A Study on the Surface Silanol Groups Developed by Hydrothermal and Acid Treatment of Faujasite Type Zeolites

Epoxidation of cyclohexene on Ti/SiO2 catalysts prepared by chemical grafting TiCl4 on deboronated silica xerogel

“…But we did not observe the increase in the band intensity of silanol groups after the deboronation, unlike the case for beta zeolite that shows more silanol groups after the deboronation [19]. The intensity of the broad band at 3700-3400 cm −1 is decreased with the increased pretreatment temperatures due to the dehydroxylation of the silanol groups [18], and some defects could be produced after the deboronation and the subsequent calcination.…”

“…For deboronated samples, the 3740 cm −1 band remains unchanged, but the broad band at 3700-3400 cm −1 shifts to lower frequencies. This is because those silanol groups are derived after the boron atoms were removed, and the silanol groups may be interacted with each other via the hydrogen bonding [18]. But we did not observe the increase in the band intensity of silanol groups after the deboronation, unlike the case for beta zeolite that shows more silanol groups after the deboronation [19].…”

Catalytic Combustion of Dioxin Analogue Compounds on Pt Supported Zeolite

“…The high Pt dispersion on H-USY(420) might be caused by mesopores with ca. 2 nm diameter formed by the deep dealumination of USY 20) . The influence of water vapor was then studied because the flue gas from incinerators always contains a large fraction of water vapor.…”

FT-IR studies of zeolite materials

“…Lattice termination silanol groups are mainly located on the external surface Hydroxyl nests can be produced in the process of steaming (heating to high temperatures in the presence of water vapor), as described by the equation shown in Figure 1.3 [18,19]. The removal of framework aluminum also occurs during steaming, forming non-framework aluminum species such as Al(OH) 3 .…”

“…In addition, gasphase absorptions have been subtracted from each of the FT-IR spectra. 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,21,23,25,27,30 min, respectively. The blank grid is used as a reference.…”