Co3O4 is a promising heterogeneous catalyst for activating peroxymonosulfate (PMS) to degrade refractory organic wastewater. However, a further improvement in its catalytic performance towards PMS is highly needed for practical applications. For this goal, we prepared sulfur-modified Co3O4/Eu2O3 nanocomposite as the PMS activator using a facile oxalate-pyrolysis approach with thiosulfate as the sulfur source in this study. Methylene blue (MB), a typical cation dye used in diverse applications, was chosen as the degradation model to evaluate the performance of the catalysts. Under the conditions of catalyst dosage of 0.04 g L−1, PMS concentration of 0.6 mmol L−1 and reaction temperature of 25 °C, an MB degradation ratio up to 99.49% was achieved in the sulfur-modified Co3O4/Eu2O3-PMS reaction system within 30 min. Impressively, the reaction rate constant for MB degradation in this system was 0.1704 min−1, which was vastly higher than that in the systems of Co3O4/Eu2O3-PMS and single PMS. In addition, it was confirmed that sulfur was bonded on the surface of Co3O4/Eu2O3 in the form of SO42−. The increased specific surface area and enhanced polarization effect towards PMS caused by the modification of sulfate were regarded as the main reasons for the boosted catalytic performance of Co3O4/Eu2O3. Moreover, it was proven that MB degradation in the sulfur-modified Co3O4/Eu2O3-PMS system was the result of co-action of ˙SO4−, ˙OH, ˙O2− and 1O2 according to the electron paramagnetic resonance (EPR) tests. This work offers a new concept for the design and preparation of non-metal functionalized heterogeneous cobalt-based catalysts for effective PMS activation and rapid removal of recalcitrant pollutants.

Herein, we report the first one-pot K-10 montmorillonite-promoted construction of densely functionalized 4H-chromene skeletons, which are broadly existing structural motifs in natural products and pharmaceutically active molecules, from salicylaldehydes, dimedones and carbon, nitrogen, or sulfur-based bioactive nucleophiles in aqueous medium. Easy recovery and reusability of K-10 montmorillonite without significant reaction erosion, in a short reaction time, with broad substrate scope, and excellent yields, without requiring a toxic organic solvent during the entire process makes this protocol very useful for both industry and academia. Montmorillonite was proven to be the key to furnishing the reactions because the use of other catalysts other than montmorillonite predominantly afforded many side products.

Sodium-ion batteries and supercapacitors look promising candidates as an alternative solution for electrochemical energy storage due to their decent energy density, low cost, good reversibility, and high abundance on the Earth's surface. Sodium-ion batteries exhibit analogous performance to lithium-ion batteries, with the requirements of essential electrolytes and electrode materials. Understanding ionic diffusion in cathode materials is crucial. Here, we study P2-layered Na0.67MnO2 and with 10% Mg-doping, i.e., Na0.67Mn0.9Mg0.1O2, as cathode materials using first-principles calculations and classical molecular dynamics (MD) simulations. We report their ionic diffusion and conduction mechanism using MD simulation methods. We report an enhancement in the transport properties of cathode materials by partial substitution of Mg in Mn octahedral sites, which accelerates the diffusion of Na ions and high-conductivity Na+ ions compared to Na0.67MnO2. Such behavior in an Na-ion battery cathode material focuses on high-availability metals Mn, Mg, and Na. We summarise the results of various computational methods in finding the optimized structure, electronic calculations, cathodic properties, and diffusion properties. Our study will help us understand the Na chemistry involved in developing cathode materials for large-scale applications.

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Solid oxide electrolytic cells (SOECs) are widely used in energy conversion and storage technology. However, the traditional cermet material as the cathode is easily oxidized, which greatly reduces the electrolytic performance and efficiency. In this research work, we produce a range of A-site saturated B-site overdoped La0.7Sr0.3Cr0.5Mn0.5(FeCo)xO3−δ(LSCM(FeCo)x) samples through liquid-phase synthesis. Through the reduction pretreatment of the LSCM(FeCo)x sample, FeCo alloys are separated from the substrate in the form of alloy nanoparticles and anchored to the substrate to construct the metal–oxide interface and increase the active site. Compared to metal nanoparticles, the size effect of alloy nanoparticles can effectively improve the thermal stability and oxidation resistance of materials and enhance their high-temperature durability. Simultaneously, the three-phase interface consisting of the electrode, the electrolyte, and the gas is increased. The coupling of the metal–oxide interface and the three-phase interface enhances the catalytic activity. At 1.6 V and 850 °C, the electrode LSCM(FeCo)0.075 resulted in a Faraday current efficiency close to 100% and a yield of 5.03 ml min−1 cm−2 of CO, about 2.5 times as much as conventional LSCM electrodes. After 100 h of high-temperature testing, the electrochemical performance is stable, which indicates that the construction of the metal–oxide active interfaces and three-phase interfaces could improve the electrocatalytic performance and durability of the material. This research result can provide a reference for the design of efficient and stable catalysts for high-temperature energy and environmental devices.

