ChemInform Abstract: Mesoporous Titanosilicate Molecular Sieves Prepared at Ambient Temperature by Electrostatic (S+I‐, S+X‐I+) and Neutral (S°I. degree.) Assembly Pathways: A Comparison of Physical Properties and Catalytic Activity for Peroxide Oxidations.

Abstract

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Room Temperature Synthesis of Ti–MCM-48 and Ti–MCM-41 Mesoporous Materials and Their Performance on Photocatalytic Splitting of Water

“…28,48À50 An increase in the width of the absorption peaks indicates octahedral geometry of the Ti species deposited by the postimpregnation method. 51,52 It is noticed that, with an increase of the Ti loading, there is a red shift of the absorption band of the TiÀMCM-48 samples. This is due to the formation of small sized TiO 2 clusters when the titania content keeps increasing.…”

“…It shows that, for the former ones, the band gap energy is in the range from 3.5 to 3.8 eV while for the latter ones it varies between 3.3 and 3.6 eV. In Figure (A), all the postimpregnated Ti–MCM-48 samples exhibit broad absorption in the range 200–350 nm with a strong absorption peak in the 210–220 nm range, which is due to the ligand to metal charge transfer (LMCT) from O 2– to Ti 4+ . ,− An increase in the width of the absorption peaks indicates octahedral geometry of the Ti species deposited by the postimpregnation method. , It is noticed that, with an increase of the Ti loading, there is a red shift of the absorption band of the Ti–MCM-48 samples. This is due to the formation of small sized TiO 2 clusters when the titania content keeps increasing.…”

Study of Adsorptive Denitrogenation of Diesel Fuel over Mesoporous Molecular Sieves Based on Breakthrough Curves

“…There is no absorption for HMS and MCM-41 without the introduction of framework Ti. Ti-HMS presents an absorption band near 210–225 nm, which originates from the charge transfer of oxygen 2p electron to the empty 3d orbit of Ti 4+ , indicating the existence of framework Ti in tetrahedral coordination . The absorption band at 260–280 nm is attributable to the partially polymerized hexacoordinated Ti species in the materials .…”

Size-Dependent Catalytic Activity of Oxo-Hydroxo Titanium Sub-Nanoislets Grafted on Organically Modified Mesoporous Silica

“…In addition, these routes inevitably lead to a mixture of Ti species of various coordination numbers, various nuclearities, locations, and exposure to the gas phase. 14,18 Though more complicated to implement, the postgrafting routes provide a better control over these parameters. In these cases, titanium chloride and other overly reactive precursors (including some titanium alkoxides) are disadvantageous, as they also favor Ti(IV) ion clustering at the channel entrance of the mesoporous silica support.…”