Open AccessKinetic Effects of Temperature on Fe–N–C Catalysts for 2e- and 4e-Oxygen Reduction Reactions
Author(s) -
Jie Yang,
Junfen Li,
Ruimin Ding,
Chang Liu,
Xi Yin
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ac1f57
Subject(s) - catalysis , chemistry , selectivity , yield (engineering) , electrolyte , platinum , inorganic chemistry , oxygen , hydrogen peroxide , hydrogen , carbon fibers , metal , electrode , materials science , metallurgy , organic chemistry , composite number , composite material
Hydrogen peroxide (H 2 O 2 ) formed via the two-electron oxygen reduction reaction (2e-ORR) on carbon-based platinum group metal-free (PGM-free) catalysts at elevated temperature can cause catalyst degradation in fuel cells. In this work, we studied the effects of temperature on the selectivity of iron- and nitrogen-doped carbon (Fe–N–C) catalyst for 2e- and 4e-ORR in acidic electrolyte using a high-temperature rotating-ring disk electrode. The results of individual-heating experiments showed that H 2 O 2 yield increased slightly with the increase of temperature. In the meantime, the results of sequential heating/cooling experiments suggested that prolonged high-temperature exposure at ORR polarization conditions can lead to catalyst degradation and higher selectivity for 2e-ORR. The temperature effects on the selectivity of Fe–N–C catalyst for 2e- and 4e-ORR was further explained with a kinetic model describing the competitive reactions and the thermodynamics of the system, which suggested that the increase of H 2 O 2 yield with temperature in the individual-heating experiment was due to the promoted 2e-ORR pathway instead of catalyst degradation.