A simple co-impregnation route to load highly dispersed Fe(III) centers into the pore structure of SBA-15 and the extraordinarily high catalytic performance

Highly dispersed iron centers supported on SBA-15 were successfully prepared via a simple incipient wetness co-impregnation route by casting furfuryl alcohol (FA) solution of iron (III) acetylacetonate (Fe(acac)₃), which were used as carbon and iron sources, respectively, into the pore structure of SBA-15, followed by the subsequent removal of carbonized FA. Various techniques such as XRD, TEM, N₂ sorption, UV-vis, XPS and EPR, were employed to characterize the prepared catalysts. It was shown that both Fe₂O₃ nanoclusters and isolated iron species were present and highly dispersed onto the pore surface of SBA-15, due to the presence of abundant carbon source co-impregnated, with well-maintained, highly ordered and open mesoporous structure. A great number of acidities was introduced by the loading of Fe₂O₃, and the catalytic performance was tested on the Friedel-Crafts benzylation of benzene by benzyl chloride. Under the optimized reaction condition, the catalyst showed a superior catalytic performance with a 100% yield of monoalkylated product within 1.5 min at 60 °C. The catalyst demonstrated high reusability and stability, the yield of diphenylmethane was still higher than 90% after 6 runs. Moreover, the catalyst was still active at the temperature as low as 40 °C. Such a strategy is verified applicable to prepare other well-dispersed metal oxides, i.e. Mn_xO_y loaded into the pore structure of mesoporous materials.