Carbon-supported, selenium-modified ruthenium-molybdenum catalysts for oxygen reduction in acidic media.
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.
Guinel
Maxime J-F
MJ
Department of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7204, USA.
Bonakdarpour
Arman
A
Wang
Biao
B
Babu
Panakkattu K
PK
Ernst
Frank
F
Ramaswamy
Nagappan
N
Mukerjee
Sanjeev
S
Wieckowski
Andrzej
A
D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D004563:Electrochemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D008982:Molybdenum / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D012643:Selenium / Q000737:chemistry*; D014961:X-Ray Diffraction
D002244:Carbon; D012428:Ruthenium; D008982:Molybdenum; D012643:Selenium; D010100:Oxygen