Sb3+/Sm3+ Codoped Cs2NaScCl6 All-Inorganic Double Perovskite: Blue Emission of Self-Trapped Excitons and Red-Emission via Energy Transfer.

The lead-free halide perovskites possess nontoxicity and excellent chemical stability, whereas relatively weak luminescence intensity limits their potential in practical applications. Therefore, strengthening the luminescence intensity and expanding application fields are urgent tasks for the development of lead-free halide perovskites. In this paper, antimony-doped Cs2NaScCl6 crystals synthesized by a solvothermal method emit bright, deep blue photoluminescence at 447 nm. The photoluminescence (PL), photoluminescence excitation (PLE), and absorption spectra demonstrate that Sb3+ doping effectively activate the intrinsic "dark self-trapped exciton (STE)," leading to an impressive photoluminescence quantum yield (PLQY) value of 78.31% for 1% Sb3+ doping. Furthermore, the luminescence intensity remains above 92% compared with the fresh sample without secondary phases detected even after 90 days under environmental conditions. To expand the emission spectra, rare-earth Sm3+ is further incorporated into Cs2NaScCl6:1% Sb3+ crystals. The results show that Sb ions not only enhance intrinsic STE luminescence but also serve as sensitizers to boost the red-light emission of Sm3+, leading to a significant 500-fold increase in red emission intensity. Finally, the PLQY reaches a stunning 86.78%. These findings provide valuable insights in the design of Sb ion-doped lead-free double perovskites, broadening the application fields in various optoelectronic devices.

Efficient conversion of propane in a microchannel reactor at ambient conditions.

The oxidative dehydrogenation of propane, primarily sourced from shale gas, holds promise in meeting the surging global demand for propylene. However, this process necessitates high operating temperatures, which amplifies safety concerns in its application due to the use of mixed propane and oxygen. Moreover, these elevated temperatures may heighten the risk of overoxidation, leading to carbon dioxide formation. Here we introduce a microchannel reaction system designed for the oxidative dehydrogenation of propane within an aqueous environment, enabling highly selective and active propylene production at room temperature and ambient pressure with mitigated safety risks. A propylene selectivity of over 92% and production rate of 19.57 mmol mCu-2 h-1 are simultaneously achieved. This exceptional performance stems from the in situ creation of a highly active, oxygen-containing Cu catalytic surface for propane activation, and the enhanced propane transfer via an enlarged gas-liquid interfacial area and a reduced diffusion path by establishing a gas-liquid Taylor flow using a custom-made T-junction microdevice. This microchannel reaction system offers an appealing approach to accelerate gas-liquid-solid reactions limited by the solubility of gaseous reactant.

Photoenzymatic CO2 Reduction Dominated by Collaborative Matching of Linkage and Linker in Covalent Organic Frameworks.

Artificial photoenzymatic systems based on covalent organic frameworks (COFs) provide an interesting platform for converting CO2 to value-added fuels. However, the dual roles of COFs as photocatalysts and enzyme hosts showcase contradictory preferences for structures, which poses a great challenge for their rational design. Herein, we report the collaborative matching of linkages and linkers in COFs on their ability to exert both photocatalytic activity and enzyme loading, which has been neglected until now. The linkage-dependent linker regulation pattern was elucidated, and the optimal match showed a record-breaking apparent quantum efficiency at 420 nm for photocatalytic cofactor regeneration of 13.95% with a high turnover frequency of 5.3 mmol g-1 h-1, outperforming other reported crystalline framework photocatalysts. Moreover, theoretical calculations and experiments revealed the mechanism underlying the effects of matching the linkage and linker on exciton dissociation and charge migration in photocatalysis. This newfound understanding enabled the construction of COFs with both high photoactivity and large pores closer in size to the formate dehydrogenase, achieving high loading capacity and a suitable confinement effect. Remarkably, the artificial photoenzymatic system constructed according to optimal linkage-linker matching exhibited highly efficient CO2 reduction, yielding formic acid with a specific activity as high as 1.46 mmol g-1 catalyst h-1 and good reusability, paving the way for sustainable CO2 conversion driven by visible light.

