来源:ACS Publications
The development of a catalyst exhibiting high resistance to SO2 and H2O, while demonstrating superior CO oxidation performance, is of significant importance for specific industrial applications. In this study, Cu and/or Pr doped OMS-2 catalysts were synthesized via a solvent-free method. Their CO oxidation efficiency, along with their resistance to H2O and SO2, was systematically evaluated under simulated flue gas conditions. The catalytic activity of the Pr10%/Cu5%-OMS-2 catalyst is much superior to that of other catalysts, where it achieved 71.8% CO conversion at 60 °C. For the long-term test, the Pr10%/Cu5%-OMS-2 catalyst showed good ability and the conversion of CO only drops to 82.7% in the presence of 5 vol % H2O and 30 ppm of SO2 for 24 h, indicating the excellent stability. At last, water and sulfur resistance mechanisms are presented and discussed, which will provide an insight in the design of water- and sulfur-resistant catalysts. Physicochemical characterization results indicate that this catalyst possesses an increased number of surface oxygen vacancies, enhanced oxygen mobility, superior low-temperature reducibility. Moreover, the presence of Pr species on the catalyst surface plays a crucial role in facilitating the redox transformation between Cu2+ and Cu+, thereby significantly augmenting the overall redox performance of the catalyst. The Pr10%/Cu5%-OMS-2 catalyst demonstrates the most excellent resistance to H2O and SO2, and the underlying reasons can be ascribed to two primary factors. First, it was also demonstrated that the presence of a small amount of surface hydroxyl groups promoted the formation of sulfite, while inhibiting the formation of strongly electron-withdrawing sulfates, thereby preserving the active Mn sites. Second, Pr2O3 exhibits preferential adsorption of SO2, thereby significantly inhibiting the formation of manganese sulfate. These two mechanisms work synergistically to enhance the catalyst’s stability and antipoisoning capability under complex operating conditions.