Synthesis and Characterization of a Pt₃Ru₁/Vulcan Carbon Powder Nanocomposite and Reactivity as a Methanol Electrooxidation Catalyst

Thermal treatment of [Ru(2,3-bis(2-pyridyl)quinoxaline)₃(PtCl₂)₃](BF₄)₂/Vulcan carbon powder composites under reactive conditions forms Pt−Ru/carbon nanocomposites containing 27−34 wt % metal alloy as highly dispersed nanoparticles of ca. Pt₇₅Ru₂₅ stoichiometry. The metal nanoparticles have an average diameter of 6 nm (by TEM) and an fcc unit cell of lattice constant 3.907 (9) Å, as expected for Pt-rich Pt−Ru alloys. On-particle HR-EDS analysis indicates that gross phase separation of Pt and Ru does not occur on the nanoparticle scale. Evaluation of the performance of this nanocomposite as a methanol electrooxidation catalyst in a direct methanol fuel cell and in an electrochemical cell designed for combinatorial testing is reported.