A general neural network model co-driven by mechanism and data for the reliable design of gas-liquid T-junction microdevices.

In recent years, many models have been developed to describe the gas-liquid microdispersion process, which mainly rely on mechanistic analysis and may not be universally applicable. In order to provide a more comprehensive model and, most significantly, to provide a model for design, we have established a general database of microbubble generation in T-junction microdevices, including 854 data points from 12 pieces of literature. A neural network model that combines mechanistic and data modeling is developed. By transfer learning, more accurate results can be obtained. Additionally, we have proposed a design method that enables a relative deviation of less than 5% from the expected bubble size. A new device was designed and prepared to confirm the reliability of the method, which can prepare smaller bubbles than other common T-junction devices. In this way, a general and universal database and model are established and a design method for a gas-liquid T-junction microreactor is developed.

Green and Rapid Synthesis of Acridine-Functionalized Covalent Organic Polymers for Photocatalysis by Combining Sonochemistry and Ion Induction.

Covalent organic polymers (COPs) are powerful candidates for achieving the visible-light-driven degradation of organic pollutants by virtue of structural designability, but their synthesis relies on harmful reagents and high temperatures, which weakens their associated green merits. Here, we report a novel strategy for combining sonochemistry with ion induction for the rapid preparation of acridine-functionalized COPs in green and mild aqueous solutions with tunable high yields of 80 to 90%. Photochemical studies reveal the ability of these COPs to harvest visible light and their sufficient conduction potentials for generating superoxide radicals. Furthermore, the photodegradation of methylene blue confirms the good photocatalytic activity and reusability of the zinc ion-based acridine-functionalized COP, which achieves 90.8% removal in 150 min and retains 82.5% activity after 5 reuse cycles, with a rate constant of up to 3.2 times that of commercial titanium dioxide nanoparticles. This strategy paves the way for the green, rapid, and mild synthesis of acridine-functionalized COPs, enabling visible light photocatalytic degradation for water treatment and energy conversion to advance in a thoroughly environmentally friendly and cost-effective manner.

High-efficiency uranium extraction from seawater by low-cost natural protein hydrogel.

Utilization of uranium resource in seawater are highly possible to meet the growth demands for the sustainable development of nuclear energy industry. Bio-adsorbents exhibit high performance in terms of adsorption selectivity, equilibrium speed, and environmental friendliness, while the high fabrication cost hinders their practical application. In this study, a low-cost soy protein isolate (SPI) is used to fabricate adsorbent named SPI hydrogel for uranium extraction. This is the first report on applying bio-adsorbents derived from low-cost natural proteins for uranium extraction. The SPI hydrogel showed high uranium adsorption capacity of 53.94 mg g-1 in simulated nuclear wastewater and 5.29 mg g-1 is achieved in natural seawater, which is higher than all currently available adsorbents based on non-modified natural biomolecules. The amino and oxygen-containing groups are identified as the functional groups for uranyl binding by providing four oxygen and two nitrogen atoms to form equatorial coordination with uranyl, which guarantees the high binding selectivity and affinity to uranyl ions. The low cost for accessing the raw material together with the environmental friendliness, high salt tolerance, high uranium adsorption ability, and high selectivity to uranium, make SPI hydrogel a promising adsorbent for uranium extraction from seawater and nuclear wastewater.

Active and stable alcohol dehydrogenase-assembled hydrogels via synergistic bridging of triazoles and metal ions.