Herein, we present a novel approach for fabricating porous carbon nanotube–polydimethylsiloxane (CNT–PDMS) sponge electrodes for piezoelectric/piezoresistive sensing. Using a combination of sugar template methods and dip-coating techniques, we synthesize porous CNT–PDMS sponge electrodes via a straightforward manufacturing process. The electrical properties and mechanical strength of the electrodes can be adjusted finely by varying the concentration of the carbon nanotube (CNT) solution and immersing time. Through an analysis of the wetting behavior, compression tests, and electrical durability assessments, the optimal conditions for electrode production are identified. Although no significant changes in the water droplet contact angles are observed based on the CNT coating conditions, the CNT solution concentrations increased and the immersion times prolonged, which are correlated with enhanced mechanical robustness and electrical resilience. Furthermore, the porous CNT–PDMS sponge electrodes exhibit distinct sensitivity to compression displacement owing to variations in their pore structures. Additionally, these electrodes demonstrate consistent and stable piezoelectric/piezoresistive properties across various compression speeds while showing minimal sensitivity to the compression speed. The porous CNT–PDMS sponge electrode fabricated under the 3 wt%-60 min conditions demonstrates significant potential as a highly effective piezoelectric/piezoresistive sensor for human motion detection.

The irradiation of chromone-2-carboxylic esters with a blue LED in the presence of Rose Bengal and triethanolamine (TEOA) is used to obtain 2,2′-bichromanone of methyl, ethyl, n-propyl, iso-propyl, n-butyl, n-pentyl, and n-hexyl chromone-2-carboxylic esters in 52–93% yield and drtrans : cis up to 83 : 17. The key role played by Rose Bengal, TEOA, and blue light was established through numerous control experiments and a plausible mechanism is discussed.

Quick and highly sensitive detection of the SARS-CoV-2 virus can efficiently reduce the possibility of viral spreading. In this study, a differential-phase surface plasmon resonance (SPR) biosensor is constructed to directly detect the SARS-CoV-2 virus. The SARS-CoV-2 spike protein antibodies are applied as bioprobes and functionalized on Au film, forming a sensing surface. A numerical analysis of the phase shifts of the SPR interferogram, termed the index of phase shifts (IoPS), is presented, which does not depend on a reference beam or an s-component beam. The IoPS can sensitively reflect small changes in the refractive index (as low as 3.75 × 10−10 RIU) when NaCl solution is used as an analyte. The limit of detection (LOD) of the proposed SPR biosensor in detecting the SARS-CoV-2 S protein is 1 ag mL−1. In comparison with a SARS-CoV-2 negative control (NC) sample collected from healthy people, which has an IoPS of ΔϕNC = 39°, the SPR biosensor shows a very strong response to the SARS-CoV-2 virus collected from infected people with a phase shift of ΔϕIoPS = 566°. To further improve the detection sensitivity, a sandwich structure is designed by applying SARS-CoV-2 spike protein antibody functionalized gold nanoparticles (anti-S@AuNPs). This reduces the LOD for the detection of the SARS-CoV-2 S protein to 0.1 ag mL−1.

