Study On The Complete Oxidation Of Formaldehyde Over MnO_x-CeO₂ Solid Solution Catalysts

Formaldehyde is regarded as the major indoor pollutant emitted from the widely used building and decorative materials in airtight buildings. It is evidenced that long-term exposure to indoor air even containing a few ppm of formaldehyde may cause adverse effects on human health. Thus, great efforts have been made to reduce the indoor emission of formaldehyde for satisfying the stringent environmental regulations. Catalytic complete oxidation using heterogeneous catalysts is a powerful technique for the purification of indoor air.The catalytic activity of MnO_x-CeO₂ solid solution for the complete oxidation of formaldehyde strongly depended on the preparation route and the calcination temperature. It revealed that MnO_x-CeO₂ mixed oxides prepared by modified coprecipitation method and calcined at 773 K exhibited extraordinarily high catalytic activity, and 100% formaldehyde conversion could be achieved at a temperature as low as 373 K, which was superior to those by sol-gel method, coprecipitation method at the some reaction conditions. Structure analysis by H₂-TPR and XPS revealed that there were more Mn4+ species and richer lattice oxygen on the surface of the MnO_x-CeO₂ catalyst prepared by the modified coprecipitation method than those by sol-gel method or coprecipitation method, which were responsible for its higher catalytic activity.The performance of MnO_x-CeO₂ supported noble metals (Pt, Ag or Au)...