Biocatalysis is increasingly replacing traditional methods of manufacturing fine chemicals due to its green, mild, and highly selective nature, but biocatalysts, such as enzymes, are generally costly, fragile, and difficult to recycle. Immobilization provides protection for the enzyme and enables its convenient reuse, which makes immobilized enzymes promising heterogeneous biocatalysts; however, their industrial applications are limited by the low specific activity and poor stability. Herein, we report a feasible strategy utilizing the synergistic bridging of triazoles and metal ions to induce the formation of porous enzyme-assembled hydrogels with increased activity. The catalytic efficiency of the prepared enzyme-assembled hydrogels toward acetophenone reduction is 6.3 times higher than that of the free enzyme, and the reusability is confirmed by the high residual catalytic activity after 12 cycles of use. A near-atomic resolution (2.1 Å) structure of the hydrogel enzyme is successfully analyzed via cryogenic electron microscopy, which indicates a structure-property relationship for the enhanced performance. In addition, the possible mechanism of gel formation is elucidated, revealing the indispensability of triazoles and metal ions, which guides the use of two other enzymes to prepare enzyme-assembled hydrogels capable of good reusability. The described strategy can pave the way for the development of practical catalytic biomaterials and immobilized biocatalysts.

Ultrafast extraction of uranium from seawater using photosensitized biohybrid system with bioinspired cascaded strategy.

The highly effective utilization of uranium resources in global seawater is a viable method to satisfy the rising demands for fueling nuclear energy industry. Herein, inspired by the multi-mechanisms of the marine bacteria for uranium immobilization, CdS nanoparticles are deposited on the cell of marine bacterial strain Bacillus velezensis UUS-1 to create a photosensitized biohybrid system UUS-1/CdS. This system achieves high uranium extraction efficiency using a cascaded strategy, where the bacterial cells guarantee high extraction selectivity and the photosensitive CdS nanoparticles realize cascading photoreduction of high soluble U(VI) to low soluble U(IV) to enhance extraction capacity. As one of the fastest-acting adsorbents in natural seawater, a high extraction capacity for uranium of 7.03 mg g-1 is achieved with an ultrafast extraction speed of 4.69 mg g-1 d-1. The cascaded strategy promisingly improves uranium extraction performance and pioneers a new direction for the design of adsorbents to extract uranium from seawater.

Recycling of Cofactors in Crude Enzyme Hydrogels as Co-immobilized Heterogeneous Biocatalysts for Continuous-Flow Asymmetric Reduction of Ketones.

Flow biocatalysis involving oxidoreductase is limited by the difficulty in recycling expensive cofactors. In this study, an enzyme-rich hydrogel monolithic microreactor was developed via in situ microfluidic assembly of inexpensive crude enzymes. This porous gel biocatalyst exhibited good tethering functions to nicotinamide cofactors; thus, they were retained by the hydrogel to controllably form a novel heterogeneous biocatalyst with self-sufficient cofactors. The flow asymmetric production of a chiral alcohol in this cofactor-entrapped gel microreactor achieved >99 % enantioselectivity and a high space-time yield of 46.3 g L-1 h-1 at 94.8 % conversion. Moreover, the turnover number of cofactors reached as high as 4800 after continuous operation of 160 reactor volumes, realizing significantly higher utilization of the cofactors compared with many reported strategies. Furthermore, this engineered heterogeneous biocatalyst exhibited improved performance in terms of product tolerance and storage stability, paving the way for a green, cost-effective, and sustainable continuous-flow production of enantiopure alcohols.

Unveiling the mechanism of methylcellulose-templated synthesis of Al2O3 microspheres with organic solvents as swelling agents in microchannel.

Herein, we report a systematic investigation of the preparation of large-pore-volume Al2O3 microspheres using a complex synthesis system with methylcellulose (MC) as the template and gelation initiator and organic solvents as the swelling agent and carrier medium under the flow characteristics of a coaxial microchannel. The adsorption of MC micelles on boehmite colloidal nanoparticles (NPs) was proven and determined by interfacial tension measurements, dynamic light scattering, and cryogenic transmission electron microscopy. Isothermal titration calorimetry demonstrated that the adsorption process was caused by nonspecific hydrophobicity; one binding site was involved, and the affinity constant was 1060 M-1. When the MC:NPs mass ratio exceeded 0.1, the template-NP bridged each other to form large aggregates, thereby forming large mesopores and enhancing the gelation speed. Alkanes, alcohols, and amines were applied to further enhance the porosity, and the swelling capacities were investigated experimentally and theoretically. Amines were efficient swelling agents owing to their excellent ability to swell MC micelles and insert into the acid colloid network. The coaxial microchannel was subjected to molding; this process significantly influenced the morphology and textural properties owing to the internal circulation during droplet formation. When trihexylamine with suitable steric hindrance, alkalinity, and polarity was used as the swelling agent, the microspheres exhibited an optimal specific surface area of 403 m2/g and a pore volume of 1.85 cm3/g.

