Facile synthesis of N/M/O (M= Fe, Co, Ni) doped carbons for oxygen evolution catalysis in acid solution

Doped carbon materials are a good substitute of the platinum-group metal (PGM) catalysts for the oxygen reduction reaction (ORR) in acid fuel cells. The current interest in regenerative fuel cells; or rechargeable metal-air batteries, necessitates the concurrent development of acid-proof, non-PGM catalysts for the oxygen evolution reaction (OER). We present here a facile salt (LiNO3) – activation synthesis of N/M/O (M= Fe, Co, Ni) doped carbons catalysts for use in the highly oxidizing OER reaction environment (low pH solution), using readily accessible starting materials such as citric acid (CA), metal acetate, cyanamide (CM) as the carbon, metal and nitrogen precursors. The effects of LiNO3, CA, heat treatment temperature and the type of metal on the structure, active sites and the OER activity of the catalysts were systematically examined. The results showed that the current densities of N/Fe/O and N/Ni/O doped carbons could be as high as ~9 mA/cm2 at the voltage limit of 1.8 V, while the N/Co/O doped carbon delivered better stability in the acid solution.