Gold-supported tin dioxide nanocatalysts for low temperature CO oxidation: preparation, characterization and DRIFTS study

Abstract

A series of gold-supported tin dioxide (Au/SnO2) nanocatalysts were prepared by a deposition–precipitation method using SnO2 powders prepared by the sol–gel dialytic processes as supports, and were characterized by means of XRD and XPS techniques. The catalytic properties of the prepared Au/SnO2 nanocatalysts were evaluated by low-temperature carbon monoxide oxidation using a microreactor-GC system. The results showed that the catalytic behavior of the Au/SnO2 system was remarkably influenced by the deposition pH, the reaction solution concentration and the thermal pretreatment temperature of the catalyst. The DRIFTS study results indicated that CO adsorbed on the Au/SnO2 catalyst reacted with support surface lattice oxygens and hydroxyl groups to form oxidation products, i.e., CO2–, HCOO–, CO32–, HCO3– and CO2, and the gas phase oxygen acted as an activator for the reaction of CO with support surface lattice oxygens and hydroxyl groups.