Effect of kaolin on aluminum loading success in synthesis of Al-SBA-15 catalysts: Activity test in ethanol dehydration reaction

Abstract

Aluminum incorporated SBA-15 catalysts were prepared via hydrothermal method using together with aluminum salt and kaolin as aluminum source. Aluminum loading to the SBA-15 structure did not destroy the characteristic peaks of SBA-15 (from X-Ray diffraction (XRD) patterns) and it was led to increase of surface area values. Energy dispersive spectroscopy (EDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES) results demonstrated that increase of kaolin amount positively affected the success of aluminum loading. UV-visible diffuse reflectance (UV-Vis DR) and X-ray photoelectron spectroscopy (XPS) spectra showed that aluminum species were settled in the form of metal oxide. Fourier transform infrared (FTIR) spectra exhibited the characteristic structural bands of SBA-15. Generally the peak intensities of the acid sites increased slightly with the aluminum incorporation and this increase showed mostly at Lewis acid sites. The highest ethanol conversion and ethylene selectivity was observed as 0.95 and 1.00 at 400 degrees C, respectively.