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In nature, living organisms, such as octopuses, cabrito, and frogs, have already evolved admirable adhesive abilities for better movement and predation in response to the surroundings. Inspired by biological structures, researchers have made enormous efforts in developing actuators that can respond to external stimuli, while such adhesive property is very desired, yet there is still limited research in responsive hydrogel actuators. Here, a bilayer actuator with high stretchability and robust interface bonding is presented, which has a smart adhesion and thermoreception function. The system consists of an adhesive passive layer copolymerized of amphoteric ([2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl), SBMA) and acrylic acid (AA), and an active layer hydrogel composed of poly(N-isopropylacrylamide) (PNIPAm) containing polydopamine-modified MXene (P-MXene) and calcium chloride (CaCl2). The coordination of carboxylate and Ca2+at the interface of the two layers enhances the interfacial bonding from 14 to 30 N m–1, which facilitates withstanding large strain and preventing stratification. The resulting hydrogel actuator can bend approximately 360° in a mere 10 s, exhibiting excellent photothermal effect, a large angle bending deformation, and ultrafast photoresponsive ability. As a proof of concept, the photothermal actuators are programmed to present various shapes and grab objects. Importantly, the hydrogel actuator exhibits remarkable adhesion capabilities toward diverse substrates, with a maximum peel force of up to 280 N m–1. Relying on their own adhesion and the photoresponse properties, these flexible adhesion actuators show outstanding gripping capability, enabling them to grip and release objects of different shapes and weights. More interestingly, the hydrogel exhibits a smart adjustable adhesion capability at different temperatures, which enables it as a gripper to recognize temperature signals through real-time different feedback actions based on its own adhesion. This study presents innovative insights into biomimetic hydrogel actuators, providing new opportunities for developing intelligent soft robots with multiple functions.

Shape-programmable hydrogel-based soft actuators that can adaptively respond to external stimuli are of paramount significance for the development of bioinspired aquatic smart soft robots. Herein, we report the design and synthesis of near-infrared (NIR) light-driven hydrogel actuators through in situ photopolymerization of poly(N-isopropylacrylamide) (PNIPAM) hydrogels loaded with metal–organic frameworks (MOFs) onto the surface of the poly(dimethylsiloxane) (PDMS) thin film. The MOFs can not only function as an excellent photothermal nanotransducer but also accelerate the adsorption/desorption of water due to their porous nanostructure, which speeds up the response rate of the actuators. Shape-programmable hydrogel actuators are fabricated by tailoring the patterning of PDMS thin film, and thus different shape-morphing modes such as directional bending and chiral twisting are observed under the NIR light irradiations. As the proof-of-concept demonstrations, an artificial hand, biomimetic mimosa, and flower are conceptualized with light-driven MOF-containing hydrogel actuators. Interestingly, we are able to achieve an octopus-inspired light-driven soft swimmer upon cyclic NIR illumination due to the fast photoresponsiveness of as-prepared hydrogel actuators. This work can offer insights for fabricating programmable and reconfigurable smart aquatic soft actuators, thus shining a light into their potential applications in emerging fields including soft robots, biomedical devices, and beyond.

With growing industrialization, the dye industries release a huge quantity of dye-contaminated water to the surrounding environment which affects the agricultural land and crop productivity. The present study was carried out to apply the wheat straw-pyrolyzed biochar to the dye industry wastewater to reduce the chemical oxygen demand (COD) and other toxic metals. For the application of biochar, wastewater samples were collected and analyzed for various parameters, namely, pH, temperature, total dissolved solids, electrical conductivity, sulfate, sodium, nitrate, calcium, potassium, chloride, and chemical oxygen demand. All the results were below the National Environmental Quality Standards of Pakistan (Pak-NEQs 1997/2008) and US-EPA except COD (i.e., 236 mg/L). For the reduction of COD, the wastewater samples were treated with wheat straw biochar through a group of experiments under variable adsorbent dosage and contact time. The biochar application, i.e., 0.5, 1.0, 1.5, 2.0, and 2.5 in g/L, removed the COD up to 19.5, 34, 44.5, 56, and 62% with a significance of p< 0.05. The results stated that COD was reduced ~ 62% (up to 90 mg/L) with 2.5 g of adsorbent for 2-h contact time, and found below the permissible limit of Pak-NEQs (1997/2008); that is, 150 mg/L was considered as an optimum dose. Findings from the present study suggested that biochar derived from agro-waste could be a promising option to reduce the COD and other element concentrations from dye industry wastewater and improve the water quality. Reducing COD and other water quality parameters through biochar will surely limit the hazardous impacts of wastewater on the surrounding environment.

Several simple, fast and practical protocols have been developed to synthesize internal or terminal propargylamines and chalcones viaA3-coupling reaction of aldehydes, amines, and alkynes catalyzed by an easily available catalyst Ag2CO3under solvent-free condition. The reaction proceeded smoothly to deliver various products in good-to-excellent yields with good functional group tolerance. Gram-scale preparation, bioactive molecule synthesis and asymmetric substrates have been demonstrated. Furthermore, plausible mechanisms for the synthesis of different products have been proposed.

Groundwater contamination by halogenated organic compounds, especially fluorinated ones, threatens freshwater sources globally. Sulfidized nanoscale zero-valent iron (SNZVI), which is demonstrably effective for dechlorination of groundwater contaminants, has not been well explored for defluorination. Here, we show that SNZVI nanoparticles synthesized via a modified post-sulfidation method provide rapid dechlorination (∼1100 μmol m–2day–1) and relatively fast defluorination (∼6 μmol m–2day–1) of a halogenated emerging contaminant (florfenicol) under ambient conditions, the fastest rates that have ever been reported for Fe0-based technologies. Batch reactivity experiments, material characterizations, and theoretical calculations indicate that coating S onto the metallic Fe surface provides a highly chemically reactive surface and changes the primary dechlorination pathway from atomic H for nanoscale zero-valent iron (NZVI) to electron transfer for SNZVI. S and Fe sites are responsible for the direct electron transfer and atomic H-mediated reaction, respectively, and β-elimination is the primary defluorination pathway. Notably, the Cl atoms in florfenicol make the surface more chemically reactive for defluorination, either by increasing florfenicol adsorption or by electronic effects. The defluorination rate by SNZVI is ∼132–222 times higher with chlorine attached compared to the absence of chlorine in the molecule. These mechanistic insights could lead to new SNZVI materials for in situ groundwater remediation of fluorinated contaminants.

