Bioclay Enzyme with Bimetal Synergistic Sterilization and Infectious Wound Regeneration.

Bacteria invasion is the main factor hindering the wound-healing process. However, current antibacterial therapies inevitably face complex challenges, such as the abuse of antibiotics or severe inflammation during treatment. Here, a drug-free bioclay enzyme (Bio-Clayzyme) consisting of Fe2+-tannic acid (TA) network-coated kaolinite nanoclay and glucose oxidase (GOx) was reported to destroy harmful bacteria via bimetal antibacterial therapy. At the wound site, Bio-Clayzyme was found to enhance the generation of toxic hydroxyl radicals for sterilization via cascade catalysis of GOx and Fe2+-mediated peroxidase mimetic activity. Specifically, the acidic characteristics of the infection microenvironment accelerated the release of Al3+ from kaolinite, which further led to bacterial membrane damage and amplified the antibacterial toxicity of Fe2+. Besides, Bio-Clayzyme also performed hemostasis and anti-inflammatory functions inherited from Kaol and TA. By the combination of hemostasis and anti-inflammatory and bimetal synergistic sterilization, Bio-Clayzyme achieves efficient healing of infected wounds, providing a revolutionary approach for infectious wound regeneration.

Mineral Phase Reconfiguration Enables the High Enzyme-like Activity of Vermiculite for Antibacterial Application.

Phyllosilicates-based nanomaterials, particularly iron-rich vermiculite (VMT), have wide applications in biomedicine. However, the lack of effective methods to activate the functional layer covered by the external inert layer limits their future applications. Herein, we report a mineral phase reconfiguration strategy to prepare novel nanozymes by a molten salt method. The peroxidase-like activity of the VMT reconfiguration nanozyme is 10 times that of VMT, due to the electronic structure change of iron in VMT. Density-functional theory calculations confirmed that the upward shifted d-band center of the VMT reconfiguration nanozyme promoted the adsorption of H2O2 on the active iron sites and significantly elongated the O-O bond lengths. The reconfiguration nanozyme exhibited nearly 100% antibacterial activity toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), much higher than that of VMT (E. coli 10%, S. aureus 21%). This work provides new insights for the rational design of efficient bioactive phyllosilicates-based nanozyme.

Significantly Enhanced the Energy Density of Dielectric Composites by Sandwich Structure with Highly Insulating Mica Nanosheets.

Dielectric polymer composites exhibit great application prospects in advanced pulse power systems and electric systems. However, the decline of breakdown strength by loading of single high dielectric constant nanofiller hinders the sustained increase in energy density of the composites. Here, a sandwich-structured nanocomposite prepared with mica nanosheets as the second filler exhibits decoupled modulation of dielectric constant and breakdown strength. The traditional layered clay mineral mica is exfoliated into nanosheets and filled into polyvinylidene difluoride (PVDF), which shows a special depolarization effect in the polymer matrix. In Kelvin probe microscopy characterization and thermally stimulated depolarization current indicates that the mica nanosheets provided space charge traps for the polymer matrix and effectively suppressed the carrier motion. A sandwich structure composite material with mica nanosheets as the central layer has achieved a high energy density of 11.48 J cm-3, 2.4 times higher than the pure PVDF film. This is due to the fact that randomly oriented distribution of nanosheets in a polymer matrix provide better current blocking. This work provides an effective method to improve the energy density of dielectric polymer composites by synergistically introducing insulating nanosheets and high dielectric constant nanofillers.

Roles of Oxygen-Containing Functional Groups in Carbon for Electrocatalytic Two-Electron Oxygen Reduction Reaction.

Recent years have witnessed great research interests in developing high-performance electrocatalysts for the two-electron (2e-) oxygen reduction reaction (ORR) that enables the sustainable and flexible synthesis of H2O2. Carbon-based electrocatalysts exhibit attractive catalytic performance for the 2e- ORR, where oxygen-containing functional groups (OFGs) play a decisive role. However, current understanding is far from adequate, and the contribution of OFGs to the catalytic performance remains controversial. Therefore, a critical overview on OFGs in carbon-based electrocatalysts toward the 2e- ORR is highly desirable. Herein, we go over the methods for constructing OFGs in carbon including chemical oxidation, electrochemical oxidation, and precursor inheritance. Then we review the roles of OFGs in activating carbon toward the 2e- ORR, focusing on the intrinsic activity of different OFGs and the interplay between OFGs and metal species or defects. At last, we discuss the reasons for inconsistencies among different studies, and personal perspectives on the future development in this field are provided. The results provide insights into the origin of high catalytic activity and selectivity of carbon-based electrocatalysts toward the 2e- ORR and would provide theoretical foundations for the future development in this field.

Breaking through the pH Limitation of Fe1-xS Nanozymes Using Component-Modulated Coupled Nanoclay.

