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The structures and properties of nano-XNH2 (X = C, Si, Ge, and Sn) are explored using Density Functional Theory (DFT). Elastic strain and width are introduced to investigate the nano-XNH2 nanosheets and nanoribbons. First, their structural parameters and lattice constants are investigated by using quadratic curve fitting methods. Second, the regulation of bandgap with the change in the elastic strain and width is investigated. The theoretical calculations show that the bandgaps of these materials can be easily modulated. Therefore, nano-XNH2 has great potential applications in stress sensors and electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Orthogonal signal-division multiplexing (OSDM) is an attractive alternative to conventional orthogonal frequency-division multiplexing (OFDM) due to its enhanced ability in peak-to-average power ratio (PAPR) reduction. Combining OSDM with multiple-input multiple-output (MIMO) signaling has the potential to achieve high spectral and power efficiency. However, a direct channel equalization in this case incurs a cubic complexity, which may be expensive for practical use. To solve the problem, low-complexity per-vector and block equalization algorithms of MIMO-OSDM are proposed in this paper for time-invariant and time-varying channels, respectively. By exploiting the channel matrix structures, these algorithms have only a linear complexity in the transformed domain. Simulation results demonstrate their validity and the related performance comparisons. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) stand out as remarkable materials renowned for their exceptionally high surface area and large number of pores, making them invaluable for diverse sensing applications including gas, biomedical, chemical, and optical sensing. Traditional methods of molecule infusion and release often involve a large number of crystals with varying shapes and sizes, leading to averaged outcomes across a heterogeneous crystal population. In this study, we present continuous monitoring of the infusion and release dynamics of model drug molecules, specifically vitamin B12, within individual Tb-mesoMOF crystals. Our findings underscore the critical influence of crystal size and shape on the infusion and diffusion processes and corresponding color change, underscoring the necessity to account for these factors in the design of large-scale systems. Leveraging optical microscopy, we employed a histogram-based algorithm for image processing, enabling automated tracking of diffusion phenomena. This investigation offers crucial insights into the dynamics of these processes, laying the groundwork for optimizing parameters in future sensing systems. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are man-made environmental contaminants causing increasing global concern due to their adverse effect on environmental and human health. Conventional treatment methods are ineffective in removing short-chain PFAS because they are persistent and recalcitrant to treatment. This study evaluated the performance of a structurally-tunable and chemically-stable porous organic polymer (POP) for PFAS removal under realistic environmental conditions. The POP demonstrated an exceptionally high removal efficiency (>95%) within 15 min when the initial PFAS concentration was approximately 400 ng/L. The adsorption of PFAS on the POP was not significantly affected by changes in solution pH within the range of 5–9. The common co-contaminants in water competed with short-chain PFAS for active sites during the adsorption process following the order of natural organic matter (NOM), long-chain PFAS, and Cl−. The Freundlich-type model could predict the multicomponent interactions well with a R2 value above 0.91. The spent POP was effectively regenerated using a mixture of the 10% NaCl and 30% methanol solution and the PFAS removal maintained at 90% through five adsorption and desorption cycles. The characteristics of the designed POP make it a highly promising and stable absorbent. It enables fast and effective removal of short-chain PFAS. [Display omitted] • Cationic POP shows a fast adsorption rate and a high capacity for PFAS removal. • The designed POP maintained above 85% removal for PFBA at a pH range of 5–9. • The effect of the co-contaminants on PFBA removal followed the order of HA > PFOS > Cl−. • PFAS removal maintained at 90% in five consecutive adsorption/regeneration cycles. [ABSTRACT FROM AUTHOR]

Zn 1-x Fe x Se thin films are synthesized for photoelectrochemical cell application using the simple and cost-effective potentiostatic electrodeposition method. The Fe2+ ions are varied from 10 to 40% concerning Zn. The Zn2+ atoms in ZnSe crystals replaced by Fe2+ ions and studied the optical, morphological, structural, photoluminescence and photoelectrochemical cell characteristics of the Zn 1-x Fe x Se based composite. The different analytical tools are used to investigate the properties of Zn 1-x Fe x Se based composite. Wettability studies of thin films are investigated using contact angle meter. The EIS technique is used to study the electrochemical properties. Photoelectrochemical cell properties are investigated using the J-V characteristic study. The variation in Fe2+ ions is responsible for the change in crystal size and morphology. Hence differences are observed in corresponding photoluminescence and photoelectrochemical cell performance. [ABSTRACT FROM AUTHOR]

