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In this work, we present the preparation of hybrid materials constituted by a Metal Organic Framework (type CPO-27-Mg) and a mesoporous silica (type KIT-6) which were successfully assembled through an in situ hydrothermal method. The composites were characterised by powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), microscopic techniques (SEM and TEM), N2 adsorption–desorption isotherms at 77 K and CO2 adsorption at 273 K; these techniques confirmed the obtaining of hybrid materials and not simple physical mixtures. Finally, the hybrid materials were tested in the CO2 adsorption at different temperatures and from 0–10 bar of pressure, where the exposure to high relative humidity were also monitored. The CPO-27-Mg@KIT-6 (1 : 1) and (2 : 1) composites exhibited interesting values of CO2 adsorption capacity, compared with those reported in the literature. Therefore, this study opens new pathways for designing porous structured MOF-based materials with advanced gas separation performance. [ABSTRACT FROM AUTHOR]

This research focuses on developing MIL-53-type compounds with Fe obtained with ligands derived from PET waste, followed by the controlled addition of hydrofluoric acid (HF). Incorporating HF into the MOF structure induced substantial changes in the material textural properties, resulting in a significant change in CO 2 adsorption. Furthermore, a distinctive structural alteration (breathing effect) was observed in the CO 2 isotherms at different temperatures; these structural changes have not been observed by X-ray diffraction (XRD) because this characterization has been performed at room temperature, whereas the adsorption experiments were conducted at 260, 273, and 303 K and different pressures. Subsequently, DFT studies were performed to investigate the CO 2 -filling mechanisms and elucidate the material respiration effect. This approach offers promising opportunities for sustainable materials with improved gas adsorption properties., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

In this work, the influence of degassing temperature and urea functionalization were investigated as ways to improve the CO 2 adsorption performance of CPO-27-Mg. Through post-synthesis modification treatments, four samples with different degrees of urea functionalization were obtained, incorporating 10, 25, 50, and 100% of urea concerning the metal sites of the MOF. Alternatively, the influence of the degassing temperature of the non-functionalized MOF between 70 and 340 °C was also evaluated. The resulting compounds were characterized by N 2 adsorption-desorption isotherms at -196 °C using TGA-MS, FTIR, and PXRD. Finally, the thermally treated and functionalized CPO-27-Mg was evaluated for CO 2 capture.

Crystal structure and properties of Sr 11 Mo 4 O 23 treated at 1100 and 1400 °C were studied via synchrotron X-ray powder diffraction and thermogravimetric analysis, coupled with mass spectrometry. Synchrotron studies reveal the crystallographic effect of the annealing temperature, showing that the lowest-temperature phase must be defined in a triclinic symmetry, in contrast to the cubic one obtained at 1400 °C. The mass spectrometry allowed the identification of the released compounds during the thermogravimetric analysis, thus unveiling the physicochemical behavior of the sample during the heating process. Furthermore, an aging analysis was made, confirming the superior stability of this sample when it is treated at 1400 °C. Finally, an optimized sintering procedure allowed us to obtain a superior density and hence the highest conductivity measured so far for this system., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)