Study On The Catalytic Oxidation Performance Of SnO₂Catalysts:Surface And Bulk Modification By Praseodymium

SnO2is an n-type semiconductor,it is rich in surface deficient oxygen. Through surface and bulk modification by other metals, SnO2has more catalytic oxidation activity and thermal stability..In this paper,Praseodymia doped SnO2catalysts were prepared with precipitation-deposition, coprecipitation solgel, impregnation method The samples were characterized by means of Inductive Coupled Plasma Emission Spectrometery (ICP), N2adsortion-desorption with Brunauer-Emmett-Teller Technique (N2-BET), X-ray Podwer Diffraction (XRD), H2Temperature Programmed Reduction (H2-TPR), Thermal Gravity Analysis-Differential Scanning Carorimetry (TGA-DSC) and X-ray Photoelectron Spectroscopy Analysis (XPS) and used for CH4and CO oxidation. Through the studies of the surface and bulk modification by praseodymium, the corresponding optimized conditions is obtained.Praseodymia-doped SnO2catalysts preprared by precipitation-deposition method have better catalytic activity. Pr was found to disperse finely onto the surface of SnO2, and had some strong interaction with it, thus stabilizing the surface area of the resulted catalysts as well as producing larger amount of active oxygen species. It is also found that the activity of catalysts compared by precipitation-deposition method was enhanced while increasing praseodymia addition amount.Catalysts prepared by co-precipitation method can’t enhance the catalytic activity for CO and CH4oxidation. It is becased that praseodymia has embeded in the crystal lattice and reacts with SnO2to form Pr2Sn2O7, it has low CO oxidation activity.Catalysts prepared by sol-gel method has lower activity than pure SnO2for the mechanical mix of the SnO2and PrO18.