Indexed on: 05 Jan '20Published on: 04 Jan '20Published in: Inorganic Chemistry
The rational design of electronically tuned transition-metal-doped conductive carbon nanostructures has emerged as a potential substitution of a platinum-group-metal (PGM)-free electrocatalyst for oxygen reduction reaction (ORR). We report here a universal strategy using a one-step thermal polymerization reaction for transition-metal-doped graphitic carbon nitride (g-CN) without any conductive carbon support as a highly efficient ORR electrocatalyst. X-ray absorption spectroscopy evidences the presence of Fe-N active sites with a possible three-coordinated Fe atom with N atoms. The as-prepared Fe-g-CN with improved surface area, graphitic nature, and conductive carbon framework exhibits a superior electrochemical performance toward ORR activity in an alkaline medium. Interestingly, it displays a 0.88 V (vs reversible hydrogen electrode, RHE) half-wave potential () with a four-electron-transfer pathway and excellent stability outperforming platinum/carbon (Pt/C) in an alkaline medium. More impressively, when the Fe-g-CN catalyst is used as a cathode material in a zinc-air battery, it presents a higher peak power density (148 mW cm) than Pt/C (133 mW cm), which further established the importance of the low-cost material synthesis approach toward the development of an earth-abundant PGM-free catalyst for fuel-cell and air battery fabrication.