The liquid-phase reduction method with NaBH4as the reductant is the most widely used method for sulfidized nanoscale zero-valent iron (SNZVI) synthesis. However, it is unclear how the reductant amount (e.g., NaBH4/Fe ratio) affects the physicochemical properties (i.e.Fe0and S content, surface S speciation, and lattice constant of the Fe BCC structure) and reactivity of SNZVI. Herein, we synthesized SNZVI with different NaBH4/Fe ratios to assess how the NaBH4/Fe ratio affects their properties, and how these properties correlated to the reactivity and selectivity. The S/Fe molar ratio in the particles of SNZVI decreased from 0.15 to 0.02 when the NaBH4/Fe ratio increased from 1.5 to 5, respectively; meanwhile, the yield of SNZVI increased from 20% to 97%. The Fe0content and the surface S2−/S22−molar ratio ([S2−/S22−]surface) increased with the increase of the NaBH4/Fe ratio, which enhanced the electron transfer of SNZVI. The trichloroethylene reactivity increased ∼8.5-fold when the [S2−/S22−]surfaceof SNZVI increased from 0.85 to 1.62, while the selectivity decreased from 82.8% to 64.4% accordingly, indicating that [S2−/S22−]surfacecould be an indicator for predicting the reactivity and selectivity of SNZVI. These results indicate that the NaBH4/Fe ratio is a possible reason for the lab-to-lab variability of SNZVI reactivity. A higher NaBH4/Fe ratio was favorable for the TCE dechlorination reaction while a lower NaBH4/Fe ratio could enhance the electron selectivity.

The safety issue caused by thermal runaway poses a huge threat toward the lifespan and application of high-density electrochemical energy storage devices, especially in the field of micro-energy, such as microsupercapacitors (MSCs). The heat accumulation is difficult to be eliminated, considering the narrow space inside integrated electronic devices attached to the MSC group. Active thermal management is of paramount importance to ensure the normal operation of electronic devices. However, existing one-time thermal protection strategies cannot fully meet current requirements. Herein, we report a promising thermoreversible temperature-responsive electrolyte system, which can shut down the current flow before thermal runaway occurs, thanks to the sol–gel transition of Pluronic [poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide)]-based graft copolymer solution. As the temperature rises to 80 °C, the self-protective electrolyte will change from the sol state to gel state. Meanwhile, the internal resistance increases and ionic conductivity decreases gradually as a result of the gelation of the sol electrolyte. The capacity of the energy storage device using the self-protective electrolyte is reduced by about 95%, and the ionic conductivity remains at only 1% at 80 °C compared with the initial value at room temperature, and it can be restored after cooling down. During 20 heating/cooling cycles, the electrochemical performance is substantially stable, demonstrating a potential approach to achieve repeatability and self-protection for micro-energy storage devices according to temperature changes. In addition, we integrated the as-prepared self-protective electrolyte into MSCs via three-dimensional printing technology to design an all-printed transferable micro-energy storage device with the dynamic reversible self-protection behavior, and the thermo-switchable protection mechanism under series and parallel conditions were studied under appropriate temperature window (25–80 °C). The strategy disclosed herein is expected to provide new insights into the new-generation smart MSCs for their wide applications in diverse fields such as microelectronics and wearable devices.

Electrocatalytic hydrodechlorination (ECH) has been proposed as a potential technology for the effective degradation of organochlorine contaminants. In this study, a nanoscale Pd/TiC catalyst with low resistance was dip-coated onto Ti, aiming to fabricate a stable Pd/TiC/Ti electrode with enhanced ECH reactivity for efficient dechlorination. Electrochemical techniques indicated that the Pd/TiC/Ti electrode had a larger electrochemically active surface area and more rapid interfacial charge transfer than the conventional Pd/C/Ti electrode. In a batch experiment, the dechlorination rate for ECH of 2,4-dichlorobenzoic acid (2,4-DCBA, a model pollutant) by Pd/TiC/Ti was 1.3–14.5 times higher than those by Pd/C/Ti, Pd/MWCNTs/Ti, and Pd/MoS2/Ti, respectively. Scavenger experiments, ESR spin-trapping spectroscopy, and cyclic voltammetry clarified the intensified atomic H* generation by Pd/TiC/Ti. DFT calculations revealed that Pd/TiC/Ti had stronger binding ability with atomic H* (Eads: −2.89 eV vs.−2.44 eV) and 2,4-DCBA (Eads: −3.62 eV vs.−2.15 eV), respectively, when compared with Pd/C/Ti. As a result, enhanced generation of atomic H*, together with strengthened adsorption of atomic H* and 2,4-DCBA, would contribute to a faster ECH reaction. The Pd/TiC/Ti electrode retained its reactivity after 10 successive batch experiments (80 h), and showed high tolerance to the constituents in actual water matrices including lake water and river water. This study proposed a promising ECH electrode for the treatment of chlorinated organics in water matrices.

The recent development about using DESs as green solvents in transition metal catalyzed organic reactions was highlighted, and Au, Metal impregnated on magnetite, Pd, Ru catalyzed organic reactions proceeded smoothly in DESs and gave corresponding products in reasonable yields. And in some cases, the catalytic systems could be recycled up to several times.

Resilience is the ability of a system to withstand and stay operational in the face of an unexpected disturbance or unpredicted changes. Recent studies on air transport system resilience focus on topology characteristics after the disturbance and measure the robustness of the network with respect to connectivity. The dynamic processes occurring at the node and link levels are often ignored. Here we analyze airport network resilience by considering both structural and dynamical aspects. We develop a simulation model to study the operational performance of the air transport system when airports operate at degraded capacity rather than completely shutting down. Our analyses show that the system deteriorates soon after disruptive events occur but returns to an acceptable level after a period of time. Static resilience of the airport network is captured by a phase transition in which a small change to airport capacity will result in a sharp change in system punctuality. After the phase transition point, decreasing airport capacity has little impact on system performance. Critical airports which have significant influence on the performance of whole system are identified, and we find that some of these cannot be detected based on the analysis of network structural indicators alone. Our work shows that air transport system’s resilience can be well understood by combining network science and operational dynamics.

