Silica-titania mesoporous silicas of MCM-41 type as effective catalysts and photocatalysts for selective oxidation of diphenyl sulfide by H2O2

Abstract

Spherical Ti-MCM-41, synthetized by co-condensation method, presented very promising activity in catalytic and photocatalytic oxidation of diphenyl sulfide with H2O2 to obtain diphenyl sulfoxide and diphenyl sulfone. Mesoporous silica materials with various titanium content were analyzed with respect to chemical composition (inductively coupled plasma optical emission spectrometry), structure properties (X-ray diffraction), textural properties (low-temperature N2 adsorption-desorption), morphology (scanning electron microscopy), forms and aggregation introduced titanium species (diffuse reflectance spectroscopy, Raman spectroscopy), and surface acidity (NH3-TPD). Titanium introduced in the samples was present mainly in the form of highly dispersed species, presenting catalytic and photocatalytic activities in diphenyl sulfide oxidation with H2O2. Efficiency of the reaction increased with an increase in titanium loading in the samples and was significantly intensified under UV irradiation. The role of various Ti species in diphenyl sulfide oxidation was presented and discussed.