Hollow @CuMgAl double layered hydrotalcites and mixed oxides with tunable textural and structural properties, and thus enhanced NH3-NOx-SCR activity

Well-organized, spherical, mesoporous hollow @CuMgAl-LDHs (layered double hydroxides) are prepared by the controlled removal of the SiO₂ from SiO₂@CuMgAl-LDH core-shell hybrids that in turn are synthesized via a bottom-up strategy. The materials are prepared with various Cu/Mg molar ratios (Cu/Mg = 0.05-0.50) while keeping the ratio of Cu and Mg constant, (Cu + Mg)/Al = 2. The effect of Cu doping and the silica core removal process (conducted for 4 h at 30 °C using 1 M NaOH) on the chemical composition, morphology, structure, texture and reducibility of the resulting materials are described. @CuMgAl-MOs (mixed oxides) obtained by thermal treatment of the @CuMgAl-LDHs are active and selective catalysts for the selective catalytic reduction of NO_x using ammonia, and effectively operate at low temperatures. The N₂ yield increases with increased Cu content in the CuMgAl shell, which is associated with the easier reducibility of the Cu species incorporated into the MgAl matrix. @CuMgAl-MOs show better catalytic performance than bulk CuMgAl MOs.

Nanoarchitectured two-dimensional layered double hydroxides-based nanocomposites for biomedical applications

Despite the exceptional physicochemical and morphological characteristics, the pristine layered double hydroxides (LDHs), or two-dimensional (2D) hydrotalcite clays, often suffer from various shortcomings in biomedicine, such as deprived thermal and chemical stabilities, acid-prone degradation, as well as lack of targeting ability, hampering their scale-up and subsequent clinical translation. Accordingly, diverse nanocomposites of LDHs have been fabricated by surface coating of organic species, impregnation of inorganic species, and generation of core-shell architectures, resulting in the complex state-of-the-art architectures. In this article, we initially emphasize various bothering limitations and the chemistry of these pristine LDHs, followed by discussions on the engineering strategies of different LDHs-based nanocomposites. Further, we give a detailed note on diverse LDH nanocomposites and their performance efficacy in various biomedical applications, such as drug delivery, bioimaging, biosensing, tissue engineering and cell patterning, deoxyribonucleic acid (DNA) extraction, as well as photoluminescence, highlighting the influence of various properties of installed supramolecular assemblies on their performance efficacy. In summary, we conclude with interesting perspectives concerning the lessons learned to date and the strategies to be followed to further advance their scale-up processing and applicability in medicine.