Studies on CO oxidation performance of Pt/Au–TiO₂ catalyst: role of high temperature reduction and gas discharge

Noble metal like Pt or Au deposited on reducible oxides like TiO₂ is one of the promising catalysts for CO oxidation, which has many applications including developing long-life sealed-off CO₂ lasers, pollution control, etc. Catalytic oxidation of CO is pre-requisite for sealed-off CO₂ lasers, because dissociation of lasing CO₂ molecules in gas discharge decreases the laser power and may kill laser action in few minutes. Hence, this study was aimed to investigate the CO oxidation efficiency of in-house prepared Pt–TiO₂ and Au–TiO₂ catalysts, both at room temperature and under discharge conditions. The results of XPS and CO₂ conversion measurements revealed that the post-reduction of catalyst plays a very important role for increasing the Pt⁰ and efficiency of CO oxidation to about 80%. Importantly, in the presence of gas discharge, considerably higher catalytic performance was observed for Pt–TiO₂ catalyst with respect to their performance at room temperature and commercial gold (Au)-coated catalyst present in CO₂ laser tubes.