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

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.