Catalytic activity of cobalt grafted on ordered mesoporous silica materials in N2O decomposition and CO oxidation

Binary CoOx–SiO2 Porous Nanostructures for Catalytic CO Oxidation

“…For instance, Lima et al prepared two Co/SiO 2 catalysts (with 10 wt %) by sol−gel one pot (Op) and impregnation (Im) methods and obtained T 50 values around 425 °C (Op sample) and 270 °C (Im sample) under operating conditions similar to the ones used here. 48 With a 12 wt %Co/SBA-15 catalyst generated by infiltration of cobalt acetate on sol−gel-based SBA-15 material, Kubonǒváet al 49 observed a T 50 temperature of 164 °C under experimental conditions more propitious because they used a feed containing 0.1 mol %CO with WHSV = 60 000 L•h −1 •kg −1 compared in this study to 11.6 mol %CO with WHSV = 120 000 L•h −1 •kg −1 . Several authors have reported that generally Co-silica materials give poor performances in CO oxidation, in contrast to Co-alumina or Co-titania, because of the weak interactions existing between silica and cobalt oxide leading to the sintering of Co species during the thermal treatment.…”

Adsorption of Rhodamine 6G Dye onto Al-MCM-41 and MCM-41 Mesoporous Materials

“…The observed three well-resolved diffraction peaks (100), (110), and (200) confirmed the highly ordered and hexagonal mesoporous structure (space group P6mm) of MCM-41 type. 23,35 However, for Al-MCM-41, the reflection of (100) plane appeared at 2θ = 2.30°, and the presence of two small peaks at 2θ = 3.59° (110) and 2θ = 4.26° (200). The presence of three diffraction peaks confirmed the regular structure of the Al-containing MCM-41 sample with hexagonal symmetry.…”

“…The broad and most intense band around to 484 cm −1 is attributed to the asymmetric stretching vibrations of the Si−O−Si bond. 35,41 Otherwise, the less intense band at 800 cm −1 is associated with symmetric Si−O−Si stretching. However, Raman band at 973 cm −1 is associated with Si−OH stretching mode of vi-brations of the surface silanol group.…”

Theoretical prediction of superatom WSi12-based catalysts for CO oxidation by N2O

“…In the past several decades, a number of catalysts have been proposed for this chemical conversion of N 2 O and CO to N 2 and CO 2 . 9–17 Among the reported catalysts, atomic clusters with different structures and compositions, 16 such as Cu n − , 14 Ag 7 Au 6 , 15 M@Cu 12 (M = Cu, Pt, Ru, Pd, and Rh), 17 and Au 20 , 18 have played an important role in understanding the catalytic mechanism and providing novel alternative catalysts for this CO oxidation reaction. However, it must be admitted that such cluster catalysts are difficult to prepare for further practical applications in view of their high active surface leading to aggregation.…”