Per- and poly fluoroalkyl substances (PFASs) are often encountered with nonaqueous phase liquid (NAPL) in the groundwater at fire-fighting and military training sites. However, it is unclear how PFASs affect the dechlorination performance of sulfidized nanoscale zerovalent iron (S-nFe0), which is an emerging promising NAPL remediation agent. Here, S-nFe0synthesized with controllable S speciation (FeS or FeS2) were characterized to assess their interactions with PFASs and their dechlorination performance for trichloroethylene NAPL (TCE-NAPL). Surface-adsorbed PFASs blocked materials’ reactive sites and inhibited aqueous TCE dechlorination. In contrast, PFASs-adsorbed particles with improved hydrophobicity tended to enrich at the NAPL–water interface, and the reactive sites were re-exposed after the PFASs accumulation into the NAPL phase to accelerate dechlorination. This PFASs-induced phenomenon allowed the materials to present a higher reactivity (up to 1.8-fold) with a high electron efficiency (up to 99%) for TCE-NAPL dechlorination. Moreover, nFe0-FeS2with a higher hydrophobicity was more readily enriched at the NAPL–water interface and more reactive and selective than nFe0-FeS, regardless of coexisting PFASs. These results unveil that a small amount of yet previously overlooked coexisting PFASs can favor selective reductions of TCE-NAPL by S-nFe0, highlighting the importance of materials hydrophobicity and transportation induced by S and PFASs for NAPL remediation.

The variation in the transference number of H+(aq) is investigated for different HCl solution concentrations. The method for scribing graduations on electromigration tubes is modified to decrease the error in experimental measurements, and metallic copper is used as the anode to reduce the toxicity and environmental impact of the reagents. For very dilute HCl solutions, the correlation between the transference number and HCl concentration is theoretically described using equations derived from the Debye–Hückel–Onsager equation for ionic molar conductivity, and Longsworth’s method is applied to extrapolate the limiting transference number from the raw data. The modified apparatus improves the measurement accuracy, and the relevant calculations are applicable to the laboratory curriculum of senior undergraduate physical chemistry. By careful observation, rigorous analysis and comprehensive data treatment, the students are led to use the knowledge in textbooks to do some creative researches.

Ursodeoxycholic acid (UDCA) was synthesized from commercially available phytosterol-derived bisnoralcohol with an overall yield of 57% by a six-step process. The absolute configuration of the 3,5,7-stereogenic centers in UDCA was determined using Pd-catalyzed and hydroxysteroid dehydrogenase (HSDH)-catalyzed hydrogenation conducted under normal temperature and atmospheric pressure conditions. To investigate the stereoselectivity and regioselectivity of the catalyst and assess the final purity of the product, all potential impurities were synthesized and analyzed using HPLC with charged aerosol detection (CAD). The developed process demonstrated cost-effectiveness and suitability for large-scale production of UDCA with an ICH-grade quality. Our Pd-catalyzed and HSDH-catalyzed hydrogenation techniques could also be applied in the synthesis of alphaxalone and brexanolone.

With the increasing of the installed capacity of wind power, the condition monitoring and maintains technique is becoming more important. Wind Turbines (WT) gearbox is one of the key wind power components as it plays the role of power transmission and speed regulation. Towards this, a number of scholars have pay attention to the fault diagnosis of WT gearbox. The efficiency of Machine Learning (ML) algorithms is highly correlated with signal type, data quality, and extracted features employed. The implementation of ML techniques has proven to be advantageous in simplifying the comprehension prerequisites for fault diagnosis technology concerning fault mechanisms. More and more current studies predominantly concentrate on the utilization and fine-tuning of ML algorithms, while providing limited insights into the features of the acquired data. Therefore, it is necessary to review the research in recent years from the perspective of the combination of feature extraction and ML algorithms, and provide a detailed direction for future WT gearbox fault diagnosis technology research. In this paper, data processing algorithms and typical fault diagnosis methods based on ML methods for WT gearbox are reviewed. For the using of ML method in WT gearbox fault diagnosis, the data prepared for training is very important. The paper firstly reviewed the data analysing method which will support the ML method. The data analysing methods include data acquisition, data preprocessing and feature extraction method. Feature extraction plays a pivotal role in the realm of gearbox fault diagnosis, as it serves as the essence of effective detection. This review will primarily focus on exploring methods that enable the utilization of efficient features in combination with ML techniques to achieve accurate gearbox fault diagnosis. Then typical ML method for WT gearbox fault diagnosis are carefully reviewed. Moreover, some prospects for future research directions are discussed in the end.

Design and fabrication of MXene-based soft actuators with angle-independent structural color.The nanostructured MXene can not only facilitate the formation of short-range ordered 3D amorphous photonic crystals, but also help significantly improve structural color saturation.The soft actuators exhibit brilliant angle-independent structural color, ultrafast actuation and recovery speeds in response to vapor.

Exposing nanoscale zerovalent iron (NZVI) to dissolved sulfide species improves its performance as a remediation agent. However, the impacts of sulfur dose and sulfidation time on morphology, sulfur content, reactivity, and selectivity of the resulting sulfidized NZVI (SNZVI) have not been systematically evaluated. We synthesized SNZVI using different sulfur doses and sulfidation times and measured their properties. The measured S/Fe molar ratio in the particles ([S/Fe]particle) was 10–500 times lower than [S/Fe]dosedbut was predictable based on [S/Fe]dosed× tsulfidation. The low sulfur content (0.02–0.65 mol % S/Fe) inhibited the reaction of SNZVI with water (up to 13-fold) and increased its reactivity with trichloroethene (TCE) (up to 14-fold) and its electron efficiency (up to 20-fold). A higher [S/Fe]particle(0.86–1.13 mol % S/Fe) led to complex particle structures and lowered the resistance to electron transfer but did not improve the benefits realized at the lower S/Fe ratios. Adding small amounts of sulfur into NZVI led to more accumulation of acetylene, especially for low Fe/TCE conditions, suggesting that sulfur lowers the rate of hydrogenation of acetylene to ethene. These results show that [S/Fe]dosed× tsulfidationcan be used to predict the measured S content in the particles and that affects reactivity, longevity, and electron selectivity, for post-SNZVI.

