Methanol dehydrogenation reaction at Au@Pt catalysts: Insight into the methanol electrooxidation

The electrochemical methanol oxidation reaction (MOR) has received considerable attention because of its importance in the development of fuel cells. Recently, bimetallic Au-Pt catalyst systems were developed as efficient MOR electrocatalysts. In this work, we investigated the methanol dehydrogenation reaction (MDHR, CH3OH -> CO + 2H(2)) on the Au@Pt core-shell surfaces using an in situ surface-enhanced Raman spectroscopy (SERS) technique. The CO intermediates produced by the MDHR and adsorbed on the Pt surfaces play an important role in the electrochemical MOR. The formation of CO on Au@Pt surfaces during the MDHR was examined as a function of the coverage and thickness of the Pt layers on Au. The effect of the electrode potential applied to the Au@Pt surface on the MDHR behavior was also investigated. The SERS results regarding the MDHR behaviors on the different Pt layers on Au surfaces could provide rational comparisons of the electrochemical MOR activities of the Au@Pt and Pt/C catalysts that can be evaluated differently depending on the contact time between the electrode and methanol and the scan rate. The present work provides insight into the electrocatalytic activity of bimetallic core-shell catalysts from the mechanistic perspective. (C) 2018 Elsevier Ltd. All rights reserved.