Determination of Time-Evolving interfacial tension and ionic surfactant adsorption kinetics in microfluidic droplet formation process.

Surfactant adsorption plays an important role in microfluidics, which can be investigated by the dynamic evolution of interfacial tension. A differential pressure-based method is proposed to understand the basic laws of time-evolving interfacial tension and adsorption kinetics of ionic surfactants during the microfluidic droplet formation processes. Instantaneous flow rates and flow resistances are precisely analyzed based on auto-recognized microscopic images and the waveform of differential pressure, and the interfacial tension is determined from the Young-Laplace equation with a time resolution of 1/60 s. The concentration of surfactant at the liquid-liquid interface is obtained according to the Frumkin adsorption model, leading to an in-depth understanding of the adsorption rates and the apparent mass transfer rates of surfactants. The surfactant adsorption is demonstrated to obey the kinetic-controlled adsorption mechanism and therefore a measurement method for the adsorption rate constant is created to understand the kinetic characteristics of small-molecule ionic surfactants.

Halogen hydrogen-bonded organic framework (XHOF) constructed by singlet open-shell diradical for efficient photoreduction of U(VI).

Synthesis of framework materials possessing specific spatial structures or containing functional ligands has attracted tremendous attention. Herein, a halogen hydrogen-bonded organic framework (XHOF) is fabricated by using Cl- ions as central connection nodes to connect organic ligands, 7,7,8,8-tetraaminoquinodimethane (TAQ), by forming a Cl-···H3 hydrogen bond structure. Unlike metallic node-linked MOFs, covalent bond-linked COFs, and intermolecular hydrogen bond-linked HOFs, XHOFs represent a different kind of crystalline framework. The electron-withdrawing effect of Cl- combined with the electron-rich property of the organic ligand TAQ strengthens the hydrogen bonds and endows XHOF-TAQ with high stability. Due to the production of excited electrons by TAQ under light irradiation, XHOF-TAQ can efficiently catalyze the reduction of soluble U(VI) to insoluble U(IV) with a capacity of 1708 mg-U g-1-material. This study fabricates a material for uranium immobilization for the sustainability of the environment and opens up a new direction for synthesizing crystalline framework materials.

GEP-EpiSeeker: a gene expression programming-based method for epistatic interaction detection in genome-wide association studies.

BACKGROUND: Identification of epistatic interactions provides a systematic way for exploring associations among different single nucleotide polymorphism (SNP) and complex diseases. Although considerable progress has been made in epistasis detection, efficiently and accurately identifying epistatic interactions remains a challenge due to the intensive growth of measuring SNP combinations. RESULTS: In this work, we formulate the detection of epistatic interactions by a combinational optimization problem, and propose a novel evolutionary-based framework, called GEP-EpiSeeker, to detect epistatic interactions using Gene Expression Programming. In GEP-EpiSeeker, we propose several tailor-made chromosome rules to describe SNP combinations, and incorporate Bayesian network-based fitness evaluation into the evolution of tailor-made chromosomes to find suspected SNP combinations, and adopt the Chi-square test to identify optimal solutions from suspected SNP combinations. Moreover, to improve the convergence and accuracy of the algorithm, we design two genetic operators with multiple and adjacent mutations and an adaptive genetic manipulation method with fuzzy control to efficiently manipulate the evolution of tailor-made chromosomes. We compared GEP-EpiSeeker with state-of-the-art methods including BEAM, BOOST, AntEpiSeeker, MACOED, and EACO in terms of power, recall, precision and F1-score on the GWAS datasets of 12 DME disease models and 10 DNME disease models. Our experimental results show that GEP-EpiSeeker outperforms comparative methods. CONCLUSIONS: Here we presented a novel method named GEP-EpiSeeker, based on the Gene Expression Programming algorithm, to identify epistatic interactions in Genome-wide Association Studies. The results indicate that GEP-EpiSeeker could be a promising alternative to the existing methods in epistasis detection and will provide a new way for accurately identifying epistasis.

