Synthesis of Pt₃Sn Alloy Nanoparticles and Their Catalysis for Electro-Oxidation of CO and Methanol

Abstract

A lloying a non-noble metal (M) with Pt has become a popular approach to Pt-based catalysts with much reduced Pt usage and enhanced Pt activity. 1À7 Depending on the chemical nature of M, PtM can be made highly active for either electrochemical oxidation or reduction. 5À8 Among various PtM alloys studied thus far, PtSn alloys represent an interesting group of catalysts not only for hydrogenation 9À11 and dehydrogenation reactions, 12À14 but also for electro-oxidation of carbon monoxide (CO), 15À20 methanol, 21À23 ethanol, 23À26 and ethylene glycol. 27 Previous evaluations on single crystals and thin films of Pt 3 Sn for catalytic CO oxidation suggest that Sn as an alloy component can enhance CO oxidation on Pt by promoting H 2 O dissociation on Sn to form SnÀOH and by altering electronic properties of Pt through its bonding with Pt, weakening the CO adsorption on Pt. 15À19 These experimental observations are further supported by the first-principles and density function theory calculations. 8,28 The activation energies for CO oxidation on Pt 3 Sn/Pt (111), Pt 3 Sn (111), and Pt (111) surfaces are 0.64 eV, 0.68, and 0.82 eV, respectively, 28 and water dissociation energy is lower on Sn (0.44 eV) than on Pt (0.67 eV). 8 These studies indicate that PtSn alloys in a nanoparticle (NP) form should be a more promising catalyst for CO and other small organic molecule oxidizations.In this paper, we report a high temperature organic phase synthesis of monodisperse Pt 3 Sn alloy NPs by coreduction of Pt and Sn salts and study their enhanced catalysis for CO and methanol oxidation reaction (MOR) in acid solutions. Previously, Pt 3 Sn NPs were synthesized directly on carbon supports from reduction of the absorbed Pt salt and Sn salt. 20 Recently, Pt 3 Sn NPs were prepared by room temperature H 2 reduction of Pt(dibenzylidene acetone) 2 with (n-Bu) 3 SnH, 29 or made by high temperature coreduction of Pt(acac) 2 (acac = acetylacetonate) and Sn(acac) 2 with 1,2-hexandecanediol. 21

Pt‐Sn‐Eu/C Catalysts: Application of Rare Earth Metals as Anodes in Direct Ethanol Fuel Cells

“…Figure 4b shows the CO oxidation peaks. The literature affirms that Pt-Sn interactions weaken CO adsorption on Pt and promote the dissociation of the water to form Sn-OH ad near Pt-CO ad , facilitating faster CO oxidation [38,39]. The active area of the materials was estimated by integrating the area below the peaks, with the values presented in Table 1.…”

Tailoring Nanoparticle Electrocatalysts for Proton Exchange Membrane Fuel Cells

“…For example, Pt 3 Sn NPs are synthesized through the solutionbased hot-injection and co-reduction of Pt(acac) 2 and Sn(acac) 2 with the size tuned from 4 to 7 nm by controlling injection temperature [61]. For example, Pt 3 Sn NPs are synthesized through the solutionbased hot-injection and co-reduction of Pt(acac) 2 and Sn(acac) 2 with the size tuned from 4 to 7 nm by controlling injection temperature [61].…”

Electrocatalysts and Catalyst Layers for Oxygen Reduction Reaction

“…Pt alloys such as PtePd, 40,41 PteRu, 40,42 PteAu, 20,43e45 PteCo, 26,46e49 PteCr and PteNi, 14,50 PteTi, 51 PteMn, 48 PteFe, 47,48,52 and PteSn, 53 and so on demonstrated some improved catalytic ORR activity when compared to pure Pt because of the synergistic role of the transition metals. It was reported that the catalytic activity of Pt 3 M (M ¼ V, Ti, Co, Fe, Ni) could be significantly improved with strong resistance to poisonous substances.…”