High Performance Pt Nanocatalysts for the Oxidation of Methanol and Ethanol in Acid Media by Effect of Functionalizing Carbon Supports with Ru Organometallic Compounds

Abstract

The Intermittent Microwave Heating (IMH) assisted polyol method was used to disperse Pt nanoparticles on Vulcan XC-72 (C) and reduced Graphene Oxide (rGO) functionalized with [(η 6-C6H5OCH2CH2OH)RuCl2]2 (Ru-dim) and [(η 6-C6H4(CHMe2)Me)RuCl2]2 (Ru-cym). The nanocatalysts were labeled as Pt/CRu-dim, Pt/CRu-cym, Pt/rGORu-dim and Pt/rGORu-cym. Their catalytic activity was evaluated for the Methanol (MOR) and Ethanol Oxidation Reactions (EOR). 1H and APT 13C NMR characterization showed the coordination of arene ligands with ruthenium atoms, supporting the formation of Ru-dim and Ru-cym. Raman spectroscopy indicated that C and rGO preserve their graphitic band structure after functionalization. Functionalization of the supports resulted in the development of several surface chemical groups. The electrochemical characterization showed that: i) Pt/CRu-dim was the nanocatalyst with the highest catalytic activity for the MOR, demonstrating also a high performance for the EOR; ii) Pt/rGORu-cym showed a good electrocatalytic behavior for both reactions at more negative potentials, nevertheless delivering lower current densities (j). In terms of the organic molecule, higher j values have been obtained from the MOR, compared to the EOR. The results showed that these nanocatalysts can be considered as anode materials in Direct Alcohol Fuel Cells applications.