Preparation of Colloidal Nanoparticles of Mixed Metal Oxides Containing Platinum, Ruthenium, Osmium, and Iridium and Their Use as Electrocatalysts

Abstract

The hydrolysis of H 2 PtCl 6 , RuCl 3 , OsCl 3 , and H 2 IrCl 6 under basic conditions in the presence of a watersoluble betaine stabilizer affords aqueous colloidal solutions of the mixed metal oxide PtRuOsIrO x displaying a particle size of 1.3-1.6 nm. The ratio of the four metals can be adjusted by choosing the appropriate relative amounts of metal salts. Characterization was accomplished by TEM, XPS, and XRD. Immobilization of the reduced form on high surface conducting carbon leads to materials which are excellent electrocatalysts showing unusually high resistance to CO poisoning.

Binary Mixtures of Carbon Supported Pt and Ru Catalysts for PEM Fuel Cells

“…Consequently, the development of CO tolerant catalysts is of vital importance in fuel cell research. Various binary and ternary Pt catalyst systems [1][2][3][4][5][6][7] have been tested recently, which show improved activity for the hydrogen oxidation reaction in the presence of CO. In particular, for the binary Pt-Ru system, an enhanced activity has been observed in reformate operation [8,9].…”

Metal Nanoparticles: Applications in Electroanalysis

“…Iridium nanoparticles, which are usually found in the form of iridium oxide, have been synthesized in a variety of ways, either as nanorods [200], as particles using solgels [201], or as colloidal suspensions containing mixed metal oxides [202]. Although several iridium structures have been prepared, their electroanalytical applications to date have primarily been in biosensors, due to their ability to catalytically oxidize and reduce hydrogen peroxide [203][204][205][206].…”

Size‐selective Synthesis of Nanostructured Metal and Metal Oxide Colloids and Their Use as Catalysts

“…In a follow -up study the scope and limitation of the method was defi ned [54,56] . We were particularly interested in fabricating colloidal mixed -metal oxides containing more than two metals.…”

“…Of special interest was the work of Smotkin and Mallouk, who had shown that quaternary alloys composed of Pt, Ru, Os and Ir in the zerovalent form, prepared by other means, are highly active electrocatalysts for potential use in fuel cells [57] . Therefore, we tested our method in the preparation of a mixed metal oxide containing these four metals [56] . The hydrolysis of an aqueous mixture of H 2 PtCl 6 , RuCl 3 , OsCl 3 and H 2 IrCl 6 under basic conditions in the presence of the stabilizing surfactant 11 afforded aqueous colloidal solutions of the mixed metal oxide PtRuOsIrO x displaying a particle size of 1.3 -1.6 nm [56] .…”