Electrochemical and spectroscopic characterization of a dicobalt macrocyclic Pacman complex in the catalysis of the oxygen reduction reaction in acid media
2013 (English)In: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, E-ISSN 1099-1409, Vol. 17, no 4, 252-258 p.Article in journal (Refereed) Published
The dicobalt complex [Co-2(L-2)] of a Schiff-base pyrrole macrocycle adopts a Pacman structure in solution and the solid state and shows much greater catalytic activity and selectivity for the four-electron oxygen reduction reaction (ORR) than the mononuclear cobalt phthalocyanine (CoPc) counterpart. Soft X-ray absorption spectroscopy (XAS) shows that the Co center in Co-2(L-2) is of the same valence as mononuclear CoPc. However, the former complex shows higher unoccupied Co 3d density which is believed to be beneficial for electron transfers. Furthermore, the XAS data suggests that the crystal fields for Co-2(L-2) and CoPc are different, and that an interaction remains between two Co atoms in Co-2(L-2). DFT calculations imply that the sterically hindered, cofacial structure of the dicobalt complex is critical for the operation of the four-electron reaction pathway during the ORR.
Place, publisher, year, edition, pages
2013. Vol. 17, no 4, 252-258 p.
dicobalt macrocyclic complex, oxygen reduction reaction, X-ray absorption spectroscopy, fuel cells
Other Chemistry Topics
IdentifiersURN: urn:nbn:se:kth:diva-124732DOI: 10.1142/S1088424612501490ISI: 000320618600002ScopusID: 2-s2.0-84879410742OAI: oai:DiVA.org:kth-124732DiVA: diva2:638413
QC 201307302013-07-302013-07-292013-07-30Bibliographically approved