Nanostructured Hybrid Electrocatalytic Materials for Ethanol Oxidation: Activation of Pt-Ru Centers through Modification with Selected Metal Oxides

Ethanol is a biofuel of potential importance to the technology of low-temperature polymer-membrane fuel cells. The alcohol can be ideally oxidized to carbon dioxide thus delivering 12 electrons. But realistically the reaction is rather slow and complex at ambient conditions. Obviously, there is a need to develop novel electrocatalytic materials. In the present work we have utilized as carriers (matrices) carbon nanotubes (CNTs) modified with nanostructured titanium dioxide. TiO2 can be considered as model robust transition metal oxide that, by analogy to tungsten oxide or zirconium oxide (also considered here), is capable of generating of interfacial reactive hydroxy groups on the surfaces. By dispersing bimetallic platinum-ruthenium catalytic nanocenters over the CNT-supported TiO2, the electrocatalytic activity of Pt-Ru nanoparticles towards oxidation of ethanol has been enhanced. Remarkable increases of electrocatalytic currents measured under voltammetric and chronoamperometric conditions have been observed. Electrochemical diagnostic experiments have been supported with microscopic monitoring of morphology using transmission electron microscopy (TEM). In addition to the presence of active interfacial hydroxyl groups, an important issue is the improvement of overall conductivity titanium dioxide - due to the presence of dispersed carbon nanotubes. Comparative measurements aimed at investigation of the presence of dispersed nanostructured metal oxides on dynamics of the oxidation of different fuels (here formic acid).