Abstract
Ordered mesoporous Zr-Al composite oxide materials (denoted as OMZA-x) with different Zr contents have been synthesized by a solvent evaporation-inducing self-assembly procedure associated with a thermal treatment at 100 °C. A cooperative co-assembly process of amphiphilic triblock copolymer F127 molecules and inorganic hydroxyl species originated from the hydrolysis of Zr and Al precursors was proposed to explain the synthesis of OMZA-x. Compared to ordered mesoporous alumina prepared without introducing Zr species, the resultant OMZA-x exhibited a much more ordered mesostructure combined with a distinct increase in the pore volume and specific surface area. The highly homogenous doping of Zr into the mesopore walls together with the formation of Zr-O-Al bonds can effectively enhance the thermal and hydrothermal stability of OMZA-x. For instance, the ordered mesostructure and excellent textural properties of OMZA-6 prepared with the optimum atomic ratio of Al to Zr of 6 could be well maintained even after a high-temperature treatment at 1000 °C for 1 h or a hydrothermal treatment at 100 °C for 6 h.
Highlights
For samples OMZA-x and ordered mesoporous mesoporous alumina alumina (OMA), the evidence for the presence of ordered mesostructure is presented by the small-angle X-ray diffraction diffraction (XRD) patterns
Almost all Zr hydroxyl species originated from the hydrolysis of Zr synthesis introduced pathway
Zr and Al increased at the atomic level and the formation of Zr-O-Al bondspore can volume be responsible for OMZA-x obviously mesostructural order, significantly increased and specific surface possessing an obviously increased mesostructural order, significantly increased pore volume and area, and remarkably enhanced thermal and hydrothermal stability
Summary
Since the first invention of M41s series of silica materials [1,2], ordered mesoporous materials possessing large pore volume and high specific surface area as well as tunable mesoporous structures have attracted extensive attention for the development of high-efficiency catalysts using in the conversion of macromolecules [3], and numerous non-silicon-based ordered mesoporous materials with excellent structural, textural, and surface properties have been successively synthesized [4,5,6,7]. The evaporation induced self-assembly (EISA) method is another soft-template self-assembly approach for the successful preparation of ordered mesoporous materials, especially ordered mesoporous metal oxides [7,8,21,22,23]. Via such a method, a series of ordered mesoporous alumina materials with different mesostructures and tunable mesoporous sizes have been successfully prepared by adjusting the hydrophilic-hydrophobic properties of surfactants or introducing suitable catalysts into the initial synthesis solution [8,24,25,26]. The effects of the doping amount of zirconium on the synthesis of OMZA-x materials and their performance boost were investigated, and the possible synthesis mechanism was provided
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