Electrochemical and in situ FTIR study of the ethanol oxidation reaction on PtMo/C nanomaterials in alkaline media

In this work, the catalytic activity of PtMo/C catalysts for the Ethanol Oxidation Reaction (EOR) in 0.5 mol L-1 KOH electrolyte was evaluated by electrochemical and in situ Fourier Transform Infrared Spectroscopy (FTIR) measurements. The alloys having 1:1, 2:1 and 3:1 Pt:Mo atomic ratios were synthesized by the formic acid method. X-ray diffraction analyses (XRD) showed the crystalline features of the catalysts, with crystallite sizes between 2.5 and 3.2 nm. Cyclic voltammograms (CVs) indicated the alloys mass catalytic activity in the order: Pt1Mo1/C > Pt3Mo1/C > Pt2Mo1/C, in all cases higher that Pt/C. For specific catalytic activity, the performance was in the order Pt3Mo1/C > Pt1Mo1/CPt/C > Pt2Mo1/C. Two CO-like species namely COadsII and COadsII were evidenced from CO-stripping measurements on the alloys. In situ FTIR characterization showed that the alloys promote the oxidation of ethanol in the alkaline media mainly through a 4 electrons transfer route. CO2 was produced probably from the break-up of the C-C bond and the oxidation of C1 species. Pt3Mo1/C produced mores COadsI, followed by Pt1Mo1/C, oxidizing carbon monoxide more easily. These two alloys also had a higher CO2/CH3CHO ratio, due to a high efficiency for oxidizing C-2 and C1 species to CO2. Such capabilities promoted a higher catalytic activity of Pt1Mo1/C and Pt3Mo1/C for the EOR, related to the other catalysts. (C) 2016 Elsevier B.V.All rights reserved.