Unveiling the role of structure–property correlation and its validation towards engineering the application potential of sol–gel derived mesoporous gamma-alumina

Abstract

In the present study, a comprehensive investigation has been carried out on the meticulously designed surfactant-free glycerol-activated sol–gel derived mesoporous γ-alumina powder, specifically with the aim to establish the excellent prospect of the structure–property relationship towards efficiently modifying and conceptually emphasizing the correlative outlook of the application perspective. Herein, the systematic engineering of the selective synthetic parameters such as peptizing acid type and its associated solvent create great strategic influence towards methodically tuning and judiciously constructing the prime controlling facet of the overall process, which successively maintains the distinctive individuality of the sol–gel derived mesoporous gamma-alumina structure. Interestingly, the initiation of discrepancy, which was recorded at the chemical nature site of the molecular bond structure of two distinctive boehmite sols, conspicuously maintains their individuality even while experiencing the sequential advancement of the dehydroxylation process, the consequential rearrangement of the hydroxyl group, alongside the concurrent progressive diffusion of Al³⁺ ion amongst the available co-ordination sites as a function of increasing temperature. Eventually, while dictating the individual identity of the evolved gamma-alumina's structure, the study aimed at acquiring identical distinctive characteristics even at their corresponding atomic scale, bulk structure, and surface textural features in terms of revealing the Rietveld, NMR (²⁷Al and ¹H), pyridine-FTIR, TEM, and XPS spectral analysis with the exploration of comparatively higher crystallinity, greater AlO₄/AlO₆ ratio, lower Lewis and Brønsted acid sites, lesser amount of hydroxyl groups, and lower extent of agglomeration tendency in inorganic acid peptized gamma-alumina as compared to organic acid peptized gamma-alumina, which thereafter showed concrete interconnectivity by concluding with the proper demonstration of the surface area, pore morphology, and band gap study. Finally, the study presented a detailed mechanistic view with the aim to further exemplify the real-time prospect of the structure–property relationship of the two differently synthesized gamma-alumina samples in terms of categorizing the application potential, particularly in identical dye adsorption and photocatalyst fields, and consecutively building a robust scientific and technological perspective of the structure–property-performance inter-connective linkage beyond the existing limiting factor.