Overcoming the intrinsic low activity of most peroxidase mimics under neutral pH is crucial but still extremely challenging for the detection of disease markers in biological samples. Here, we chose nanoclay (i.e., montmorillonite K10, MK10) as a carrier to modulate the structure of Fe1-xS nanozyme components through an interfacial modulation strategy, aiming at breaking the neutral pH limitation of Fe1-xS. MK10 with abundant hydroxyl groups on its surface acts as a carrier to increase the ratio of Fe(II) and S(II-) content in surface Fe1-xS. We verify that Fe(II)-promoted surface hydroxyl radical generation and S(II-)-promoted regeneration of Fe(II) play key roles in endowing peroxidase-like activity to Fe1-xS at neutral pH. As expected, Fe1-xS/MK10 exhibited 11-fold higher Vmax and 52-fold higher catalytic efficiency than bare Fe1-xS. As a proof of concept, the sensor constructed based on Fe1-xS/MK10 achieved colorimetric detection of xanthine under neutral conditions with a linear range of 5-300 µM and a limit of detection of 2.49 µM. Finally, we achieved highly sensitive detection of xanthine in serum using the constructed biosensor. Our contribution is the novel use of a nanoclay-mediated interfacial modulation strategy for boosting the peroxidase-mimicking activity and breaking the pH limitation, which contributes to the in situ detection of disease markers by nanozymes under physiological conditions.

Differential Adsorption of Dissolved Organic Matter and Phosphorus on Clay Mineral in Water-Sediment System.

Lake sediments connection to the biogeochemical cycling of phosphorus (P) and carbon (C) influences streamwater quality. However, it is unclear whether and how the type of sediment controls P and C cycling in water. Here, the adsorption behavior of montmorillonite (Mt) with different interlayer cations (Na+, Ca2+, or Fe3+) on dissolved organic matter (DOM) and P was investigated to understand the role of Mt in regulating the organic carbon-to-phosphate (OC/P) ratio within freshwater systems. The adsorption capacity of Fe-Mt for P was 3.2-fold higher than that of Ca-Mt, while it was 1/3 lower for DOM. This dissimilarity in adsorption led to an increased OC/P in Fe-Mt-dominated water and a decreased OC/P in Ca-Mt-dominated water. Moreover, an in situ atomic force microscope and high-resolution mass spectrometry revealed molecular fractionation mechanisms and adsorptive processes. It was observed that DOM inhibited the nucleation and crystallization processes of P on the Mt surface, and P affected the binding energy of DOM on Mt through competitive adsorption, thereby governing the interfacial P/DOM dynamics on Mt substrates at a molecular level. These findings have important implications for water quality management, by highlighting the role of clay minerals as nutrient sinks and providing new strategies for controlling P and C dynamics in freshwater systems.

Enhanced Adsorption of Trace Ethylene on Ag/NZ5 Modified with Ammonia: Hierarchical Structure and Metal Dispersion Effects.

Trace ethylene poses a significant challenge during the storage and transportation of agricultural products, causing over-ripening, reducing shelf life, and leading to food waste. Zeolite-supported silver adsorbents show promise for efficiently removing trace ethylene. Herein, hierarchical Ag/NZ5(X) adsorbents were prepared via different ammonia modifications, which featured enhanced ethylene adsorption ability. Ag/NZ5(2.5) exhibited the largest capacity and achieved near-complete removal at room temperature with prolonged efficacy. Characterization results indicated that the ammonia modification led to the formation of a hierarchical structure in the zeolite framework, reducing diffusion resistance and increasing the accessibility of the active sites. Additionally, desilication effects increased the defectiveness, generating a stronger metal-support interaction and resulting in a higher metal dispersion rate. These findings provide valuable insights into the development of efficient adsorbents for removing trace ethylene, thereby reducing food waste and extending the shelf life of agricultural products.

Layered Clay Minerals in Cancer Therapy: Recent Progress and Prospects.

Cancer is one of the deadliest diseases, and current treatment regimens suffer from limited efficacy, nonspecific toxicity, and chemoresistance. With the advantages of good biocompatibility, large specific surface area, excellent cation exchange capacity, and easy availability, clay minerals have been receiving ever-increasing interests in cancer treatment. They can act as carriers to reduce the toxic side effects of chemotherapeutic drugs, and some of their own properties can kill cancer cells, etc. Compared with other morphologies clays, layered clay minerals (LCM) have attracted more and more attention due to adjustable interlayer spacing, easier ion exchange, and stronger adsorption capacity. In this review, the structure, classification, physicochemical properties, and functionalization methods of LCM are summarized. The state-of-the-art progress of LCM in antitumor therapy is systematically described, with emphasis on the application of montmorillonite, kaolinite, and vermiculite. Furthermore, the property-function relationships of LCM are comprehensively illustrated to reveal the design principles of clay-based antitumor systems. Finally, foreseeable challenges and outlook in this field are discussed.

