Preparation of N, S doped Co-Fe/C catalyst derived from ZIF-67/ionic liquid and its catalytic activity for oxygen reduction reaction in alkaline electrolyte

ZIF-67(CoFe) was synthesized using the solvothermal method , and the precursor of ZIF-67(CoFe)/xC-yIL was obtained by grinding the mixture of ZIF-67(CoFe), [BMIM][NTf 2 ] ionic liquid (IL), and carbon black. A series of ZIF-67(CoFe)/xC-yIL-T catalysts were prepared by calcining the precursor at different temperatures. The structure of the catalysts was examined using XRD , TEM, BET and XPS analysis. The results show that the high-temperature treatment of the precursor contributes to the formation of the structure of the N, S-co-doped carbon-coated nanoparticles . The introduction of ionic liquid increases the specific surface area of the catalysts and exposes more active sites. At the same time, as a sulfur source, ionic liquid forms a C-S bond, which is conducive to improving ORR activity. The optimal ORR half-wave potential and limited current density of ZIF-67(CoFe)/1.5 C-45IL-600 are 0.87 V vs. RHE and 4.64 mA cm -2 , respectively, in 0.1 mol L −1 KOH.