CO2 turned into a nitrogen doped carbon catalyst for fuel cells and metal–air battery applications

Abstract

Heteroatom doped metal-free catalysts are one of the most promising replacements for platinum for the alkaline oxygen reduction reaction (ORR). Due to the lack of metal atoms, they are extremely stable and environmentally friendly. However, production of carbon nanomaterials can have a very high CO₂ footprint. In this study, we present ORR catalysts made directly from CO₂via molten salt CO₂ electrolysis. The deposited carbon powder is doped with nitrogen using pyrolysis in the presence of dicyandiamide. The effect of molten carbonate electrolyte composition towards the final ORR activity in 0.1 M KOH is studied. A thorough physico-chemical study of the starting carbons and N-doped catalysts is presented with SEM and TEM imaging, BET analysis, Raman and X-ray photoelectron spectroscopy as well as the rotating disk electrode method. The onset potential and half-wave potential of the better catalyst were −50 and −175 mV vs. SCE in 0.1 M KOH, respectively.