Synthesis of PtSn nanostructured catalysts supported over TiO2 and Ce-doped TiO2 particles for the electro-oxidation of ethanol

Abstract

PtSn/TiO2 and PtSn/Ce-doped TiO2 catalysts were synthesized and evaluated for ethanol electro-oxidation in acid media. Titanium dioxide and Ce-doped TiO2 nanoparticles were prepared by hydrothermal method followed by calcination at 923 K. Bimetallic PtSn catalysts supported on the oxide materials were synthesized by microwave assisted reduction in ethylene glycol (EG). The structural properties of the resulting materials were evaluated via TEM and XRD, and the compositions were assessed by EDX and ICP-AES analysis. PtSn nanoparticles of about 3-4 nm were deposited on TiO2 and Ce-TiO2 particles. It was found that the catalyst composition is scarcely influenced by the cerium content in the mixed oxides while the electrochemical surface area per unit mass decreases upon the incorporation of Ce in the anatase lattice. The electrochemical tests pointed out that the electrocatalytic activity for ethanol oxidation decreases markedly as the Ce content increases. The results indicate that the presence of cerium in the titanium dioxide crystalline network induces local structural and electronic modifications, thereby leading to a reduction of the crystallinity, surface conductivity and the amount of OH species adsorbed on the surface of the oxide support.