Facile Aqueous-Phase Synthesis of the PtAu/Bi2O3 Hybrid Catalyst for Efficient Electro-Oxidation of Ethanol.

In this work, we present a facile aqueous-phase synthesis of a hybrid catalyst consisting of PtAu alloy supported on Bi2O3 microspheres. Multistep reduction of HAuCl4 and K2PtCl4 salts on Bi2O3 and subsequent annealing lead to the formation of this hybrid catalyst. To the best of our knowledge, this is the first report of using Bi2O3 as a catalyst support in fuel cell applications. The material was characterized by powder X-ray diffraction and various microscopic techniques. This composite showed remarkable activity as well as stability toward the electro-oxidation of ethanol in comparison to commercially available Pt/C. The order of the reactivity was found to be commercial Pt/C (50.4 mA/m2mgPt-1) < Pt/Bi2O3(10) (108 mA/m2mgPt-1) < PtAu/Bi2O3(10) (459 mA/m2mgPt-1). The enhancement in the activity can be explained through cooperative effects, namely, ligand effects of gold and Bi2O3 support, which helps in removing carbon monoxide molecules to avoid the poisoning of the Pt active sites.