Formation Mechanism of Monodispersed Polysilsesquioxane Spheres in One-Step Sol-Gel Method.

Monodispersed polysilsesquioxane (PSQ) spheres with diameters from hundreds of nanometers to several microns have been successfully synthesized; however, the knowledge of their formation mechanism still lags behind. Herein, with methyltrimethoxysilane and 3-mercaptopropyl trimethoxysilane as model silicon sources, the formation process of PSQ spheres in the one-step sol-gel method was revealed for the first time by monitoring the time evolution of particle morphology, size, and size distribution via transmission electron microscopy and dynamic light scattering. A four-stage formation mechanism was proposed: rapid hydrolysis of organic silicon source and subsequent oligomer micelle nucleation, fast growing of nuclei particles and formation of their aggregates, followed by a further relatively fast growth of dispersed particles, and finally a slow growth to form monodispersed PSQ spheres. Due to the reversibility of hydrolysis and condensation reactions, thermodynamically unstable particles gradually transformed to hydrolytic monomers/oligomers and then regrew on the thermodynamically stable particles until the concentration of hydrolytic oligomers reached the dissolution equilibrium in the alkaline reaction solution. The variation of growth rate during the formation process and the effects of NH4OH concentration on the yield and particle size were investigated to facilitate analyses and understanding of the formation mechanism.

One-Pot Synthesis of Glucose-Derived Carbon Coated Ni3S2 Nanowires as a Battery-Type Electrode for High Performance Supercapacitors.

We report a novel Ni3S2 carbon coated (denoted as NCC) rod-like structure prepared by a facile one-pot hydrothermal method and employ it as a binder free electrode in supercapacitor. We coated carbon with glucose as carbon source on the surface of samples and investigated the suitable glucose concentration. The as-obtained NCC rod-like structure demonstrated great performance with a huge specific capacity of 657 C g-1 at 1 A g-1, preeminent rate capability of 87.7% retention, the current density varying to 10 A g-1, and great cycling stability of 76.7% of its original value through 3500 cycles, which is superior to the properties of bare Ni3S2. The result presents a facile, general, viable strategy to constructing a high-performance material for the supercapacitor applications.

Whole-cell biocatalytic synthesis of S-(4-chlorophenyl)-(pyridin-2-yl) methanol in a liquid-liquid biphasic microreaction system.

This work aims to synthesize S-(4-chlorophenyl)-(pyridin-2-yl) methanol (S-CPMA) in a green, economic, and efficient way. In the water-cyclohexane liquid-liquid system, recombinant Escherichia coli (E. coli) was used as a whole-cell catalyst and retained > 60% of its catalytic activity after five reuse cycles. In situ accumulation of the substrate/product in the organic phase effectively improves substrate tolerance and reduces product inhibition and toxicity. Meanwhile, a microreaction system consisting of membrane dispersion and three-dimensional (3D) bending-microchannel was developed to successfully generate droplet swarms with an average diameter of 30 µm. Large specific surface area provided high mass transfer efficiency between phases. While the analogous reaction in a traditional stirred tank required > 270 min to achieve a yield of > 99%, in this biphasic microreaction system, the yield reached 99.6% with a high enantiomeric excess (ee) of > 99% in only 80 min. Efficient synthesis was achieved by reducing the time by 70%.

