Design of mesoporous alumina–ceria films on glass: Compositional tuning leads to mesoscopic transformations

• Synthesis of mesoporous alumina–ceria films with different Al/Ce compositions.
• Mesophase transformation from Im  3¯m to Ia3d is related to salting-in and out mechanisms.
• High ceria loading leads to formation of phase-segregated ceria nanoparticles.

We report the first synthesis of 3D ordered cubic mesoporous alumina–ceria films on glass using the triblock copolymer F127 as a structure directing agent. Aluminium tri-sec-butoxide partially chelated with acetyl acetone and cerium nitrate were used as alumina and ceria precursors, respectively, and the concentration of ceria in alumina was varied from 0 (pure Al) to 100 (pure Ce) mol%. Symmetry of mesopores and structural morphologies were tuned simply by alumina/ceria compositional control. The mesophase transformation from cubic Im  3¯m to Ia3d symmetries occurred when the concentration of cerium nitrate was increased from 0–1 mol% to 5–8 mol%; while higher ceria loadings resulted in the formation of phase segregated alumina-rich spheres embedded in a ceria-rich matrix. The mechanism of the evolution of mesoscopic transformations were established by transmission SAXS studies of the alumina–ceria sols and GIXRD, FESEM, TEM, FTIR and Raman analysis of the films. The crystalline nature of alumina–ceria films with respect to different ceria loadings heat-treated at 400 and 800 °C were also reported.

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