The selective removal of the β‐emitting pertechnetate ion (99TcO4−) from nuclear waste streams is technically challenging. Herein, a practical approach is proposed for the selective removal of 99TcO4− (or its surrogate ReO4−) under extreme conditions of high acidity, alkalinity, ionic strength, and radiation field. Hollow porous N‐doped carbon capsules loaded with ruthenium clusters (Ru@HNCC) are first prepared, then modified with a cationic polymeric network (R) containing imidazolium‐N+ units (Ru@HNCC‐R) for selective 99TcO4− and ReO4− binding. The Ru@HNCC‐R capsules offer high binding affinities for 99TcO4−/ReO4− under wide‐ranging conditions. An electrochemical redox process then transforms adsorbed ReO4− to bulk ReO3, delivering record‐high removal capacities, fast kinetics, and excellent long‐term durability for removing ReO4− (as a proxy for 99TcO4−) in a 3 m HNO3, simulated nuclear waste‐Hanford melter recycle stream and an alkaline high‐level waste stream (HLW) at the U.S. Savannah River Site (SRS). In situ Raman and X‐ray absorption spectroscopy (XAS) analyses showed that adsorbed Re(VII) is electrocatalytically reduced on Ru sites to a Re(IV)O2 intermediate, which can then be re‐oxidized to insoluble Re(VI)O3 for facile collection. This approach overcomes many of the challenges associated with the selective separation and removal of 99TcO4−/ReO4− under extreme conditions, offering new vistas for nuclear waste management and environmental remediation. [ABSTRACT FROM AUTHOR]

Seawater contains uranium at a concentration of ≈3.3 ppb, thus representing a rich and sustainable nuclear fuel source. Herein, an adsorption–electrocatalytic platform is developed for uranium extraction from seawater, comprising atomically dispersed indium anchored on hollow nitrogen‐doped carbon capsules functionalized with flexible amidoxime moieties (In–Nx–C–R, where R denotes amidoxime groups). In–Nx–C–R exhibits excellent uranyl capture properties, enabling a uranium removal rate of 6.35 mg g−1 in 24 h, representing one of the best uranium extractants reported to date. Importantly, In–Nx–C–R demonstrates exceptional selectivity for uranium extraction relative to vanadium in seawater (8.75 times more selective for the former). X‐ray absorption spectroscopy (XAS) reveals that the amidoxime groups serve as uranyl chelating sites, thus allowing selective adsorption over other ions. XAS and in situ Raman results directly indicate that the absorbed uranyl can be electrocatalytically reduced to an unstable U(V) intermediate, then re‐oxidizes to U(VI) in the form of insoluble Na2O(UO3·H2O)x for collection, through reversible single electron transfer processes involving InNx sites. These results provide detailed mechanistic understanding of the uranium extraction process at a molecular level. This work provides a roadmap for the adsorption–electrocatalytic extraction of uranium from seawater, adding to the growing suite of technologies for harvesting valuable metals from the earth's oceans. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Zr(IV)-based MOF with high-density free carboxylic groups was constructed. • The MOF demonstrates high stability and excellent uranium removal performance. • Dynamic sorption tests highlight its potential for treating radioactive wastewater. • The mechanism for its excellent ability to adsorb U(VI) was investigated. The extraction of uranium from aqueous environments, including the ocean and radioactive wastewater, represents a significant challenge with profound implications for energy resources and environmental remediation. This work presents the design and synthesis of a novel highly stable carboxylated metal–organic framework, BUT-12-3COOH, which achieves excellent U(VI) extraction ability from water. BUT-12-3COOH features high-density free carboxylic groups, exceptional chemical stability, fast kinetics, and high adsorption capacity for U(VI). Dynamic sorption experiments further demonstrated the potential of BUT-12-3COOH in treating real radioactive wastewater. The mechanisms for the U(VI) capture of BUT-12-3COOH are investigated through the combination of EDS, FT-IR, and XPS analysis. The results of this study underscore the promising utility of BUT-12-3COOH as an effective sorbent for extracting radionuclides from environmental specimens and liquid nuclear waste streams. [ABSTRACT FROM AUTHOR]

Al-promoted mesostructured sulfated zirconia (Al-MSZ-5) has been successfully synthesized from the template of triblock polymer surfactant (P123) in aqueous solution. Mesostructured Al-MSZ-5 shows high thermal stability, and it can preserve its characteristic mesostructures until calcination at 650 °C. In contrast, the mesostructure of mesoporous sulfated zirconia (MSZ-5) will be destroyed during calcination at 600 °C. Catalytic data for n-butane isomerization show that the Al-MSZ-5 exhibits higher catalytic activity and better stability than both MSZ-5 and conventional Al-promoted sulfated zirconia (Al-SZ). The Al-MSZ-5 sample was characterized by XRD, bright-field and dark-field TEM images, N2 adsorption isotherms, NMR, TG–DTA, IR, and numerous other techniques. The results suggest that Al-MSZ-5 has worm-like mesopores, and that the mesostructured walls contain tetragonal crystalline ZrO2. Such unique structural features might be responsible for the observed large surface area, high catalytic activity for n-butane isomerization, and high thermal stability of mesostructured Al-MSZ-5. [Copyright &y& Elsevier]

