Platinum nanoparticles embedded in pyrolyzed nitrogen-containing cobalt complexes for high methanol-tolerant oxygen reduction activity
Journal
Journal of Materials Chemistry
Journal Volume
20
Journal Issue
35
Pages
7551-7557
Date Issued
2010
Author(s)
Wang, C.-H.
Hsu, H.-C.
Chang, S.-T.
Du, H.-Y.
Chen, C.-P.
Wu, J.C.-S.
Shih, H.-C.
Abstract
High oxygen reduction activity of methanol-tolerant catalysts was successfully reported using platinum nanoparticles embedded in cobalt-based nitrogen-containing complexes supported on carbon blacks (Pt–N-complex/C). The oxygen reduction reaction (ORR) of the Pt–N-complex/C was attributed to four-electron transfer pathway in which oxygen was directly reduced to water, yielding four electrons. In a methanol-containing solution, the platinum intrinsically favors the methanol oxidation reaction over the ORR, which is a major drawback for direct methanol fuel cells (DMFCs). In comparison, when the Pt–N-complex/C is introduced in a methanol-containing solution, not only is the methanol oxidation suppressed but also the four-electron-transfer in the ORR is maintained up to the diffusion-limiting region. Physicochemical characterization of the Pt–N-complex/C indicates that pyrrolic N-type poly-aromatic hydrocarbons were formed in a network structure around the catalysts and prevented them from the methanol oxidation reaction. In a DMFC test at elevated methanol concentrations, the one with the Pt–N-complex/C cathode showed superior stability over the one with the Pt-based cathode, which may offer a solution to the methanol crossover problem in DMFCs.
SDGs
Publisher
Royal Society of Chemistry
Type
journal article