Magnetic metal-organic framework (MOF) composites show highly efficient CO2 desorption capacities upon their exposure to an alternating magnetic field, demonstrating a magnetic induction swing strategy for potentially low-energy regeneration of MOF adsorbents.

Metal−organic frameworks (MOFs) are promising nanomaterials with unprecedented capacity to store small molecules. Despite this huge capacity, proposed methods for releasing these molecules are not yet feasible at a meaningful scale, largely because of the strong binding of the molecules and the thermally insulating nature of the adsorbent. It is likely that large amounts of energy would be required for operation at scale. Furthermore, the high adsorption capacity of MOFs is not typically matched by a high working capacity; adsorbed molecules are not readily retrieved. Here we show a series of magnetic framework composites (MFCs) synthesized from ferri-magnetic MgFe 2 O 4 nanoparticles and the Zr-based MOF UiO-66 can be deployed in a magnetic induction swing adsorption process for CO 2 capture and release. Exposure of the MFCs to an alternating current magnetic field resulted in the generation of heat by the embedded magnetic nanoparticle and fast release of CO 2 from the MOF, with an unprecedented 100% of adsorbed CO 2 released under a 42 mT field. This was achieved at a regeneration time of 240 s. The efficiency of the MISA process was shown to be dependent on the amount of MFC used, with efficiencies reaching 60% at just a gram scale. These local "nanoheaters" overcome the thermally insulating nature of the adsorbent, which has promising implications for use at scale. Additionally, the ability to access 100% of the adsorption capacity permits the use of strongly adsorbing, high-capacity MOFs that were previously discarded.

Porosity and surface area analysis play a prominent role in modern materials science. At the heart of this sits the Brunauer–Emmett–Teller (BET) theory, which has been a remarkably successful contribution to the field of materials science. The BET method was developed in the 1930s for open surfaces but is now the most widely used metric for the estimation of surface areas of micro‐ and mesoporous materials. Despite its widespread use, the calculation of BET surface areas causes a spread in reported areas, resulting in reproducibility problems in both academia and industry. To prove this, for this analysis, 18 already‐measured raw adsorption isotherms were provided to sixty‐one labs, who were asked to calculate the corresponding BET areas. This round‐robin exercise resulted in a wide range of values. Here, the reproducibility of BET area determination from identical isotherms is demonstrated to be a largely ignored issue, raising critical concerns over the reliability of reported BET areas. To solve this major issue, a new computational approach to accurately and systematically determine the BET area of nanoporous materials is developed. The software, called “BET surface identification” (BETSI), expands on the well‐known Rouquerol criteria and makes an unambiguous BET area assignment possible.

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A dual stimuli-responsive metal–organic framework exhibits a cooperatively enhanced gas desorption capacity upon simultaneously exposing it to both UV light and an alternating magnetic field, highlighting a low-energy yet highly efficient strategy to regenerate MOF adsorbents.

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Oxygen is a critical gas for medical and industrial settings. Much of today's global oxygen supply is via inefficient technologies such as cryogenic distillation, membranes or zeolites. Metal–organic frameworks (MOFs) promise a superior alternative for oxygen separation, as their fundamental chemistry can in principle be tailored for reversible and selective oxygen capture. We evaluate the characteristics for reversible and selective uptake of oxygen by MOFs, focussing on redox‐active sites. Key characteristics for separation can also be seen in MOFs for oxygen storage roles. Engineering solutions to release adsorbed oxygen from the MOFs are discussed including Temperature Swing Adsorption (TSA), Pressure Swing Adsorption (PSA) and the highly efficient Magnetic Induction Swing Adsorption (MISA). We conclude with the applications and outlooks for oxygen capture, storage and release, and the likely impacts the next generation of MOFs will have on industry and the broader community.

Which is the simplest logical structure for which there is quantum nonlocality? We show that there are only three bipartite Bell inequalities with quantum violation associated with the simplest graph of relationships of exclusivity with a quantum-classical gap. These are the most elementary logical Bell inequalities. We show that the quantum violation of some well-known Bell inequalities is related to them. We test the three Bell inequalities with pairs of polarization-entangled photons and report violations in good agreement with the quantum predictions. Unlike other experiments testing noncontextuality inequalities with pentagonal exclusivity, the ones reported here are free of the compatibility loophole.Comment: REVTeX4, 6 pages, 4 figure