A Fine-Tuned Fluorinated MOF Addresses the Needs for Trace CO₂ Removal and Air Capture Using Physisorption

The development of functional solid-state materials for carbon capture at low carbon dioxide (CO₂) concentrations, namely, from confined spaces (<0.5%) and in particular from air (400 ppm), is of prime importance with respect to energy and environment sustainability. Herein, we report the deliberate construction of a hydrolytically stable fluorinated metal–organic framework (MOF), <b>NbOFFIVE</b>-1-Ni, with the appropriate pore system (size, shape, and functionality), ideal for the effective and energy-efficient removal of trace carbon dioxide. Markedly, the CO₂-selective <b>NbOFFIVE</b>-1-Ni exhibits the highest CO₂ gravimetric and volumetric uptake (ca. 1.3 mmol/g and 51.4 cm³ (STP) cm^–3) for a physical adsorbent at 400 ppm of CO₂ and 298 K. Practically, <b>NbOFFIVE</b>-1-Ni offers the complete CO₂ desorption at 328 K under vacuum with an associated moderate energy input of 54 kJ/mol, typical for the full CO₂ desorption in conventional physical adsorbents but considerably lower than chemical sorbents. Noticeably, the contracted square-like channels, affording the close proximity of the fluorine centers, permitted the enhancement of the CO₂–framework interactions and subsequently the attainment of an unprecedented CO₂ selectivity at very low CO₂ concentrations. The precise localization of the adsorbed CO₂ at the vicinity of the periodically aligned fluorine centers, promoting the selective adsorption of CO₂, is evidenced by the single-crystal X-ray diffraction study on <b>NbOFFIVE</b>-1-Ni hosting CO₂ molecules. Cyclic CO₂/N₂ mixed-gas column breakthrough experiments under dry and humid conditions corroborate the excellent CO₂ selectivity under practical carbon capture conditions. Pertinently, the notable hydrolytic stability positions <b>NbOFFIVE</b>-1-Ni as the new benchmark adsorbent for direct air capture and CO₂ removal from confined spaces

Ratiometric Nanothermometer Based on an Emissive Ln³⁺-Organic Framework

Luminescent thermometers working at the nanoscale with high spatial resolution, where the conventional methods are ineffective, have emerged over the last couple of years as a very active field of research. Lanthanide-based materials are among the most versatile thermal probes used in luminescent nanothermometers. Here, nanorods of metal organic framework Tb_0.99Eu_0.01(BDC)_1.5(H₂O)₂ (BDC = 1-4-benzendicarboxylate) have been prepared by the reverse microemulsion technique and characterized and their photoluminescence properties studied from room temperature to 318 K. Aqueous suspensions of these nanoparticles display an excellent performance as ratiometric luminescent nanothermometers in the physiological temperature (300–320 K) range

Understanding Photocatalytic Activity Dependence on Node Topology in Ti-Based Metal–Organic Frameworks

Despite the drive to develop more efficient Ti-based metal–organic framework (MOF) photocatalysts, MIL-125-NH2 is still the benchmark, and only a few design principles have been offered to improve photocatalytic performance. Linker functionalization in Ti MOFs has been shown to enable photocatalysis under visible light by closing the electronic band gap, significantly improving charge carrier lifetimes. Limited by known Ti-based MOFs, the role of node nuclearity and topology on photocatalytic activity remains unclear. Here, we report a new MOF, ICGM-1, a 3D-connected framework featuring 1D Ti–O rods. Photocatalytic hydrogen evolution reveals a significant difference in activity, which we attribute solely to node geometry. Using time-resolved spectroscopy and DFT calculations, we ascribe these differences to subtle electronic and geometric properties, paving the way for the development of Ti-MOF photocatalysts

Understanding Photocatalytic Activity Dependence on Node Topology in Ti-Based Metal–Organic Frameworks

Despite the drive to develop more efficient Ti-based metal–organic framework (MOF) photocatalysts, MIL-125-NH2 is still the benchmark, and only a few design principles have been offered to improve photocatalytic performance. Linker functionalization in Ti MOFs has been shown to enable photocatalysis under visible light by closing the electronic band gap, significantly improving charge carrier lifetimes. Limited by known Ti-based MOFs, the role of node nuclearity and topology on photocatalytic activity remains unclear. Here, we report a new MOF, ICGM-1, a 3D-connected framework featuring 1D Ti–O rods. Photocatalytic hydrogen evolution reveals a significant difference in activity, which we attribute solely to node geometry. Using time-resolved spectroscopy and DFT calculations, we ascribe these differences to subtle electronic and geometric properties, paving the way for the development of Ti-MOF photocatalysts