Pulse electrodeposited PtSn electrocatalyst on a PEDOT/graphene-based electrode for ethanol oxidation in an acidic medium

Abstract

Pulse electrodeposition of Pt and Sn using 10 mM H2PtCl6⋅6H2O in 0.10 M H2SO4 and 10 mM SnCl2⋅2H2O in 0.10 M HCl was conducted on a support matrix consisting of electropolymerized poly (3,4-ethylenedioxythiophene) (PEDOT) and electrochemically exfoliated graphene oxide (EGO). The Field Emission – Scanning Electron Microscopy (FE-SEM) studies of PtSn/PEDOT/EGO (i.e., PEDOT on EGO) showed a homogeneous globular composite, while PtSn/EGO/PEDOT (i.e., EGO on PEDOT) revealed a heterogeneous composite with wrinkled and globular surface morphologies. An Energy Dispersive X-ray (EDX) analysis (as a percentage of Pt and Sn) of PtSn/PEDOT/EGO is in agreement with the X-ray Photoelectron Spectroscopy (XPS) analysis, indicative of a homogeneous surface for the dispersion of metallic particles. However, the EDX and XPS analyses of PtSn/EGO/PEDOT showed variations in the amount of Pt and Sn, indicative of possible mixing of the EGO and PEDOT support matrices. Cyclic voltammetry (CV) and chronoamperometry using 1.0 M ethanol in 0.1 M H2SO4 demonstrated higher electrocatalytic activity (83.7 mA/cm2) and electrochemical stability (29.0% current retention) in PtSn/PEDOT/EGO than PtSn/EGO/PEDOT.