Ethanol electro-oxidation on carbon-supported Pt1Mn3 catalyst investigated by pinhole on-line electrochemical mass spectrometry

Abstract

• Pt/C and Pt 1 Mn 3 /C catalysts are synthesized by impregnation method using NaBH 4 . • The electro-oxidation behavior of the ethanol on the catalysts is considered by using electrochemical mass spectrometry. • The CO 2 current efficiencies are calculated. • The binary catalyst is more active than the Pt-only catalyst. Carbon supported Pt and Pt 1 Mn 3 (20 wt%) electrocatalysts were synthesized by impregnation method using NaBH 4 as a reducing agent. The catalysts were physically characterized by X-Ray Diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES) and Transmission Electron Microscopy (TEM). The electrocatalytic activity of the prepared electrocatalysts for the ethanol oxidation reaction (EOR) were investigated by potentiodynamic and potentiostatic measurements with POEMS (Pinhole On-line Electrochemical Mass Spectrometry) that allow the detection of volatile intermediates/products of the EOR. The potentiodynamic and potentiostatic results show that, although kinetics of the reaction is faster on Pt/C, Pt 1 Mn 3 /C electrocatalyst exhibit higher ethanol oxidation efficiency, and, incomplete ethanol oxidation reaction to acetaldehyde and acetic acid prevails under the conditions selected in this study for two electrocatalysts. After calibration of the m / z = 44 mass signal, the CO 2 current efficiencies (CCEs) were calculated on the synthesized electrocatalysts: the CCE value reach up to ∼9% on Pt 1 Mn 3 /C at 25 °C compared to ca. ∼7% on Pt/C, which identifies that the addition of Mn enhances the oxidation of CO to CO 2 .