Optimization, modeling and characterization of sol-gel process parameters for the synthesis of nanostructured boron doped alumina catalyst supports

• RSM is a useful tool to optimize the process variables of synthesis of B-Al2O3 by sol-gel method.
• Presence of tetraborate ion in hydrolysis cause the formation of nano-spheres.
• Increase in the number of substituted tetraborate ion leads smaller nano-spheres.
• Agglomerate size is controllable in condensation step.
• High hydrolysis ratio results uniform and narrow mesoporous structure with interpore formation.

A response surface methodology (RSM) was implemented to investigate the effect of sol-gel synthesis variables in the structural and textural properties of boron doped alumina synthesis. The effects of four independent operating variables (mol HNO3/mol AIP, concentration of AIP, mol H2O/mol AIP, and boron weight/total catalyst support weight) were explored on the responses, namely the total surface area, and the BJH desorption pore diameter of boron doped alumina (B-Al2O3) supports. The variables were optimized and the models were validated by the experimental runs which were synthesized by simultaneously adjusting the operating variables giving maximum deviation of 3.3% from the desired value. The synthesized samples were characterized by XRD, BET, SEM, ICP-OES and TEM techniques. The characterization studies pointed out the interactions between process variables significantly affect the morphology of the catalyst support. The morphology of the supports can be modified from cracked surface to nano-sphere formation by the introduction of boron.

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