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Spatially resolved quantification of ruthenium oxide phase in a direct methanol fuel cell operated under normal and fuel starved conditions

Title data

Dixon, D. ; Schökel, Alexander ; Roth, Christina:
Spatially resolved quantification of ruthenium oxide phase in a direct methanol fuel cell operated under normal and fuel starved conditions.
In: Electrochimica Acta. Vol. 298 (2019) . - pp. 52-58.
ISSN 0013-4686
DOI: https://doi.org/10.1016/j.electacta.2018.12.073

Abstract in another language

In operando Ru K edge X-ray absorption spectra were recorded at various cell voltages from specific regions of a direct methanol fuel cell (DMFC), such as methanol inlet, outlet and middle regions. From the linear combination fitting analysis, it was found that 50% of the Ru in the pristine Pt/Ru catalyst is in an oxidized form that matches with hydrated ruthenium oxide (RuO2·xH2O). During the DMFC cycling, fraction of this oxide phase gets reduced and forms metallic Ru. Furthermore, it is observed that under normal DMFC operation at various cell voltages relatively a higher amount of RuO2 phase is present at the methanol inlet compared to the methanol outlet. This difference in the amount of RuO2 phase observed translates into inhomogeneous distribution of potential/current within a single cell. The amount of RuO2 phase increased further when the DMFC was subjected to fuel starvation conditions (very high anode potential). Again compared to the methanol outlet region, a higher amount of RuO2 phase was found at the methanol inlet. As RuO2 is more prone to dissolution compared to metallic Ru, it can be concluded that methanol inlet region is more prone to Ru dissolution compared to methanol outlet region.

Further data

Item Type: Article in a journal
Refereed: Yes
Keywords: X-ray absorption; In operando; DMFC; Anode; Fuel starvation
Institutions of the University: Faculties > Faculty of Engineering Science > Chair Electrochemical Process Engineering > Chair Electrochemical Process Engineering - Univ.-Prof. Dr. Christina Roth
Faculties
Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Chair Electrochemical Process Engineering
Result of work at the UBT: No
DDC Subjects: 500 Science > 540 Chemistry
600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 28 Apr 2021 10:14
Last Modified: 30 May 2022 13:43
URI: https://eref.uni-bayreuth.de/id/eprint/64965