Synthesis of Au-Sn/TiO2 bimetallic catalysts and their application in the oxidation reaction of CO

Abstract

This work presents a study on the synthesis of bimetallic Au-Sn/TiO2 catalysts by deposition precipitation with urea method (DPU), through two procedures: sequential deposition and co-deposition. The catalysts were prepared using Na2O3Sn•3H2O and SnCl2 as tin precursor and HAuCl4•3H2O as gold precursor. For the catalysts prepared by sequential DPU, the effect of the order of deposition of the metals, and the atmosphere used during the thermal treatment after deposition of the first metal on the catalytic properties was studied. A series of four catalysts were prepared by co-deposition varying the molar ratio Au:Sn. The catalysts were evaluated in CO oxidation and characterized by different spectroscopic techniques and transmission electronic microscopy to study the influence of the synthesis methodology, the precursor and the activation conditions on their catalytic behavior.