Ti3C2Tx, as some of the typical MXenes, exhibit great potential for application in rechargeable batteries due to its high conductivity, low ionic diffusion resistance, adjustable layer spacing, and surface modifiability. However, several challenges hinder its practical value, including severe self-stacking, low capacity, and unsatisfactory durability, particularly when accommodating large sodium ions. To address these issues, we have designed a SnS2@Ti3C2Tx sandwich structure with S vacancies through heterojunction engineering. Anchoring SnS2 to Ti3C2Txvia S–Ti–C bonds, this interlocking cooperative heterostructure not only mitigates Ti3C2Tx self-stacking but also exposes a significant number of active sites on the surface. Consequently, it improves the intercalation pseudocapacitance ratio, resolves the reaction kinetic hysteresis caused by the challenging removal of sodium ions, and prevents structural collapse resulting from the volume effect in SnS2. Moreover, the S vacancies effectively enhance the adsorption capacity of Na+, providing additional active sites for their adsorption. Density functional theory calculations demonstrate increased adsorption energy and reduced diffusion energy of sodium ions, thereby improving the sodium storage performance of the materials. The SnS2@Ti3C2Tx heterojunction exhibits an impressive reversible capacity of 225 mA h g−1 at 100 mA g−1, with 82% capacity retention after 1000 cycles. Furthermore, even at 500 mA g−1, a capacity of 122 mA h g−1 can still be achieved after 1000 cycles. Consequently, this research offers novel insights for future exploration in the development of anode materials for ion batteries.

Developing multifunctional materials with oil/water separation, dye adsorption, and antibacterial activities presents an enticing prospect for wastewater treatment. In this paper, a three-dimensional (3D) porous cellulose (CE)/quaternized cellulose (QCE) composite aerogel with super-wettability through co-deposition of polydopamine (PDA) and polyethylenimine (PEI) is reported. The PDA/PEI coating endows the aerogel with superhydrophilicity (WCA = 0°), and the QCE act as an anionic dye sorbent at the same time, endowing the material with antimicrobial activity against Escherichia coli (E. coli). Oil/water mixtures can be separated on an as-prepared aerogel with high efficiency (>99%), even when the filtration was repeated 10 times, and the as-prepared aerogel can also separate oil-in-water emulsions. Moreover, the as-prepared aerogel exhibited excellent adsorption performance for alizarin red, with a calculated maximum adsorption capacity of 454.545 mg g−1. Besides, our modification also endowed the aerogel with antibacterial and anti-oil-fouling activities. The inhibition zone test verified the efficient elimination of E. coli. This work may open a new avenue for designing versatile aerogel with multiple functions for waste water remediation.

The stability of a protease is crucial for its application in biological processes and various industries. This study aims to improve the stability of serine protease PB92 by introducing disulfide bonds. Using the Disulfide by Design 2 online server, we predicted appropriate cysteine pairs and introduced three pairs of amino acid mutations, resulting in their conversion to cysteines and subsequent formation of disulfide bonds. Additionally, to comprehensively assess the effects of combined mutations, three additional mutations were generated by combining the aforementioned three pairs of mutations. Molecular Dynamics (MD) simulations were performed to evaluate the influence of the introduced mutations. The results demonstrated that the mutant with disulfide residues A71C–A86C and T249C–L261C exhibited higher stability compared to both the wild type and other mutants. Docking results indicated that the introduced mutations did not affect the binding performance of the protease.

Catalytic oxidation is a widely used technology to eliminate undesired organic substances from water resources. Transition metal catalysts have a critical role to play in catalytic advanced oxidation; however, the toxicity of these catalysts is a major threat to human health and the environment. Therefore, research on the development of efficient oxidation catalysts with reduced toxicity is extremely critical. Herein, we report the catalytic investigation of hyaluronic acid-functionalized silver nanoparticles (HA-AgNPs) as an efficient and non-toxic catalyst in the degradation of morin dye as a model compound. The as-synthesized nanoparticles are characterized by different analytical methods such as ultraviolet-visible (UV-vis) spectroscopy, scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), dynamic light scattering (DLS) and zeta potential. The particle size and charge of the HA-AgNPs are found to be 23.9 ± 8.3 nm and −43.5 ± 0.8 mV, respectively. The catalytic activity of HA-AgNPs has been assessed in the oxidation of morin with H2O2. The catalytic studies reveal that the oxidation follows first order reaction kinetics with an apparent rate constant of 1.01 × 10−2 s−1 and the degradation of morin has been completed within 5 min, indicating outstanding catalytic properties of HA-AgNPs. The cytotoxicity of HA-AgNPs was further evaluated by MTT assay and the results show that these nanoparticles are non-toxic to MCF-10A non-tumorigenic breast epithelial cells and MCF-7 breast cancer cells.

