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Adsorption‐based cooling is an energy‐efficient renewable‐energy technology that can be driven using low‐grade industrial waste heat and/or solar heat. Here, we report the first exploration of fluorocarbon adsorption using porous covalent organic polymers (COPs) for this cooling application. High fluorocarbon R134a equilibrium capacities and unique overall linear‐shaped isotherms are revealed for the materials, namely COP‐2 and COP‐3. The key role of mesoporous defects on this unusual adsorption behavior was demonstrated by molecular simulations based on atomistic defect‐containing models built for both porous COPs. Analysis of simulated R134a adsorption isotherms for various defect‐containing atomistic models of the COPs shows a direct correlation between higher fluorocarbon adsorption capacities and increasing pore volumes induced by defects. Combined with their high porosities, excellent reversibility, fast kinetics, and large operating window, these defect‐containing porous COPs are promising for adsorption‐based cooling applications. [ABSTRACT FROM AUTHOR]

Adsorption‐based cooling is an energy‐efficient renewable‐energy technology that can be driven using low‐grade industrial waste heat and/or solar heat. Here, we report the first exploration of fluorocarbon adsorption using porous covalent organic polymers (COPs) for this cooling application. High fluorocarbon R134a equilibrium capacities and unique overall linear‐shaped isotherms are revealed for the materials, namely COP‐2 and COP‐3. The key role of mesoporous defects on this unusual adsorption behavior was demonstrated by molecular simulations based on atomistic defect‐containing models built for both porous COPs. Analysis of simulated R134a adsorption isotherms for various defect‐containing atomistic models of the COPs shows a direct correlation between higher fluorocarbon adsorption capacities and increasing pore volumes induced by defects. Combined with their high porosities, excellent reversibility, fast kinetics, and large operating window, these defect‐containing porous COPs are promising for adsorption‐based cooling applications. [ABSTRACT FROM AUTHOR]

The oxygen electrode plays a vital role in the successful commercialization of renewable energy technologies, such as fuel cells and water electrolyzers. In this study, the Prussian blue analogue-derived nitrogen-doped nanocarbon (NC) layer-trapped, cobalt-rich, core-shell nanostructured electrocatalysts (core-shell Co@NC) are reported. The electrode exhibits an improved oxygen evolution activity and stability compared to that of the commercial noble electrodes. The core-shell Co@NC-loaded nickel foam exhibits a lower overpotential of 330 mV than that of IrO2 on nickel foam at 10 mA cm-2 and has a durability of over 400 h. The commercial Pt/C cathode-assisted, core-shell Co@NC-anode water electrolyzer delivers 10 mA cm-2 at a cell voltage of 1.59 V, which is 70 mV lower than that of the IrO2-anode water electrolyzer. Over the long-term chronopotentiometry durability testing, the IrO2-anode water electrolyzer shows a cell voltage loss of 230 mV (14%) at 95 h, but the loss of the core-shell Co@NC-anode electrolyzer is only 60 mV (4%) even after 350 h cell-operation. The findings indicate that the Prussian blue analogue is a class of inorganic nanoporous materials that can be used to derive metal-rich, core-shell electrocatalysts with enriched active centers. [ABSTRACT FROM AUTHOR]

The mixed-metal strategy, by which a MOF framework with two different metal nodes was prepared, was utilized with MOF-74 for potential adsorption chiller applications. The Ni salt precursor was partially replaced during synthesis with the relatively inexpensive Zn salt. The bimetallic MOF-74 containing only a fraction of Ni was shown to provide efficient H2O adsorption performance, while utilizing the more inexpensive Zn salt thus significantly mitigated the material costs of industrial scale synthesis/applications. [ABSTRACT FROM AUTHOR]

Designing zeolites with tunable physicochemical properties can substantially impact their performance in commercial applications, such as adsorption, separations, catalysis, and drug delivery. Zeolite synthesis typically requires an organic structure-directing agent to produce crystals with specific pore topology. Attempts to remove organics from syntheses to achieve commercially viable methods of preparing zeolites often lead to the formation of impurities. Herein, we present organic-free syntheses of two polymorphs of the small-pore zeolite P (GIS), P1 and P2. Using a combination of adsorption measurements and density functional theory calculations, we show that GIS polymorphs are selective adsorbents for H2O relative to other light gases (e.g., H2, N2, CO2). Our findings refute prior theoretical studies postulating that GIS-type zeolites are excellent materials for CO2 separation/sequestration. We also show that P2 is significantly more thermally stable than P1, which broadens the operating conditions for GIS-type zeolites in commercial applications and opens new avenues for exploring their potential use in processes such as catalysis. [ABSTRACT FROM AUTHOR]

Presents an interfacial area ratio (IAR) model for the prediction of diffusion coefficients as a function of the degree of water saturation. Definition of tortuosity factor in the IAR model; Factor that affects diffusion behavior in unsaturated media; Diffusion coefficients for conservative solutes as a function of water content.

Adsorption cooling, structure defects, fluorocarbon refrigerants, porous covalent organic polymers Keywords: adsorption cooling; structure defects; fluorocarbon refrigerants; porous covalent organic polymers EN adsorption cooling structure defects fluorocarbon refrigerants porous covalent organic polymers 17894 17894 1 08/05/21 20210809 NES 210809 B Defekthaltige kovalente organische Polymere b sind vielversprechend für adsorptionsbasierte Kühlanwendungen. Innentitelbild: Porous Covalent Organic Polymers for Efficient Fluorocarbon-Based Adsorption Cooling (Angew. [Extracted from the article]

In their Research Article on page 18037, Guillaume Maurin, Radha Kishan Motkuri, and co-workers present experimental and computational evidence that mesoporous defects in the framework play a key role for the unique overall linear-shaped R134a adsorption isotherm and the exceptional adsorption uptake. Inside Cover: Porous Covalent Organic Polymers for Efficient Fluorocarbon-Based Adsorption Cooling (Angew. Keywords: adsorption cooling; structure defects; fluorocarbon refrigerants; porous covalent organic polymers EN adsorption cooling structure defects fluorocarbon refrigerants porous covalent organic polymers 17750 17750 1 08/05/21 20210809 NES 210809 B Defective covalent organic polymers b are promising for adsorption-based cooling applications. [Extracted from the article]

Invited for the cover of this issue are the groups of R. K. Motkuri and J. D. Rimer at the Pacific Northwest National Laboratory and University of Houston, respectively. The image depicts bulk sorbents that can be used for separations, a microscopic image of a zeolite crystal framework, and an individual pore operating as a size-exclusion sieve. Read the full text of the article at . [ABSTRACT FROM AUTHOR]

New approaches to tailor the synthesis of zeolite polymorphs can lead to breakthroughs in applications spanning from separations to adsorption. A comparison of small ‐ pore zeolite GIS polymorphs P1 and P2 revealed marked differences in their thermal stability. Moreover, adsorption experiments and DFT studies collectively showed that GIS polymorphs are promising materials for selective separation of small molecules. More information can be found in the Full Paper by R. K. Motkuri, J. D. Rimer et al. on page 16078 ff. [ABSTRACT FROM AUTHOR]