Smartphone thermal cameras can be used to observe heat transfer or thermal patterns in crystallization, evaporation, mixing of liquids, and chemical reactions. The experiments described in this paper demonstrate that IR imaging can provide students with rich learning and exploring opportunities that would otherwise be infeasible or too time-consuming. The precision and sensitivity of smartphone thermal cameras are sufficient for use in chemistry education. A smartphone thermal imaging accessory is worth introducing into the teaching laboratory.

Thermal runaway has always been a significant safety issue that high-performance electronic devices urgently need to solve. These existing strategies are limited by the lack of reversibility and low conductivity. Here, we propose a novel thermoreversible self-protection microsupercapacitor (TS-MSC) based on a thermoresponsive polymer electrolyte to prevent thermal runaway. When heating above the low critical solution temperature (LCST), a gelation process occurs in the smart electrolyte and effectively inhibits the migration of ions, leading to a decreased specific capacitance and an increased internal resistance of the MSC. However, the electrolyte transforms to a solution state at room temperature in which ions can freely migrate. Benefiting by sol–gel transition of the smart electrolyte, the TS-MSCs can exhibit different electrochemical performances at elevated temperatures, demonstrating an active method of achieving thermoreversible and dynamic self-protection. In addition, 3D printing technology and substrate versatility provide an attractive method in the design of integrated micropower devices. Therefore, such functional TS-MSCs offer a promising strategy to solve the safety issues of the nowadays portable microelectronic devices.

The recent development in transition metal catalyzed cross coupling of nitroarenes was highlighted. And nitroarenes were efficient electrophilic coupling partners for constructing C–O, C–S, CC and C–N bonds.

Next-generation wearable electronics are expected to endure significant deformations and mechanical damage. Therefore, self-healing stretchable electrolytes with high ionic conductivity and robust mechanical strength, which have high tolerance of deformations and spontaneously recover electrochemical properties after external damage, are necessary conditions for the realization of flexible supercapacitors. Here, a new type of zwitterionic supramolecular hydrogel cross-linked through rationally designed ionic associations and hydrogen bonds is reported (PAD/H2SO4). The resultant supramolecular network realizes a high ionic conductivity of 57 mS cm–1and unprecedented mechanical properties such as a high toughness of 35 000 J m–2, a notch-insensitive of up to 2200% strain, and efficient instantaneous self-healing within 5 min. Acting as an electrolyte, a novel flexible supercapacitor design strategy is proposed by integrating capacitive materials directly onto the PAD/H2SO4hydrogel to achieve exceptional electrochemical performance, which can be repeatable for at least 50 cutting/healing cycles. The facile and versatile strategy for the construction of the integrated all-gel-state supercapacitors with self-healing stretchable electrolytes will provide new directions for future long-life flexible devices.

Aims: Secretomics will lead to an increase in understanding of how cells combine the concerted action of secreted protein networks with their internal and external environments. Methods: Shotgun proteomics were used to analyze Synechocystis sp. PCC 6803 secreted proteins and results showed the identification of unique proteins, 13 in normal medium and 7 in phosphate-depleted BG-11 medium, respectively. Results: Six proteins were secreted under both normal and phosphate-depleted conditions (slr0513, slr1667, sll0654, sll1694, sll1578, sll1009), but only one secreted protein (Sll1694) was commonly detected by shotgun proteomics in the present study and previous gel-based studies. Both the number of secreted proteins and their classifications decreased in phosphate-depleted conditions. The peptide count of hypothetical protein codified by slr1667 decreased significantly under phosphate-depleted conditions, whereas alkaline phosphatase protein codified by sll0654 increases significantly under phosphate- depleted conditions. Results of quantitative real-time PCR showed that the transcript level of alkaline phosphatases (sll0654) was higher in phosphate-depleted BG-11 medium than in normal medium, and the transcript level of proteins related to twitching motility decreased significantly. Conclusion: This comprehensive data set provides novel insights into the composition and function of the cyanobacterium secretome and improves understanding of the biological processes at work between cyanobacterium and its environment.

History: The freshwater cyanobacteria genus Microcystis includes some of the dominating cyanobacteria species in algae blooms and is distributed worldwide. Method: We collected three types of Microcystis, M. aeruginosa (FACHB 912), M. flos-aquae (FACHB 1028), and M. ichthyoblabe (FACHB 1294), from Lake Taihu in China to analyze their secretome in culture medium using shotgun proteomics. Observations: We identified 51, 92, and 44 unique proteins in M. aeruginosa, M. flos-aquae, and M. ichthyoblabe, respectively. The largest fraction of proteins had an unknown and hypothetical function. Results: Only five (MAE27990, MAE06090, MAE59990, MAE47530, MAE36530) of these proteins were expressed in all three Microcystis species. Gas vesicle structural proteins were present in the secretome of both M. aeruginosa and M. flos-aquae, but not in that of M. ichthyoblabe. Conclusion: This comprehensive dataset provides a novel insight into the composition and function of cyanobacterium secretome. We also analyzed proteins found in our proteomic experiment that were related to Microcystis buoyancy motility.

A transition-metal-free protocol capable of synthesizing diarylated aniline derivatives is reported. This method could be further employed to prepare aryl alkyl ethers. A wide range of thioethers, anilines, as well as alcohols were tolerated thanks to the mild reaction conditions. The strength of our method was demonstrated by performing a gram-scale reaction (20 mmol) followed by conversion of the nitrile group into synthetically useful aldehyde, ketone, and carboxylic acid.

