Modification of SBA-15 for stabilizing supported oxides

Abstract

AbstractThe effect of treating SBA-15 with a piranha solution at room temperature was studied for purposes of stabilizing a WO3 film deposited by Atomic Layer Deposition (ALD). For unmodified SBA-15, the film was found to migrate out of the SBA-15 pore structure between 573 and 773 K; however, WO3 remained within the pores in piranha-treated samples at 773 K, as demonstrated by X-Ray Diffraction and Transmission Electron Microscopy. Although N2 adsorption isotherms showed that the pore structure of SBA-15 was unaffected by the piranha treatment, the silanol content increased, as shown by water adsorption isotherms and Diffuse Reflectance Infrared Spectra of the silanol region. Temperature-programmed desorption results for 2-propanol also suggested that the silanols were more reactive in the piranha-treated samples. The results demonstrate the importance of surface modification of SBA-15 for the preparation of supported-oxide catalysts.