‐of‐the‐art Pt/C catalyst. Moreover, Co3O4/IL−GO exhibits an excellent tolerance to methanol and superior long‐term stability over Pt/C making it a promising candidate for ORR in alkaline solutions. Theoretical calculations show the functionalized IL stabilizes the high‐energy Co−OO− intermediate through a strong pairing effect between the IL cation and the unstable *OO− adduct, and lowers the energy barrier for the subsequent Co−OOH formation, which enables the hybrid material a comparable activity and superior durability to Pt/C. To the best of our knowledge, this is the first exploration for heterogenization of IL onto electrode to stabilize crucial intermediates and subsequently boost the catalytic performance. [ABSTRACT FROM AUTHOR]