Delamination‐Driven Formation of Stronger Basic Sites in Mg/Al Mixed Metal Oxides

Increasing the density of accessible active sites is a general strategy in the development of solid catalysts. Delamination of layered double hydroxides (LDHs) offers an attractive route to obtain mixed metal oxides (MMOs) with enhanced morphological and basic properties via thermal decomposition. However, the role of post‐delamination treatments, particularly the drying step, has received little attention. Here, we investigate the combined effects of aqueous‐phase delamination and subsequent drying methods on the textural and surface characteristics of MMOs. Delamination introduces structural disorder and yields thinner, crumpled layers, as confirmed by cryogenic transmission electron microscopy and powder X‐ray diffraction. Freeze‐drying (FD) is essential for preserving the disordered structure, whereas oven‐drying leads to reassembly into ordered layers due to atmospheric CO ₂ exposure. CO ₂ chemisorption measurements show a 4.3‐fold increase at 400°C for an MMO synthesized via sonication‐assisted delamination followed by FD, relative to its nondelaminated counterpart. Temperature‐programmed desorption combined with in situ fourier transform infrared spectroscopy confirms the generation of stronger surface basic sites that effectively retain CO ₂ at elevated temperatures. These findings demonstrate that the stacking state of nanosheet aggregates during the LDH‐to‐MMO transformation governs not only textural properties but also the distribution and strength of surface basic sites, extending beyond textural improvements.