Ionic liquid modified Co-N-C catalyst derived from ZIF-67/C with enhanced catalytic activity for oxygen reduction reaction in alkaline electrolyte

The precursor ZIF-67/xC-T was prepared by solvothermal and pyrolysis methods. A series of ZIF-67/xC-T-yIL catalysts were then prepared by modifying the surface of the precursor with [BMIM][NTf 2 ] ionic liquid . The results showed that [BMIM][NTf 2 ] as sulfur and nitrogen sources, N, S co-doped carbon can improve the catalytic activity of ORR . Meanwhile, [BMIM][NTf 2 ] formed an oxygen-rich layer on the catalyst surface, which increased the contact between oxygen and the active sites, reduced the alkaline strength of the catalyst surface, and improved the desorption ability of the catalyst to the product. Therefore, the ZIF-67/xC-T-yIL catalyst exhibited better ORR activity in an alkaline electrolyte than the catalyst without [BMIM][NTf 2 ]. Among the ZIF-67/xC-T-yIL catalysts, ZIF-67/1.2 C-600–6IL demonstrated the best ORR catalytic activity, with a half-wave potential of 0.86 V and a limiting current density of 5.21 mA cm −2 in 0.1 mol L −1 KOH, which was comparable to that of commercial 20% wt% Pt/C.