Synthesis and Characterization of Ordered Intermetallic Nanostructured PtSn/C and PtSb/C and Evaluation as Electrodes for Alcohol Oxidation

Abstract

Ordered intermetallic compounds of Pt-based metal electrocatalysts have been recently proposed as very efficient anode materials for reactions involved in low temperature fuel cells. In this work, supported ordered intermetallics nanoparticles PtSn/C and PtSb/C and supported platinum nanoparticles (Pt/C) were prepared at low temperature from their metallic precursors by a modified polyol process, using tetraethylene glycol as the solvent and reducing agent and Vulcan carbon XC-72 as the support. Powder X-ray diffraction patterns confirmed the presence of the ordered intermetallic phase and furnished lattice parameters and crystal structure. Transmission electron microscopy images show that the metal particles were highly dispersed and distributed homogeneously over the support, and energy-dispersive X-ray spectroscopy showed that the composition of the final product is within that of the desired stoichiometry. The electrocatalytic activity of these intermetallic phases toward the oxidation of methanol, ethanol, and ethylene glycol were confirmed by cyclic voltammetry and steady-state polarization curve at room temperature. The results showed that the supported intermetallic nanoparticles PtSn and PtSb are more active than the Pt/C catalyst prepared by the same method for alcohol oxidation.

Bifunctional Electrocatalytic Activity of Ordered Intermetallics Based on Pd and Sn

“…The facile complexation of PdCl 4 2– with the positively charged CTAB favors controlled reduction of PdCl 4 2– . Such controlled reduction of the precursors allows the atomic diffusion to be completed during the reaction, leading to formation of intermetallic . Thermal annealing of the product of the solvothermal step in an inert atmosphere is necessary in order to obtain the desired phase-pure intermetallic compound.…”

Pulsed Electrodeposition of Metastable Pd31Bi12 Nanoparticles for Oxygen Reduction Electrocatalysis

“…Nanostructured metastable ordered intermetallic compounds are difficult to rationally synthesize because the nucleation and growth conditions required to access these phases are not unequivocally known. − Literature reports suggest that the formation of metastable ordered intermetallic nanoparticles can occur only under conditions in which interfacial stabilization by capping agents results in greater stability for the metastable phase relative to equilibrium phases or under conditions in which nucleation rather than solid-state diffusion is rate-limiting. ,,− However, the former case is difficult to predict from first-principles, while the latter often results in materials with poor atomic ordering. ,,, Hence, conventional synthetic methods, such as high-temperature annealing and/or colloidal synthesis, largely exclude the formation of metastable ordered intermetallic compounds under typical reaction conditions. ,− Electrochemical deposition has recently emerged as a flexible technique for the direct preparation of metastable alloys and ordered intermetallic phases, yielding materials which can possess high intrinsic catalytic performance. ,, However, these techniques are limited to the preparation of thin films on flat/nonporous substrates, precluding their implementation in application-relevant contexts that require high surface area, and for designing materials that can harness diffusional transport gradients for enhancing catalytic activity and/or selectivity. , …”

Surface‐Roughened Pt‐Decorated Pd Nanoparticles as Efficient Electrocatalysts for Direct Alcohol Fuel Cells

“…In the case of the Pt 4f levels (Figure B), there are three sets of peaks for Pt 4f levels, (72.21 and 75.81 eV), (73.08 and 76.68 eV) and (74.53 and 78.13 eV), corresponding to Pt 0 , Pt 2+ and Pt 4+ in Pd 100– x Pt x /C material . The first set of peaks corresponds to the 4f 7/2 and 4f 5/2 levels of Pt 0 , the second set of peaks corresponds to the 4f 7/2 and 4f 5/2 levels of Pt–O and the third set of peaks corresponds to the 4f 7/2 and 4f 5/2 levels of Pt 4+ .…”