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.