Coupling appropriate semiconductor nanoparticles with massive surface-area support has become a promising but challenging strategy to photocatalyst design for enhanced photocatalytic activity in environmental cleaning applications, owing to the severe aggregation issues of nanoparticles. Herein, the atomic layer deposition (ALD) approach was applied to uniformly disperse ultrafine Cu 2 O nanoparticles (5–10 nm) on metal-organic frameworks without aggregation, forming NH 2 -MIL-101(Fe)/Cu 2 O nanocomposite photocatalysts. The Cu 2 O mass within the nanocomposites can be well controlled by merely adjusting the ALD cycles. The optimal NH 2 -MIL-101(Fe)/Cu 2 O displays a high photodegradation efficiency of 92% for RhB and excellent stability under visible light. The reaction kinetics and photocurrent response experimental results reveal that the optimal NH 2 -MIL-101(Fe)/Cu 2 O photocatalyst exhibits effective charge separation/transfer and suppressed recombination rate of charge carriers, which will significantly increase the solar light utilization efficiency and photocatalytic activity. We believe the presented photocatalyst synthesis strategy here can be generalized to construct other photocatalysts for various photocatalytic applications. [ABSTRACT FROM AUTHOR]

Preorganization is a basic design principle used by nature that allows for synergistic pathways to be expressed. Herein, a full account of the conceptual and experimental development from randomly distributed functionalities to a convergent arrangement that facilitates cooperative binding is given, thus conferring exceptional affinity toward the analyte of interest. The resulting material with chelating groups populated adjacently in a spatially locked manner displays up to two orders of magnitude improvement compared to a random and isolated manner using uranium sequestration as a model application. This adsorbent shows exceptional extraction efficiencies, capable of reducing the uranium concentration from 5 ppm to less than 1 ppb within 10 min, even though the system is permeated with high concentrations of competing ions. The efficiency is further supported by its ability to extract uranium from seawater with an uptake capability of 5.01 mg g−1, placing it among the highest‐capacity seawater uranium extraction materials described to date. The concept presented here uncovers a new paradigm in the design of efficient sorbent materials by manipulating the spatial distribution to amplify the cooperation of functions. [ABSTRACT FROM AUTHOR]

• Boosted activity by introducing the amine group in a porous pyridinium framework. • CO 2 activated by the amine group facilitating the subsequent catalytic steps. • Superior catalytic performances even under ambient conditions. Multifunctional catalysts derived from the integration of discrete catalytic partners in a confined space represent an important approach to emulate some of the design philosophies of enzymes. In an effort to design concepts for highly active catalysts for CO 2 transformations, we synthesize and contrast the performance of two porous pyridinium frameworks. The activity is found to be significantly amplified by the introduction of the amine group on the ortho position of the pyridinium moieties. The resulting catalyst is capable of highly active and selective cycloaddition of aziridines with CO 2 to 5-substituted-2-oxazolidinone, even under ambient conditions (1 bar, 22 °C). Its high activity originates from CO 2 activation by the pendant amine group in the vicinity of the active species, which facilitates the subsequent catalytic steps. [ABSTRACT FROM AUTHOR]

Albeit metal-organic framework (MOF) composites have been extensively explored, reducing the size and dimensions of various contents within the composition, to the nanoscale regime, has recently presented unique opportunities for enhanced properties with the formation of MOF-based nanocomposites. Many distinctive strategies have been used to fabricate these nanocomposites such as through the introduction of nanoparticles (NPs) into a MOF precursor solution or vice versa to achieve a core-shell or heterostructure configuration. As such, MOF-based nanocomposites offer seemingly limitless possibilities and promising solutions for the vast range of applications across biomedical disciplines especially for improving in vivo implementation. In this review, we focus on the recent development of MOF-based nanocomposites, outline their classification according to the type of integrations (NPs, coating materials, and different MOF-derived nanocomposites), and direct special attention towards the various approaches and strategies employed to construct these nanocomposites for their prospective utilization in biomedical applications including biomimetic enzymes and photo, chemo, sonodynamic, starvation and hyperthermia therapies. Lastly, our work aims to highlight the exciting potential as well as the challenges of MOF-based nanocomposites to help guide future research as well as to contribute to the progress of MOF-based nanotechnology in biomedicine. • A review on recent strategies to develop MOF-based nanocomposites. • Focus on the biomedical applications including biocatalytic, photo, chemo, sonodynamic, starvation and hyperthermia therapies. • Discussion of the synergistic effects of guest functional materials and MOFs. • Challenges and prospects of MOF-based nanotechnology for biomedical utilization. [ABSTRACT FROM AUTHOR]

