A Pt-based electrocatalyst for direct fuel cells, Pt3Ti, has been prepared in the form of nanoparticles. Pt(1,5-cyclooctadiene)Cl2 and Ti(tetrahydrofuran)2Cl4 are reduced by sodium naphthalide in tetrahydrofuran to form atomically disordered Pt3Ti nanoparticles (FCC-type structure: Fm3m; a = 0.39 nm; particle size = 3 +/- 0.4 nm). These atomically disordered Pt3Ti nanoparticles are transformed to larger atomically ordered Pt3Ti nanoparticles (Cu3Au-type structure: Pm3m; a = 0.3898 nm; particle size = 37 +/- 23 nm) by annealing above 400 degrees C. Both atomically disordered and ordered Pt3Ti nanoparticles show lower onset potentials for the oxidation of formic acid and methanol than either pure Pt or Pt-Ru nanoparticles. Both atomically disordered and ordered Pt3Ti nanoparticles show a much lower affinity for CO adsorption than either pure Pt or Pt-Ru nanoparticles. Atomically ordered Pt3Ti nanoparticles show higher oxidation current densities for both formic acid and methanol than pure Pt, Pt-Ru, or atomically disordered Pt3Ti nanoparticles. Pt3Ti nanoparticles, in particular the atomically ordered materials, have promise as anode catalysts for direct fuel cells.

The average domain size determined from pXRD is 10 nm. The particles have been characterized by pXRD, SEM, STEM, EDX, and CBED. SEM and STEM images show the particles to be aggregated, forming clusters and chains. The BET surface area of the nanoparticles was measured using Kr as the adsorbing gas. The electrocatalytic oxidation of formic acid and methanol by the as-prepared PtPb and PtBi nanoparticles has been studied by rotating disk voltammetry for potential fuel-cell applications. The PtPb and PtBi nanoparticles displayed enhanced electrochemical activity toward formic acid and methanol oxidation when compared to commercially available Pt and PtRu nanoparticles. The electrocatalytic activity of the PtPb nanoparticles was studied as a function of sonication time of the catalyst ink, and morphology changes were followed by scanning electron microscopy. The results showed that the activity of the catalyst initially increased with sonication time and then decreased.

The electrode reaction of the molecular oxygen (O 2 )/superoxide ion (O 2 Ϫ) redox couple at glassy carbon ͑GC͒, gold ͑Au͒, and platinum ͑Pt͒ electrodes in three 1-n-alkyl-3-methylimidazolium tetrafluoroborate (AMIBF 4 ) room-temperature ionic liquids ͑RTILs͒, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-n-propyl-3-methylimidazolium tetrafluoroborate, and 1-n-butyl-3methylimidazolium tetrafluoroborate, has been analyzed quantitatively using cyclic voltammetry, normal pulse voltammetry, and hydrodynamic chronocoulometry ͑HCC͒. Cyclic voltammetric measurements showed that the redox reaction of the O 2 /O 2 Ϫ couple in these RTILs is a quasi-reversible process and that the resulting O 2 Ϫ is stable. The relevant thermodynamic and kinetic parameters ͓the formal potential (E 0 Ј), the standard rate constant (k 0 ), and the cathodic transfer coefficient (␣ c )] of the O 2 /O 2 Ϫ redox couple were evaluated using cyclic and normal pulse voltammetry: ͑i͒ the E 0 Ј values are almost the same irrespective of the media and electrode materials examined, i.e., ca. Ϫ1.0 V vs. an internal standard potential of the ferrocene ͑Fc͒/ferricinium ion (Fc ϩ ) redox couple, ͑ii͒ the k 0 value is dependent on the electrode material and increases in the order k 0 (Pt) Ͻ k 0 (Au) Ͻ k 0 (GC), and ͑iii͒ the values of ␣ c are in the range of 0.35-0.47. The diffusion coefficients (D O 2 ) and saturated concentrations (C O 2 ) of O 2 in three AMIBF 4 RTILs were also determined by HCC.