Al-MCM-41 inside a glass–ceramic scaffold: A meso–macroporous system for acid catalysis

Al-MCM-41 was incorporated, through a sol–gel based dipping approach, inside a glass–ceramic scaffold belonging to the SiO2–CaO–Na2O–Al2O3 (SCNA) system, to obtain an acidic system with bimodal porosity in the meso- and macro-range. First, SCNA was investigated by means of wide-angle X-ray diffraction (XRD), differential thermal analysis (DTA) and hot stage microscopy (HSM) in order to select the optimal sintering condition to fabricate the macroporous foam-like carrier for Al-MCM-41. Then, Al-MCM-41 was incorporated into the SCNA scaffold; the pH value of Al-MCM-41 synthesis solution, used for the scaffold impregnation process, was shown to be a crucial parameter, on identical scaffold dipping time, to determine the distribution and the stability of the incorporated phase. The systems were characterized by means of XRD, N2 adsorption/desorption, TGA and SEM coupled with EDS.The Al-MCM-41-containing scaffold is active in the acid-catalyzed sucrose hydrolysis, chosen as model reaction, at variance with the scaffold as such.