(544gj) Combustion Synthesis of Ptzn Nanoparticle Electrocatalysts for Ethanol Oxidation in Alkaline Medium

Kumar, A., Qatar University
Matin, M. A., Qatar University
In this work, we report the syntheses of Zn-enriched PtZn nanoparticle (NP) electrocatalysts for ethanol oxidation reaction (EOR). The syntheses of Zn-enriched-Pt NPs are achieved by solution combustion synthesis (SCS) with the reaction reagents of Pt(NO3)2 solution, Zn(NO3)2 6H2O and glycine in H2O where glycine is used as a fuel. In SCS, the glycine-amount is varied with a fixed stoichiometric ratio of Pt- and Zn-precursors at 1: 1 for two electrocatalysts (PtZn/C) of fuel-high (PtZn/C (1.75)) and fuel-low (PdZn/C (0.5)). The analytical techniques of X-ray diffractometry, transmission electron microscopy and scanning electron microscopy are used for the crystallite size, particle distribution and elemental composition of the electrocatalysts, respectively. High angle annular dark field-scanning transmission electron microscopy attached to energy dispersive X-ray spectroscopy was conducted for mapping the elemental distribution in PtZn/C (1.75) NPs showing NPs composed of Pt and Zn alloys. The electronic structure of elements in PtZn/C samples analyzed by X-ray photoelectron spectroscopy shows electronic interaction between Zn and Pt. The cyclic voltammetry is applied for the electrocatalysis of C2H5OH in an alkaline medium (1M KOH). The cyclic voltammetric results on PtZn/C NPs show that PtZn/C system has improved electrocatalytic activity by a factor of ~2.2-2.3 in comparison with commercial Pt/C. The onset potential of EOR on PtZn/C is earlier than that of Pt/C. The stability test conducted by chronoaperometry on PtZn/C and Pt/C shows higher stability on PtZn/C than Pt/C. The crystallite sizes, the electronic structure and the electrochemical properties in PtZn/C samples are affected by the variation in fuel amount.