Fe-containing polyimide-based high-performance ORR catalysts in acidic medium: a kinetic approach to study the durability of catalysts. Issue 1 (24th September 2014)

• Record Type: Journal Article
• Authors: Muthukrishnan, Azhagumuthu; Nabae, Yuta; Hayakawa, Teruaki; Okajima, Takeyoshi; Ohsaka, Takeo
• Is Part Of: Catalysis science & technology. Volume 5:Issue 1(2015:Jan.)
• Page Start: 475
• Page End: 483
• Publication Date: 2014-09-24
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/c4cy01001a
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : The ORR activity and durability of Fe-containing non-precious N-doped carbon catalysts in acidic medium were studied using a rotating ring-disk electrode voltammetry and XPS technique. Abstract : The ORR activity and durability of Fe-containing non-precious N-doped carbon catalysts in acidic medium were studied using a rotating ring-disk electrode voltammetry and XPS technique. The catalysts (Fe/PI) were synthesised from the pyrolysis of the Fe(acac)3 and polyimide nanoparticle (PI) mixture. The catalytic activity and durability of Fe/PI are superior to that of the conventional phthalocyanine-based catalyst. The onset potential of ORR was 0.915 V vs. RHE in 0.5 M H2 SO4 which is very close to that of a commercially available Pt/C catalyst. The Fe/PI catalyst sustains its activity and stability even after 11 110 repeating potential steps between 0.6 and 1.0 V vs. RHE in O2 -saturated 0.5 M H2 SO4 and 1110 potential cycles between 1.0 and 1.5 V vs. RHE in argon-saturated 0.5 M H2 SO4, respectively. The kinetic and mechanistic analyses of the ORR on this catalyst indicate that the ORR, as a whole, follows a 4-electron (parallel) pathway. The N 1s XPS spectra before and after the durability test indicate that pyridinic and graphite-like nitrogens take part in improving the ORR activity, whereas nitrogen oxides have a negative role in the ORR. The loss of ORR activity was observed after the acid washing of the catalysts, which suggests the role of Fe in the overall 4-electron reduction of O2 .