Determination of Dynamic Interfacial Tension during the Generation of Tiny Droplets in the Liquid-Liquid Jetting Flow Regime.

Liquid-liquid dispersion coupled with droplet formation and mass transfer of surfactants is one of the most typical phenomena in many chemical processes. As in every aspect of this process, the interfacial tension variation caused by the unsaturated adsorption of surfactants on the droplet surface plays an important role. This article focuses on microdroplet formation and the dynamic interfacial behavior of surfactants in the jetting regime. In a capillary embedded step T-junction device, controllable preparation of monodisperse droplets is achieved, and a correlation for predicting droplet sizes is established. A method for measuring the dynamic interfacial tension is provided. Mass transfer coefficients are then calculated for Tween 20 during the droplet formation process by a semiempirical correlation. The results indicate that dynamic interfacial tensions are lower than those obtained when the surfactant is adsorbed to equilibrium. Based on the tip-streaming phenomenon, mass transfer coefficients for Tween 20 can reach up to ∼10-3 m/s, higher than those obtained in coaxial microfluidic devices. All the preliminary results shed light on the nature of droplet formation and will be of significance for application in industrial apparatuses.

Reaction Pathway and Selectivity Control of Tetraethyl Thiuram Disulfide Synthesis with NaHCO3 as a pH Regulator.

The selectivity of a chemical reaction is related to the effective utilization of raw materials as well as the cleanliness and economy of the process. Herein, it has been first proposed to synthesize tetraethyl thiuram disulfide (TETD) with sodium bicarbonate as the pH regulator with a reaction selectivity of ∼100%. The existence of a reaction intermediate, a sodium salt of diethyl dithiocarbamoylsulfenic acid (NaEt2DTCS), has been proved by experiments and theoretical calculations. The results indicate that TETD can not only be generated from NaEt2DTCS oxidized by H2O2 directly, but also from the conjugation of NaEt2DTC and NaEt2DTCS generated in the first stage of oxidation meanwhile. Accordingly, an oxidation reaction pathway has been proposed. The reaction selectivity with NaHCO3 or CO2 as the pH regulator has been compared, and the selectivity control mechanism is discussed. At relatively higher pH values with NaHCO3 as the pH regulator, peroxidation could be almost avoided.

Selective Adsorption of C6, C8, and C10 Linear α-Olefins from Binary Liquid-Phase Olefin/Paraffin Mixtures Using Zeolite Adsorbents: Experiment and Simulations.

The adsorption separation of gaseous olefin/paraffin using porous materials has been extensively studied from both experimental and molecular simulation perspectives, while the adsorption separation of liquid-phase olefin/paraffin has been much less studied. One of the most important reasons for this is that it is difficult to measure the actual adsorption capacity of liquid-phase adsorption separation directly through experiments, and the simulation results of most studies are compared to gas-phase measurements. In this paper, the selective adsorption of linear α-olefins from three binary liquid-phase olefin/paraffin mixtures, 1-hexene/n-hexane (C6), 1-octene/n-octane (C8), and 1-decene/n-decane (C10), by zeolite adsorbents was systematically investigated using batch adsorption experiments and configurational-bias grand canonical Monte Carlo (CB-GCMC) simulations. In the batch experiments, based on the liquid-phase measurement method of the actual adsorption capacity that we developed, a modified commercial 5A zeolite with a relatively large pore volume and surface area was used for adsorption. The results showed that the modified 5A zeolite had larger actual adsorption capacities for C6 and C8 linear α-olefins, which increased by 51% and 56%, respectively, than the standard 5A zeolite that was used in our previous work. The adsorption isotherms of C6, C8, and C10 in the 5A and 13X zeolites were calculated by CB-GCMC simulations. The visualized results of density profiles showed that the olefin molecules were densely distributed at the edge of the zeolite cages and that there were cases where a single molecule was adsorbed over two adjacent cages. The good agreement between the experimental and simulated data proves the completeness of the liquid-phase measurement method that we developed and the reliability of the simulation prediction.