Synthesis and Characterization of Os and Pt−Os/Carbon Nanocomposites and their Relative Performance as Methanol Electrooxidation Catalysts

• Published in: Chemistry of materials Vol. 15; no. 5; pp. 1119 - 1124
• Main Authors: Moore, Joshua T, Chu, Deryn, Jiang, Rongzhong, Deluga, Gregg A, Lukehart, C. M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 11.03.2003
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Osmium Alloys; Transition metal; Carbon; X ray diffraction; Osmium; Primary alcohol; Surface structure; Electrocatalysis; Thermodynamics; Transmission electron microscopy; Morphology; Nanocomposite; Oxidation; Platinum Alloys; Electrochemical reaction; Nanostructured materials; Fuel cell; Organic compounds; Binary alloy; Methanol
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm011565c

Thermal treatment of cis-(2,2‘-bipyridine)2OsCl2, (η6-cymene)2Os2Cl4, or [(bpy)2Os(μ-bpm)PtCl2][CF3SO3]2/Vulcan carbon powder composites under solely reductive conditions affords Os or Pt−Os/carbon nanocomposites consisting of metal nanoparticles highly dispersed on the carbon support. Nanocomposites containing ca. 35−50 wt % metal with metal nanocrystals of ca. 5−6 nm average diameter are formed. Evaluation of the performance of these nanocomposites as methanol electrooxidation catalysts in direct methanol fuel cells and in an electrochemical cell designed for combinatorial testing reveals that, although the Os/carbon nanocomposites and the Pt−Os alloy/carbon nanocomposite give open circuit potentials indicative of thermodynamically favorable methanol oxidation, the kinetics of these oxidations are too low to be of practical importance. Unfortunately, the Os-containing electrocatalysts prepared by this synthesis strategy did not exhibit high performance for methanol oxidations as predicted by theoretical computations.