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A graphical abstract is available for this content

Because anthrax spores are highly lethal to humans and animals as well as potential biological warfare agents, there is a great need for rapid, sensitive, and selective quantification of dipicolinic acid (DPA) as a biomarker for anthrax spores. Herein, we prepared a novel lanthanide-doped nanoprobe by coordination of Tb3+ ions with tannic acid (TA)-coated zeolitic imidazolate frameworks-8 (ZIF-8) (ZIF-8@Tb–TA). The proposed assay was derived from the unsaturated coordination of Tb3+ ions. In the presence of DPA, Tb3+ ions could be sensitized to emit inherent luminescence due to the energy transfer after coordination with DPA. The results illustrated that ZIF-8@Tb–TA could be used as a sensitive nanoprobe for detecting DPA with a broad linear range (0 μM to 12.0 μM), and the limit of detection (LOD) was 12.3 nM. Moreover, the specific recognition ability of DPA by ZIF-8@Tb–TA was much better than that of other interfering molecules. This study proposed a new strategy to establish lanthanide-functionalized nanoprobes for highly selective and sensitive detection of DPA.

We propose an electrode-free zinc manganese battery, where both zinc and MnO2 are electro-deposited from the electrolyte via a charging process onto carbon current collectors. The electrode-free batteries show an improved cycling performance of thin-film batteries than the ones with a zinc anode and a facilitated fabrication process for fiber batteries.

The development of chiral ligands to fine-tune stereocontrol in asymmetric catalysis is of great demand. To diversify the Py-2NO ligand library recently developed by our group, herein, we synthesized six new Py-2NO ligands, determined the absolute configuration via X-ray crystallographic study of ligand L1g, and applied these ligands in the Ni(II)-catalyzed asymmetric Michael addition reaction of indoles and β,γ-unsaturated α-keto esters. Excellent yields (up to 93%) and high enantioselectivities (up to 99% ee) were obtained for a wide range of substrates under mild conditions. In addition, we discovered the presence of axial chirality in the C(aryl)–N(amide) bond in the tertiary amine-derived N-oxide product via X-ray crystallographic study. Owing to the intriguing characteristics of atropisomerism, we believe that this reaction will add an important member to the axial chiral family.

Based on the inherent gain amplification ability of field-effect transistors (FETs), weak biological signals can be amplified. The present study unveils a pH sensor based on a carbon nanotube (CNT)-FET, which exhibits remarkable environmental stability. Moreover, we have successfully validated the feasibility of utilizing this CNT FET device for pH sensing, showcasing a remarkable sensitivity of Vth at 82 mV pH−1 and 87 mV pH−1 for pH ranges of 1–7 and 7–13, respectively, an extensive pH range spanning from 1 to 13, as well as minimal hysteresis measuring at 0.726 mA with pH switching loops ranging from 4.85–9.12. This research not only realizes high-performance pH sensors, but also lays the foundation for the development of FET biosensors with excellent environmental stability. This is essential to ensure that FET biosensors function properly in complex systems.

Perovskite oxides are considered promising efficient and cost-effective water splitting electrocatalysts under alkaline conditions because of their excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activity. However, due to their poor electron transfer and lack of exposed active sites, their HER activity is still much lower than that of precious metal catalysts. Besides, to date, few studies have been reported on the HER in complex water systems. In this study, a new composite electrocatalyst, SrCo0.7Fe0.3O3−δ@CdS, with a core–shell structure (denoted as SCF@CdS) was successfully prepared using an in situ coprecipitation method, which exhibited efficient HER activity in an alkaline environment and oilfield wastewater. The better electrocatalytic performance of SCF@CdS than pure SCF can be attributed to the larger specific surface area and more exposed active sites in this core–shell structure, and the lone pair electrons from S in CdS can also form coordination bonds with the vacant orbital of Co in the perovskite by sharing electron pairs, thus increasing the concentration of oxygen vacancies. This study provides a strategy to improve the HER performance of perovskite catalysts in complex water systems via the construction of a core–shell structure.

An efficient strategy to construct α-alkynyl ketones through electrochemical difunctionalization of alkenes was developed. This method is oxidant-free, metal-free, high-efficiency and eco-friendly, and offers rapid constructions of 1,2-alkynyl migration products through the radical process of 3-exo-dig cyclization. Moreover, the reaction could undergo a successful transformation under continuous-flow conditions.