Uniform dispersion of two-dimensional (2D) graphene materials in polymer matrices remains challenging. In this work, a novel layer-by-layer assembly strategy was developed to prepare a sophisticated nanostructure with highly dispersed 2D graphene oxide in a three-dimensional matrix consisting of one-dimensional bacterial cellulose (BC) nanofibers. This method is a breakthrough, with respect to the conventional static culture method for BC that involves multiple in situ layer-by-layer assembly steps at the interface between previously grown BC and the culture medium. In the as-prepared BC/GO nanocomposites, the GO nanosheets are mechanically bundled and chemically bonded with BC nanofibers via hydrogen bonding, forming an intriguing nanostructure. The sophisticated nanostructure of the BC/GO leads to greatly enhanced mechanical properties compared to those of bare BC. This strategy is versatile, facile, scalable, and can be promising for the development of high-performance BC-based nanocomposite hydrogels.

A major stumbling block in large-scale adoption of high-energy-density electrochemical devices has been safety issues. Methods to control thermal runaway are limited by providing a one-time thermal protection. Herein, we developed a simple and reversible thermoresponsive electrolyte system that is efficient to shutdown the current flow according to temperature changes. The thermal management is ascribed to the thermally activated sol–gel transition of methyl cellulose solution, associated with the concentration of ions that can move between isolated chains freely or be restricted by entangled molecular chains. We studied the effect of cellulose concentration, substituent types, and operating temperature on the electrochemical performance, demonstrating an obvious capacity loss up to 90% approximately of its initial value. Moreover, this is a cost-effective approach that has the potential for use in practical electrochemical storage devices.

Hollow silica spheres possessing excellent mechanical properties were successfully prepared through a layer-by-layer process using uniform polystyrene (PS) latex fabricated by dispersion polymerization as template. The formation of hollow SiO2micro-spheres, structures and properties were observed in detail by zeta potential, SEM, TEM, FTIR, TGA and nitrogen sorption porosimetry. The results indicated that the hollow spheres were uniform with particle diameter of 1.6 μm and shell thickness of 150 nm. The surface area was 511 m2/g and the pore diameter was 8.36 nm. A new stationary phase for HPLC was obtained by using C18-derivatized hollow SiO2micro-spheres as packing materials and the chromatographic properties were evaluated for the separation of some regular small molecules. The packed column showed low column pressure, high values of efficiency (up to about 43 000 plates/m) and appropriate asymmetry factors.

Highly ordered three-dimensional (3D) polypyrrole (PPy) coated cobalt oxide (Co3O4) nanoneedle arrays (NAs) anchored on Cu foams (Co3O4NAs@PPy) are fabricated for electrochemical sensors to detect trace lead ions (Pb2+). The 3D hybrid Co3O4NAs@PPy is synthesized viaa hydrothermal method followed by a chemical vapor phase polymerization process. Free-standing Co3O4NAs@PPy can be directly utilized as a 3D electrochemical working electrode without being decorated onto a working electrode like Au and glassy carbon electrodes. In the mean time, the simultaneous incorporation of PPy, Co3O4and Cu foams creates a platform with significantly improved electrochemical properties and excellent sensitivity for a large specific surface area, eminent adsorption capacity and high conductivity. Square wave anodic stripping voltammetry (SWASV) is carried out to observe the electrochemical behavior of the Co3O4NAs@PPy electrode. Under the optimum conditions, a linear range between the currents and the concentrations of Pb2+from 0.024 to 0.48 μM with a high sensitivity of 85.5 μA μM−1was obtained. The limit of detection can reach 0.58 nM. The results confirmed that the modified electrode is a good candidate for Pb2+detection sensors with excellent reproducibility, stability and lower detection limit. In addition, the developed method was successfully applied to determine Pb2+in real water samples with satisfactory results.

A practical synthetic method for 4-thiocyanato-1H-pyrazoles through the electrochemical cascade reaction of hydrazines, 1,3-diones and NH4SCN under metal-, chemical oxidant- and external electrolyte-free conditions was established. Importantly, both a gram-scale synthesis of 4-thiocyanato-1H-pyrazoles and five one-pot sequential transformations starting from hydrazine were successfully accomplished.

Single-atom catalysts (SACs) have emerged as promising materials for efficient environmental remediation due to their unique properties and high catalytic efficiency. The incorporation of non-metal p-block elements into the SACs framework imparts distinct electronic and chemical properties, holding promise toward highly selective catalysis. This review provides fundamentals and strategies for tailoring the microenvironments of SACs with non-metal p-block elements toward selective environmental processes. Significantly, a bridge between the doping elements and catalytic selectivity is built by exploring the impacts of their characteristics on the geometric and electronic structures of SACs, including bulk physicochemical properties, local electronic effects, and adsorption configuration and intensity of intermediates. In-depth explorations of how these elements’ incorporation affects the performance of SACs are presented for the selective generation of H2O2via oxygen reduction, selective generation of radicals via persulfate (PS)-based advanced oxidation processes, and selective reduction of CO2. Challenges and opportunities associated with tailoring the microenvironments of SACs are finally discussed. This review will help guide the rational design of SACs with superior performance for selective environmental processes to better deal with environmental concerns.

Electrocatalytic hydrodechlorination (ECH) based on Pd-modified Ni foam electrodes offers a sustainable approach for decontaminating halogenated chlorinated organics, but the synthesis of Pd/Ni foam is always poorly controlled. In this work, with clofibric acid (emerging as a typical pharmaceutical) as a probe contaminant, we show that the ECH performance of Pd/Ni foam is highly dependent on the impregnation time during its preparation. During preparation, the dissolved Ni2+can combine with aqueous OH–to form in situ Ni(OH)2coatings on Pd/Ni foam. By prolonging the impregnation time, continuous deposition of Ni(OH)2gradually increases the anti-corrosive property and the electrochemically active surface area of the electrode. However, such covered Ni(OH)2coatings promote the interfacial charge transfer resistance and hinder the atomic H* adsorption by Pd, which is detrimental to ECH. This work provides a novel strategy for the synthesis of Pd/Ni foam electrodes with an enhanced ECH property for electroreductive remediation of chlorinated pharmaceutical compounds.

