Differences in characteristics of Zr/SBA-15 and bimetallic Zr-La/SBA-15 prepared by sol–gel and hydrothermal methods

Abstract

In the present work, we report results of a comparative study of zirconium (Zr) and bimetal (Zr and La) containing in SBA-15 silica, which was prepared by conventional sol–gel and one-step hydrothermal methods. The structural and surface properties of all samples were characterized by low and high-angle XRD, nitrogen physisorption, FTIR, Raman, UV–Vis, SEM/EDX, TEM, and NH3-TPD techniques. The experimental results demonstrated that the samples obtained from the sol–gel method retain the two-dimensional hexagonal order structure of SBA-15. Compared to samples obtained from the hydrothermal method, the pore system lacking long-range order was observed. The incorporation of Zr and bimetal (Zr and La) had an effect on the textural properties of both synthesized SBA-15 samples. This modified SBA-15 mesoporous samples still exhibited high specific surface area, large pore volume and narrow pore size distribution. Surface acidity in the SBA-15 silica suggests new active sites, especially Bronsted acid type, indicating its future potential applications when acid sites are required.