Platinum Mesoporous Silica Catalysts for Liquid Media Oxidation

Abstract

ABSTRACTMono- and bimetallic heterogeneous catalysts with mesoporous structure were prepared in two steps. In the first step, SBA-15 and amino-SBA-15 supports were prepared, and in the second, these materials were impregnated with Pt and Co precursors. High-surface-area supports like SBA-15 afford highly dispersed metal oxide species which are the key parameter in the rather difficult oxidation of alkenes with hydrogen peroxide. The obtained mesoporous catalysts with 0.1% Pt and 1% Co were characterized by nitrogen adsorption, ultraviolet–visible, Fourier-transform infrared, and X-ray absorption spectroscopies. X-ray absorption spectroscopy demonstrated the presence of Pt–oxygen for both Pt–SBA-15 and Pt–amino-SBA-15 samples, suggesting a higher number of oxidized platinum species in the second material. The adopted procedure was simple, green, and efficient for 3-butene-1-ol, cis-2-butene-1, 4-diol, and cyclohexene oxidation. The use of H2O2, a clean oxidant, is an important feature of a green chemical reaction since it produces only water as the by-product. The mesoporous structure of the silica-supported catalysts enables better accessibility of active sites to bulky substrate molecules, reflected in the high conversions and enhanced selectivity.