A highly selective hydrogenation of 3-keto in steroids to 3-hydroxyl steroids catalyzed by hydroxysteroid dehydrogenases (HSDHs) was demonstrated. The Ct3α-HSDH-catalyzed hydrogenation generated 3α-hydroxyl steroids as the main enantiopure isomers in high yields, while the Ss3β-HSDH catalytic system afforded 3β-hydroxyl steroids in excellent yields. In both catalytic systems, the hydrogenation proceeded regioselectively at 3-keto with 7-, 11-, 17-, and 20-keto almost unreacted, and chemoselectively with the C═C bond and ester group unattacked. Our HSDH-promoted hydrogenation showed advantages like high regio-, chemo-, and enantioselectivity, good yields, mild conditions, a wide substrate scope, and being suitable for gram-scale synthesis. Notably, bioactive molecules like dehydroepiandrosterone, brienolone, and alfaxalone were obtained facilely in high yields via our hydrogenation approach.

Calcination is considered to increase the hardness of composite material and prevent its breakage for the effective applications in environmental remediation. In this study, magnetic biochar amended with silicon dioxide was calcined at high temperature under nitrogen environment and characterized using various techniques. X-ray diffraction (XRD) analysis revealed elimination of Fe3O4peaks under nitrogen calcination and formation of Fe3Si and iron as major constituents of magnetic biochar-SiO2composite, which demonstrated its superparamagnetic behavior (>80 A2·kg−1) comparable to magnetic biochar. Thermogravimetric analysis (TGA) revealed that both calcined samples generated higher residual mass (>96 %) and demonstrated better thermal stability. The presence of various bands in Fourier transform infrared spectroscopy (FT-IR) was more obvious and the elimination of H–O–H bonding was observed at high temperature calcination. In addition, scanning electron microscopy (SEM) images revealed certain morphological variation among the samples and the presence of more prominent internal and external pores, which then judged the surface area and pore volume of samples. Findings from this study suggests that the selective calcination process could cause useful changes in the material composites and can be effectively employed in environmental remediation measures.

Two-dimensional (2D) ultrathin TiO2nanosheets doped with quantum Cu(II) nanodots (QCNs) were synthesized through an in situ photodeposition for reforming glycerol. The optimized QCNs dopant exhibited favorable H2evolution rate of up to 25-fold compared with bare TiO2. The prepared QCNs permeated into the homogeneous {001} facets resulting in discontinuous quantum nanodot doping, which was confirmed by energy-dispersive X-ray (EDX) spectroscopy. Analysis suggests that the suppressed recombination rate of the photoinduced electron–hole pair and the prolonged lifetime are benefits for enhancing photocatalytic performance. A photoinduced interfacial charge-transfer (IFCT) effect introduced by doping QCN was certified by electron spin resonance (ESR) spectroscopy. This offered more photoinduced electrons and holes for redox reaction including H2production and CO2and CO yields. Electrochemical characterizations were carried out to reveal that QCN could improve the photocurrent density and shift the conduction band (CB) potentials to negative direction. With all the characterizations conducted in this paper, a probable mechanism was proposed to represent the multiple charge-transfer pathways. Here, we provide a new modification strategy for designing QCNs/TiO2and explore the mechanism involved in 2D ultrathin nanostructures doped with variable-valence metal quantum nanodots. The multiple charge-transfer pathways system applied to photocatalytic H2production and environmental waste disposition in a facile and green manner may be further employed to synthesize other variable-valence metal doping systems.

2,4-dichlorophenol was effectively removed from water using magnetic Pd/Fe nanoparticles supported on multiwalled carbon nanotubes (MWCNTs). The adsorption kinetics, isotherms, and energy for 2,4-dichlorophenol and its partially (4-chlorophenol, 2-chlorophenol) and completely (phenol) dechlorinated products are presented and discussed. The adsorption capacity was 2,4-dichlorophenol > 4-chlorophenol > 2-chlorophenol > phenol for MWCNTs. MWCNTs-Fe3O4–Pd/Fe nanohybrids provided rapid adsorption, gradual dechlorination, and final desorption of phenol, which is attractive as a remediation technology. Over 82.7% of the phenol was desorbed and released to the aqueous phase after 72 h due to its low adsorption capacity, leaving the majority of active sites available on the surface of MWCNTs-Fe3O4–Pd/Fe. The nanohybrids maintained high activity in five consecutive in situ experiments, and they were retrievable using magnetic separation. MWCNTs-Fe3O4–Pd/Fe nanohybrids outperform unsupported Pd/Fe nanoparticles, which were difficult to retrieve, and were easily passivated and aggregated.

Bacterial adhesion and biofilm formation are the primary causes of implant-associated infection, which is difficult to eliminate and may induce failure in dental implants. Chimeric peptides with both binding and antimicrobial motifs may provide a promising alternative to inhibit biofilm formation on titanium surfaces. In this study, chimeric peptides were designed by connecting an antimicrobial motif (JH8194: KRLFRRWQWRMKKY) with a binding motif (minTBP-1: RKLPDA) directly or via flexible/rigid linkers to modify Ti surfaces. We evaluated the binding behavior of peptides using quartz crystal microbalance (QCM) and atomic force microscopy (AFM) techniques and investigated the effect of the modification of titanium surfaces with these peptides on the bioactivity of Streptococcus gordonii(S. gordonii) and Streptococcus sanguis(S. sanguis). Compared with the flexible linker (GGGGS), the rigid linker (PAPAP) significantly increased the adsorption of the chimeric peptide on titanium surfaces (p< 0.05). Concentration-dependent adsorption is consistent with a single Langmuir model, whereas time-dependent adsorption is in line with a two-domain Langmuir model. Additionally, the chimeric peptide with the rigid linker exhibited more effective antimicrobial ability than the peptide with the flexible linker. This finding was ascribed to the ability of the rigid linker to separate functional domains and reduce their interference to the maximum extent. Consequently, the performance of chimeric peptides with specific titanium-binding motifs and antimicrobial motifs against bacteria can be optimized by the proper selection of linkers. This rational design of chimeric peptides provides a promising alternative to inhibit the formation of biofilms on titanium surfaces with the potential to prevent peri-implantitis and peri-implant mucositis.

