Electrocatalysts for ethanol and ethylene glycol oxidation reactions. Part II: Effects of the polyol synthesis conditions on the characteristics and catalytic activity of Pt–Ru/C anodes

• Pt–Ru/C catalysts synthesized by a polyol/alcohol/water process.
• Formation of oxides regardless of the presence or absence of water during synthesis.
• The anodes have been evaluated for the EOR and the EGOR.
• The Pt–Ru/C catalysts showed higher catalytic activity than Pt/C.
• Higher catalytic activity of Pt–Ru/C alloys synthesized with H2O demonstrated.

This paper presents a continuation about the effects of polyol synthesis conditions on the physicochemical and electrocatalytic characteristics of Pt-based alloys. Pt–Ru/C alloys with nominal Pt:Ru atomic ratio of 1:1 were synthesized by a polyol process with different ethylene glycol:ethanol:water volume ratios. The Pt–Ru/C catalysts were tested as anodes for the Ethanol and the Ethylene Glycol Oxidation Reactions. X-ray diffraction showed that the Pt–Ru/C catalysts have low crystallinity, which limited the analysis of some important factors such as average particle size, degree of alloying and lattice parameter. Such structural feature was attributed to a very small particle size, as confirmed by TEM analysis. The chemical composition by EDS indicated that the Pt:Ru 1:1 ratio can be achieved under most of the synthesis conditions. Moreover, the formation of oxides was a constant characteristic, whether water was present or absent during the synthesis. The electrochemical characterization showed that the synthesis conditions have an important effect on the electrocatalytic activity of the Pt–Ru/C alloys for both oxidation reactions. Compared to a Pt/C catalyst, all of the alloys showed lower onset potentials for the oxidation reactions, but several of them delivered smaller oxidation current densities.

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