Study on ethanol electro-oxidation over a carbon-supported Pt-Cu alloy catalyst by pinhole on-line electrochemical mass spectrometry

A carbon supported Pt-Cu electrocatalyst was synthesized by the microwave-polyol method following acid-treatment and physically characterized by different techniques including X-ray diffraction (XRD) and transmission electron microscopy (TEM). Both potentiodynamic and potentiostatic measurements with pinhole on-line electrochemical mass spectrometry were carried out to study the electrocatalytic activity and reaction intermediates of Pt/C and Pt-Cu/C electrocatalysts during the ethanol oxidation reaction. The results of potentiodynamic and potentiostatic measurements showed that the Pt-Cu/C electrocatalyst has higher ethanol oxidation efficiency and incomplete ethanol oxidation to acetaldehyde and acetic acid prevails under the given conditions. After calibration of the m/z = 44 mass signal, the CO2 current efficiencies on Pt/C and PtCu-3/C were similar to 7% and similar to 12%, respectively, which reveal that the presence of copper enhances the complete ethanol oxidation to CO2.