@conference{
author = "Nikolić, Nebojša D. and Lović, Jelena and Ignjatović, Nenad and Dimitrijević, Silvana B.",
year = "2023",
abstract = "Sn-Pd electrocatalysts convenient for a possible application in direct ethanol fuel cell were produced by two electrochemical deposition method. In the first step, Sn dendrites of various degree of ramification were electrodeposited by potentiostatically on cathodic potentials of –1200, –1400, –1600 and –1800 mV vs. Ag/AgCl. Electrodeposition of tin was performed from 20 g/l SnCl2 × 2H2O in 250 g/l NaOH electrolyte [1] at the room temperature on Cu electrodes. In the second step, Pd was electrodeposited galvanostatically at a current density of –5 mA cm-2 on the electrodes with electrodeposited Sn dendrites. Electrodeposition of Pd was performed from 1 M NH4Cl and 0.01 M PdCl2 at the room temperature [2]. The processes of electrochemical deposition of Sn and Pd were performed with amounts of the electricity of 400 and 267 mC, giving an atomic ratio synthesized the electrocatalysts of 60 at.% Sn‒40 at.% Pd. Morpological and elemental analysis of the Sn-Pd electrocatalysts was performed by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. The particle size distribution (PSD) was used to estimate a size of Sn dendrites. The electrocatalytic activity of synthesized Sn-Pd electrocatalysts towards ethanol oxidation reaction (EOR) was examined by cyclic voltammetry (CV) and chronoamperometry, using 1 M NaOH with 1 M ethanol solution. Depending on the applied cathodic potentials, the following shapes of dendrites were formed: the needle-like and the spear-like at –1200 mV, an individual fern-like dendrites at –1400 mV, and intertwined network of dendrites of the fern-like shape was formed at cathodic potentials of – 1600 and – 1800 mV vs. Ag/AgCl. The partial coverage of the Sn dendrites through a formation of compact islands of Pd was attained by electrodeposition of Pd on the electrodes with the Sn dendrites. It was shown that morphology of the Sn dendrites as sub-layer strongly correlates the electrocatalytic activity of the Sn-Pd electrocatalysts. The largest electrocatalytic activity showed the Sn- Pd electrocatalyst constructed from the individual fern-like Sn dendrites as sub-layer produced at a cathodic potential of –1400 mV vs. Ag/AgCl. This dendrite type showed more branchy morphology than those obtained at the other cathodic potentials. Formation of individual needle-like and spear-like dendrites at a cathodic potential of – 1200 mV vs. Ag/AgCl did not contribute significantly to the increase of the initial electrode surface area. On the other hand, due to a high nucleation rate, growth a dendrites from one nucleation centre in more directions, as well as the fact that Sn is very soft metal, morphological characteristics of intertwined Sn dendrites obtained at cathodic potentials of −1600 and −1800 mV vs. Ag/AgCl approached to those of compact massive Sn. The partial coverage of Sn dendrites by Pd can be attributed to the current density distribution effect, because Pd electrodeposition process preferentially perfomed at the higher parts of the surface area, i.e. on the dendrites, rather than on the flat part of the electrode surface area. Aside from an influence of degree of branchy of Sn dendrites as sub-layer on the electrocatalytic activity in ethanol oxidation, varios electrocatalytic performance of the Sn-Pd electrocatalysts can also be ascribed to the bifunctional effect.",
publisher = "Lausanne : International Society of Electrochemistry",
journal = "The 74th Annual Meeting of the International Society of Electrochemistry : Bridging Scientific Disciplines to Address the World’s Challenges 3 to 8 September 2023. Lyon, France",
title = "Influence of Morphology of Sn Dendrites as Sub-layer on Electrolcatalytic Performance of Sn-Pd Electrocatalysts",
url = "https://hdl.handle.net/21.15107/rcub_dais_15643"
}
