| Full text | |
| Author(s): |
Castanheira, Luis
[1, 2]
;
Silva, Wanderson O.
[3]
;
Lima, Fabio H. B.
[3]
;
Crisci, Alexandre
[4, 5]
;
Dubau, Laetitia
[1, 2]
;
Maillard, Frederic
[1, 2]
Total Authors: 6
|
| Affiliation: | [1] Univ Grenoble Alpes, LEPMI, F-38000 Grenoble - France
[2] CNRS, LEPMI, F-38000 Grenoble - France
[3] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil
[4] Univ Grenoble Alpes, SIMAP, F-38000 Grenoble - France
[5] CNRS, SIMAP, F-38000 Grenoble - France
Total Affiliations: 5
|
| Document type: | Journal article |
| Source: | ACS CATALYSIS; v. 5, n. 4, p. 2184-2194, APR 2015. |
| Web of Science Citations: | 103 |
| Abstract | |
The impact of the carbon structure, the aging protocol, and the gas atmosphere on the degradation of Pt/C electrocatalysts were studied by electrochemical and spectroscopic methods. Pt nanocrystallites loaded onto high-surface area carbon (HSAC), Vulcan XC72, or reinforced-graphite (RG) with identical Pt weight fraction (40 wt %) were submitted to two accelerated stress test (AST) protocols from the Fuel Cell Commercialization Conference of Japan (FCCJ) mimicking load-cycling or start-up/shutdown events in a proton-exchange membrane fuel cell (PEMFC). The load-cycling protocol essentially caused dissolution/redeposition and migration/aggregation/coalescence of the Pt nanocrystallites but led to similar electrochemically active surface area (ECSA) losses for the three Pt/C electrocatalysts. This suggests that the nature of the carbon support plays a minor role in the potential range 0.60 < E < 1.0 V versus RHE. In contrast, the carbon support was strongly corroded under the start-up/shutdown protocol (1.0 < E < 1.5 V versus RHE), resulting in pronounced detachment of the Pt nanocrystallites and massive ECSA losses. Raman spectroscopy and differential electrochemical mass spectrometry were used to shed light on the underlying corrosion mechanisms of structurally ordered and disordered carbon supports in this potential region. Although for Pt/HSAC the start-up/shutdown protocol resulted into preferential oxidation of the more disorganized domains of the carbon support, new structural defects were generated at quasi-graphitic crystallites for Pt/RG. Pt/Vulcan represented an intermediate case. Finally, we show that oxygen affects the surface chemistry of the carbon supports but negligibly influences the ECSA losses for both aging protocols. (AU) | |
| FAPESP's process: | 11/50727-9 - Development of systems for hydrogen production and for the generation and utilization of electrochemical energy |
| Grantee: | Ernesto Rafael Gonzalez |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 13/16930-7 - Electrocatalysis V: electrocatalytic processes of chemical and electrical energy interconversion |
| Grantee: | Edson Antonio Ticianelli |
| Support Opportunities: | Research Projects - Thematic Grants |