Simple solid mixed Pt/TiO2-ZrO2 catalyst for CO oxidation with excellent sulfur and water resistance at relatively low temperature

To achieve efficient and stable removal of carbon monoxide (CO) in complex flue gases, a series of Pt/1TiO2-xZrO2 catalysts were prepared using a simple solid mixing method, and their catalytic performances for CO oxidation were studied in simulated flue gases containing H2O and SO2. The synthesized Pt/1TiO2-3ZrO2 exhibited optimal sulfur and water resistance. SO2-TPD testing indicated that the minimum amount of sulfate species deposited on Pt/ZrO2-SC and the introduction of TiO2 promoted the desorption of SO2 from ZrO2-SC. The infrared spectrum indicated that the preferential adsorption of SO2 onto the multiphase ZrO2 surface prevented the occupation of the active species by SO2. The enhanced acidity of the carrier after binding to SO42− inhibited the further adsorption of SO2 on the catalyst surface. X-ray photoelectron spectroscopy showed that Pt nanoparticles with low dispersibility maintain a stable metallic state during the reaction process while retaining their CO oxidation capabilities by suppressing the generation of the Pt-O-SO3 groups. When water was simultaneously present in the flue gases, hydrophilic TiO2 promoted the dissociation of H2O on the catalyst surface, and formed the surface hydroxyl groups with stronger SO2 reactivity, which further inhibited the occupation of the active site Pt0 by SO2.