Influence of Morphology of Sn Dendrites as Sub-layer on Electrolcatalytic Performance of Sn-Pd Electrocatalysts

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 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. 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.