The energy costs associated with the separation and purification of industrial commodities, such as gases, fine chemicals and fresh water, currently represent around 15 per cent of global energy production, and the demand for such commodities is projected to triple by 2050 (ref. 1). The challenge of developing effective separation and purification technologies that have much smaller energy footprints is greater for carbon dioxide (CO2) than for other gases; in addition to its involvement in climate change, CO2 is an impurity in natural gas, biogas (natural gas produced from biomass), syngas (CO/H2, the main source of hydrogen in refineries) and many other gas streams. In the context of porous crystalline materials that can exploit both equilibrium and kinetic selectivity, size selectivity and targeted molecular recognition are attractive characteristics for CO2 separation and capture, as exemplified by zeolites 5A and 13X (ref. 2), as well as metal-organic materials (MOMs). Here we report that a crystal engineering or reticular chemistry strategy that controls pore functionality and size in a series of MOMs with coordinately saturated metal centres and periodically arrayed hexafluorosilicate (SiF62−) anions enables a 'sweet spot' of kinetics and thermodynamics that offers high volumetric uptake at low CO2 partial pressure (less than 0.15 bar). Most importantly, such MOMs offer an unprecedented CO2 sorption selectivity over N2, H2 and CH4, even in the presence of moisture. These MOMs are therefore relevant to CO2 separation in the context of post-combustion (flue gas, CO2/N2), pre-combustion (shifted synthesis gas stream, CO2/H2) and natural gas upgrading (natural gas clean-up, CO2/CH4). [ABSTRACT FROM AUTHOR]

Coordination-driven self-assembly is an effective synthetic tool for the construction of spatially and electronically tunable supramolecular coordination complexes (SCCs), which are useful in various applications. Herein, we report the synthesis of a two-dimensional discrete metalla-rectangle [(η6-p-cymene)4Ru4(C6H2O4)2(2)2](CF3SO3)4 (3) by the reaction of a dinuclear half-sandwich ruthenium (II) complex [Ru2(η6-p-cymene)2(C6H2O4)Cl2] (1) and bis-pyridyl amide linker (2) in the presence of AgO3SCF3. This cationic ruthenium metalla-rectangle (3) has been isolated as its triflate salt and characterized by analytical techniques including elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), carbon nuclear magnetic resonance spectroscopy (13C-NMR), 1H-1H correlation spectroscopy (COSY), 1H-1H nuclear Overhauser effect spectroscopy (NOESY), diffusion ordered spectroscopy (DOSY), and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). Significantly, the 2D cationic ruthenium metalla-rectangle showed better anticancer activity towards three different cell lines (A549, Caki-1 and Lovo) as compared with the parent ruthenium complex (1) and the commercially used drug, cisplatin. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are an emerging class of functional nanostructures with intriguing properties, due to their unprecedented combination of high crystallinity, tunable pore size, large surface area, and unique molecular architecture. The range of properties characterized in COFs has rapidly expanded to include those of interest for numerous applications ranging from energy to environment. Here, a background overview is provided, consisting of a brief introduction of porous materials and the design feature of COFs. Then, recent advancements of COFs as a designer platform for a plethora of applications are emphasized together with discussions about the strategies and principles involved. Finally, challenges remaining for this type material for real applications are outlined. Covalent organic frameworks (COFs) are porous crystalline polymers with tunable composition and structural architecture, enabling precise control over functionality, density, and spatial arrangement. This universal control makes them a particularly promising platform for task‐led design. Recent advancements of COFs for numerous applications are reviewed and the challenges and opportunities associated with processing and large‐scale synthesis are discussed. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are an emerging class of functional nanostructures with intriguing properties, due to their unprecedented combination of high crystallinity, tunable pore size, large surface area, and unique molecular architecture. The enormous possible design space available within COFs provides virtually unlimited room for imagination, allowing designed incorporation of different functionalities. In article number 1801410, Qi Sun, Shengqian Ma, and co‐workers review the recent advancements of COFs for numerous applications. [ABSTRACT FROM AUTHOR]