Highly dispersed manganese oxide catalysts grafted on SBA-15: Synthesis, characterization and catalytic application in trans-stilbene epoxidation

• DOI: 10.1016/j.micromeso.2010.03.033
• Publication Date: 2010-04-02T04:35:09Z
• Authors: Qinghu Tang; Shuangquan Hu; Yuanting Chen; Zhen Guo; Yu Hu; Yuan Chen; Yanhui Yang
• Keywords: Physisorption

Abstract Manganese oxide catalysts supported on mesoporous silica SBA-15 (Mn-SBA-15) were synthesized following a controlled post-synthesis grafting process through the atomic layer deposition. N 2 -physisorption, X-ray diffraction, transmission electron microscopy, Raman spectroscopy, H 2 temperature-programmed reduction, diffuse reflectance UV–Vis, and X-ray absorption near-edge structure were employed to characterize the physicochemical properties. This grafting method can efficiently upload a large amount of Mn species, and the Mn-SBA-15 samples exhibited high surface area, large pore volume, and uniform pore size. The spectroscopic results revealed that the manganese oxides with the coexistence of Mn 2+ and Mn 3+ either highly dispersed on the mesoporous silica surface or formed small size MnO x clusters in the SBA-15 channels depending on the manganese oxide contents. These manganese catalysts with ordered pore structure exhibited superior activity and selectivity towards desired product in the liquid-phase epoxidation of trans -stilbene using tert -butyl hydroperoxide as the oxidant.