Silicon (Si) has been widely investigated as a candidate for lithium-ion batteries (LIBs) due to its extremely high specific capacity. The binders play a key role in fabricating high-performance Si electrodes which usually suffer from the huge volume expansion associated with the alloying and dealloying processes. Here we develop a facile route to prepare a three-dimensional (3D) conductive interpenetrated gel network as a novel binder for high-performance Si anodes through chemically cross-linking of acrylic acid monomer followed by the in situ polymerization of aniline. The excellent electrical conductivity, strong mechanical adhesion and high electrolyte uptake render the conductive gel network a potential binder for high-performance Si anodes. The resultant Si anodes exhibit excellent cycling stability, high Coulombic efficiency and superior rate capability, revealing better electrochemical properties compared to the Si anodes with conventional binders. The 3D conductive gel binder could not only accommodate the volume expansion and maintain electric connectivity, but also assist in the formation of stable solid electrolyte interphase (SEI) films. Such a strategy sheds light on the design of polymer binders in LIBs, especially for high-capacity electrode materials with huge volume changes during long-term cycling.

Various well-designed nanostructures have been proposed to optimize the electrode systems of lithium-ion batteries for problems like Li+diffusion, electron transport, and large volume changes so as to fulfill effective capacity utilization and increase electrode stability. Here, a novel three-dimensional (3D) hybrid Sn–Ni@PEO nanotube array is synthesized as a high performance anode for a lithium-ion battery through a simple one-step electrodeposition for the first time. Superior to the traditional stepwise synthesis processes of heterostructured nanomaterials, this one-step method is more suitable for practical applications. The electrode morphology is well preserved after repeated Li+insertion and extraction, indicating that the positive synergistic effect of the alloy nanotube array and 3D ultrathin PEO coating could authentically optimize the current volume-expansion electrode system. The electrochemistry results further confirm that the superiority of the Sn–Ni@PEO nanotube array electrode could largely boost durable high reversible capacities and superior rate performances compared to a Sn–Ni nanowire array. This proposed ternary hybrid structure is proven to be an ideal candidate for the development of high performance anodes for lithium-ion batteries.

Lymphovascular invasion is considered to be a high-risk pathological feature after radical resection of gastric cancer, but the relationship between lymphovascular invasion and the prognosis of stage I gastric cancer is still controversial. Therefore, we used meta-analysis to systematically evaluate the relationship between lymphovascular invasion and the prognosis of stage I gastric cancer. Up to September 2, 2021, the databases of PubMed, EMBASE, Cochrane Library, CNKI, and Wanfang were searched. According to the inclusion and exclusion criteria, 2 researchers independently completed the screening of literature, extraction of data, and quality evaluation. Meta-analysis was performed using RevMan 5.4 software merged with HRand 95%CI. A total of 7508 patients with stage I gastric cancer were included in 9 studies, and the positive rate of lymphovascular invasion was 17%. Lymphovascular invasion was significantly associated with shorter overall survival (OS) (univariate: HR= 4.05, 95%CI: 1.91–8.58; multivariate: HR= 2.10, 95%CI: 1.37–3.22) and relapse-free survival (RFS) (univariate: HR= 4.79, 95%CI: 2.30–9.99; multiple: HR= 2.17, 95%CI: 1.56–3.00). This study indicates that lymphovascular invasion is an independent risk factor affecting the prognosis of patients with stage I gastric cancer, and can be used as a reference index for postoperative adjuvant therapy.

In this study, surfactant-modified layered double hydroxides (LDHs) were prepared via a hydrothermal method using sodium dodecyl sulfate (SDS). The synthesized sorbent (DS-LDH) was utilized for the removal of Sb(V) from aqueous solutions. The results demonstrated that DS4-LDH with a SDS/(Mg2++Al3+) molar ratio of 0.35 exhibited excellent Sb(V) sorption ability (136 mg g−1), which was 11 times that of pure LDH (12 mg g−1), for an initial Sb(V) concentration of 40 mg L−1. Acidic and alkalescent aqueous solutions and ionic strength hardly affected Sb(V) sorption by DS4-LDH, whereas strong alkalinity inhibited Sb(V) sorption. Under neutral conditions, coexisting anions, including sulfate and phosphate, exhibited a significant influence on Sb(V) removal, whereas chloride, acetate, and carbonate had negligible effects. Ion exchange and the formation of brandholzite-like structures primarily contributed to the Sb(V) sorption by DS4-LDH. The intercalation of dodecyl sulfate ions in LDH increased the interlayer spacing, which enhanced anion exchange between the original interlayer ions of LDH and Sb(OH)6-, and facilitated contact between the interlayer functional sites and Sb(OH)6-, leading to an improved removal of Sb(V). This study proposes a new concept for the development of high-performance LDH sorbents modified by organic surfactants, which could be promising remediating substances for the efficient removal of Sb(V).

To improve the separation rate of photogenerated electrons and holes, a SnO2/rutile TiO2(R-TiO2)/anatase TiO2(A-TiO2) photocatalyst modified by Pt nanoparticles with three pairs of heterojunctions was fabricated by a facile hydrothermal method. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) clearly illustrated the structure of the three pairs of heterojunctions connected to each other. Heteronanostructure photocatalysts with increased specific surface area could offer more active sites when contacting pollutants, resulting in improved photocatalytic activity. The red shift in UV–vis diffuse reflectance spectra (DRS) indicated the utilization of visible-light. Photoluminescence (PL) and photoelectrochemical (PEC) measurements suggested the enhancement of electron and hole separation, in accordance with the results obtained for the photocatalytic oxidation of decomposing toluene over 4 h. A catalyst containing 1 wt % Pt/10 at. % SnO2/R-TiO2/A-TiO2exhibited the best photocatalytic mineralization rates of toluene: 40.9% and 72.3% under visible-light and UV-light irradiation, respectively. A proposed mechanism was elaborated to reveal the effective photocatalytic progress of charge transfer along multiple pathways along the three pairs of heterojunctions doped with Pt.

AbstractThe potential of Cr(VI) reduction by Escherichia coliin the presence of soluble Fe(III) was investigated to explore the chemo-biologically mediated reduction process under anaerobic condition. The reduction efficiency of Cr(VI) reached 95% within 24 h. The influences of experimental parameters, including initial pH, temperature, Fe(III) dosage, carbon source, and chelating agent, were also investigated. The highest efficiency of reduction was observed when pH was 5.8 and temperature was 32°C. Amendments of culture medium with Fe(III) and citric-3Na enhanced Cr(VI) reduction, while the addition of EDTA-2Na inhibited the process. Analysis showed that soluble Fe(III) enhanced the reduction process by shuttling electrons from bio-reduced Fe(II) to Cr(VI) in a coupled biotic-abiotic cycle and hence, Cr(VI) was reduced to Cr(III) followed by deposition to sludge.

