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Carbon‐Supported, Selenium‐Modified Ruthenium–Molybdenum Catalysts for Oxygen Reduction in Acidic Media

2009; Wiley; Volume: 2; Issue: 7 Linguagem: Inglês

10.1002/cssc.200800215

1864-564X

Maxime J.‐F. Guinel, Arman Bonakdarpour, Biao Wang, Panakkattu K. Babu, F. Ernst, Nagappan Ramaswamy, Sanjeev Mukerjee, Andrzej Więckowski,

Catalytic Processes in Materials Science

Abstract The stability and oxygen reduction activity of two carbon‐supported catalyst materials are reported. The catalysts, Se/Ru and Se/(Ru–Mo), were prepared by using a chemical reduction method. The catalyst nanoparticles were evenly dispersed onto globular amorphous carbon supports, and their average size was ca. 2.4 nm. Thermal treatment at 500 °C for 2 h in an inert argon atmosphere resulted in coarsening of the nanoparticles, and also in some decrease of their activity. A gradual reduction of activity was also observed for Se/Ru during potential‐cycle experiments. However, the incorporation of small amounts of Mo into the Se/Ru catalysts considerably improved the stability of the catalyst against dissolution. The Mo‐containing samples showed excellent oxygen reduction activities even after cycling the potential 1000 times between 0.7 and 0.9 V. Furthermore, they showed excellent fuel‐cell behavior. The performance of the Se/Ru catalysts is greatly improved by the addition of small amounts of elemental Mo. Possible mechanisms responsible for the improvement of the activity are discussed.