Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6606171 | Electrochimica Acta | 2016 | 36 Pages |
Abstract
The electrochemical behaviors of a tris(2-pyridylmethyl)amine copper complex (Cu-tmpa) in aqueous buffer solutions were examined. Acid-base and redox equilibria were clarified using cyclic voltammetry and ESR spectra. The pKa values of both CuII-tmpa and CuI-tmpa were determined based on the pH-E°Ⲡdiagram of Cu-tmpa. The slopes in the diagram strongly suggest the presence of hydroxo-bridged dimer complexes of CuII-tmpa. This notion is supported by ESR spectra. The oxygen reduction reaction (ORR) by Cu-tmpa was also examined over a wide range of pHs. The ORR current of Cu-tmpa decreased significantly above pH 12.0. This pH value coincides with the pKa value of CuI-tmpa. The decrease in ORR current in basic solution is attributed to the formation of a hydroxo complex of CuI. These findings are important for the application of Cu complexes as cathodes in fuel cells.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Masafumi Asahi, Shin-ichi Yamazaki, Shinobu Itoh, Tsutomu Ioroi,