The potential of Cr(VI) reduction by Escherichia coliin the presence of soluble Fe(III) was investigated to explore the chemo-biologically mediated reduction process under anaerobic condition. The reduction efficiency of Cr(VI) reached 95% within 24 h. The influences of experimental parameters, including initial pH, temperature, Fe(III) dosage, carbon source, and chelating agent, were also investigated. The highest efficiency of reduction was observed when pH was 5.8 and temperature was 32°C. Amendments of culture medium with Fe(III) and citric-3Na enhanced Cr(VI) reduction, while the addition of EDTA-2Na inhibited the process. Analysis showed that soluble Fe(III) enhanced the reduction process by shuttling electrons from bio-reduced Fe(II) to Cr(VI) in a coupled biotic-abiotic cycle and hence, Cr(VI) was reduced to Cr(III) followed by deposition to sludge.

Carbon black supported ultra-high loading silver nanoparticle catalyst (Ag/CB) was prepared by a modified ethylene glycol reduction method, using ethylene glycol as the reducing agent and sodium hydroxide as the pH adjusting agent. The X-ray diffraction, thermogravimetry and scanning electron microscopy characterizations showed that the Ag nanoparticles crystallized with a face-centered cubic structure and were densely stacked on the CB surface without aggregation, despite such a small average size (ca. 10 nm) and an ultra-high loading mass (392 wt.%). The electrochemical evaluation based on cyclic voltammetry, chronoamperometry and polarization tests revealed that the ultra-high loading Ag/CB catalyst possessed a superior electrocatalytic activity for the oxidation of hydrazine, via a diffusion-limited process and a 4-electron transfer pathway. Moreover, the chronoamperometry response on an electrode modified with this ultra-high loading Ag/CB catalyst exhibited a promising application for determination of hydrazine, due to a broad linear calibration ranging from 50 to 800 μM, a high sensitivity of 0.03795 μA/μM and a low detection limit of 3.47 μM.

Strong Lewis acids of air‐stable metallocene bis(perfluorooctanesulfonate)s [M(Cp)2][OSO2C8F17]2⋅nH2O⋅THF (M=Zr (2 a⋅3 H2O⋅THF), M=Ti (2 b⋅2 H2O⋅THF)) were synthesized by the reaction of [M(Cp)2]Cl2(M=Zr (1 a), M=Ti (1 b)) with nBuLi and C8F17SO3H (2 equiv) or with C8F17SO3Ag (2 equiv). The hydrate numbers (n) of these complexes were variable, changing from 0 to 4 depending on conditions. In contrast to well‐known metallocene triflates, these complexes suffered no change in open air for a year. thermogravimetry–differential scanning calorimetry (TG‐DSC) analysis showed that 2 aand 2 bwere thermally stable at 300 and 180 °C, respectively. These complexes exhibited unusually high solubility in polar organic solvents. Conductivity measurement showed that the complexes (2 aand 2 b) were ionic dissociation in CH3CN solution. X‐ray analysis result confirmed 2 a⋅3 H2O⋅THF was a cationic organometallic Lewis acid. UV/Vis spectra showed a significant red shift due to the strong complex formation between 10‐methylacridone and 2 a. Fluorescence spectra showed that the Lewis acidity of 2 afell between those of Sc3+(λem=474 nm) and Fe3+(λem=478 nm). ESR spectra showed the Lewis acidity of 2 a(0.91 eV) was at the same level as that of Sc3+(1.00 eV) and Y3+(0.85 eV), while the Lewis acidity of 2 b(1.06 eV) was larger than that of Sc3+(1.00 eV) and Y3+(0.85 eV). They showed high catalytic ability in carbonyl‐compound transformation reactions, such as the Mannich reaction, the Mukaiyama aldol reaction, allylation of aldehydes, the Friedel–Crafts acylation of alkyl aromatic ethers, and cyclotrimerization of ketones. Moreover, the complexes possessed good reusability. On account of their excellent catalytic efficiency, stability, and reusability, the complexes will find broad catalytic applications in organic synthesis.

In this article, DTC-S, a kind of heavy metal capturing agent, was chosen to evaluate the removal effects of complex copper solutions. The complex copper was 5.0 mg/l. The Cu(II)-NH3was easily removed due to its similarity of free Cu2+in aqueous solution, and the suitable conditions were initial pH 9.0, 20 mg/l DTC-S and one hour's precipitation. The Cu(II)-EDTA and Cu(II)-Cit were more stable due to their ligands. To reach the standard, the optimal dosage of DTC-S was doubled, and the initial pH was adjusted between 9.5-11.5. The removal rate slightly decreased when external metal ions existed in Cu(II)-EDTA solution. Infrared spectra and SEM micrographs showed the DTC-S was a dithiocarbamate compound, whose functional groups could chelate copper ions in copper complexations.

AbstractIn this article, DTC-S, a kind of heavy metal capturing agent, was chosen to evaluate the removal effects of complex copper solutions. The complex copper was 5.0 mg/l. The Cu(II)-NH3was easily removed due to its similarity of free Cu2+in aqueous solution, and the suitable conditions were initial pH 9.0, 20 mg/l DTC-S and one hour’s precipitation. The Cu(II)-EDTA and Cu(II)-Cit were more stable due to their ligands. To reach the standard, the optimal dosage of DTC-S was doubled, and the initial pH was adjusted between 9.5−11.5. The removal rate slightly decreased when external metal ions existed in Cu(II)-EDTA solution. Infrared spectra and SEM micrographs showed the DTC-S was a dithiocarbamate compound, whose functional groups could chelate copper ions in copper complexations.

An airstable cationic organobismuth perfluorooctanesulfonate possessing both acidic and basic characters was synthesized, and showed high catalytic activity, diastereoselectivity, stability, and reusability in the onepot synthesis of Eα,βunsaturated ketones through highly selective crossed condensation of ketones and aldehydes in water.