Nanoclay-Modulated Interfacial Chemical Bond and Internal Electric Field at the Co3 O4 /TiO2 p-n Junction for Efficient Charge Separation.

To achieve a high separation efficiency of photogenerated carriers in semiconductors, constructing high-quality heterogeneous interfaces as charge flow highways is critical and challenging. This study successfully demonstrates an interfacial chemical bond and internal electric field (IEF) simultaneously modulated 0D/0D/1D-Co3 O4 /TiO2 /sepiolite composite catalyst by exploiting sepiolite surface-interfacial interactions to adjust the Co2+ /Co3+ ratio at the Co3 O4 /TiO2 heterointerface. In situ irradiation X-ray photoelectron spectroscopy and density functional theory (DFT) calculations reveal that the interfacial Co2+ OTi bond (compared to the Co3+ OTi bond) plays a major role as an atomic-level charge transport channel at the p-n junction. Co2+ /Co3+ ratio increase also enhances the IEF intensity. Therefore, the enhanced IEF cooperates with the interfacial Co2+ OTi bond to enhance the photoelectron separation and migration efficiency. A coupled photocatalysis-peroxymonosulfate activation system is used to evaluate the catalytic activity of Co3 O4 /TiO2 /sepiolite. Furthermore, this work demonstrates how efficiently separated photoelectrons facilitate the synergy between photocatalysis and peroxymonosulfate activation to achieve deep pollutant degradation and reduce its ecotoxicity. This study presents a new strategy for constructing high-quality heterogeneous interfaces by consciously modulating interfacial chemical bonds and IEF, and the strategy is expected to extend to this class of spinel-structured semiconductors.

Integrating Structural and Thermodynamic Mechanisms for Methanol Intercalated Kaolinite Nanoclay: Experiments and Density Functional Theory Simulation.

Methanol intercalated kaolinite (Kaol) plays an important role in the intercalation, exfoliation, and organic modification of kaolinite nanoclay. However, the evolution of the layer structure of Kaol and its thermodynamic stability during the methanol intercalation process have not been clarified at the atomic level. Here, by combination of density functional theory (DFT) calculation and experimental characterizations, the interlayer bonding, structure evolution, and energetics from dimethyl sulfoxide (DMSO) intercalated Kaol to methanol intercalated Kaol were investigated. Partial methanol molecules entered the interlayers of Kaol to form some intermediate structures with the same d-spacing as that of DMSO intercalated Kaol. Different numbers of grafted methoxy and water molecules coexist together in the interlayer to form the final structures of methanol intercalated kaolinite (MeOm/nH2O/Kaol). The whole intercalation process is energy-consuming, and the presence of DMSO would affect the intercalation of methanol. Meanwhile, the formation energy from intermediate structures to final structures was found reduced under the participation of water.

Emerging Phosphate-Functionalized Co3O4/Kaolinite Composites for Enhanced Activation of Peroxymonosulfate.

The Fenton-like reaction, as one of the most efficient strategies to generate radical species for the degradation of environmental pollutants, has attracted considerable attention. However, engineering low-cost catalysts with excellent activity by phosphate surface functionalization has seldom been used for the activation of peroxymonosulfate (PMS). Herein, emerging phosphate-functionalized Co3O4/kaolinite (P-Co3O4/Kaol) catalysts have been prepared by hydrothermal and phosphorization. Kaolinite nanoclay with rich hydroxyl groups plays a vital role in realizing phosphate functionalization. The results indicate that P-Co3O4/Kaol shows superior catalytic performance and excellent stability to the degradation of Orange II, which could be attributed to the existence of phosphate that promotes the adsorption of PMS and the electron transfer of Co2+/Co3+ cycles. Furthermore, the •OH radical was identified as the dominating reactive species for the degradation of Orange II compared to the SO4•- radical. This work could offer a novel preparation strategy for emerging functionalized nanoclay-based catalysts for effective pollutant degradation.

Understanding the Nanoscale Affinity between Dissolved Organic Matter and Noncrystalline Mineral with the Implication for Water Treatment.

In recent decades, the concentration of dissolved organic matter (DOM) in aquatic ecosystems has gradually increased, leading to water pollution problems. Understanding the interfacial chemical processes of DOM on natural minerals is important to the exploration of high-efficiency absorbents. However, studying DOM chemical processes and adsorption mechanisms are still challenging due to the complex DOM structure and environmental system. Hence, we characterized the microstructure changes after the formation of amorphous calcium phosphate (ACP) at the interface of montmorillonite (Mt) minerals in a simulated environment system. Combined with atomic force microscopy and density functional theory (DFT) simulation, the mechanism of interfacial interaction between Mt-ACP and DOM was characterized at the molecular level. Moreover, we further evaluated the adsorption behavior of Mt-ACP as a potential adsorbent for organic matter. The comprehensive investigation of humic acid adsorption, intermolecular force, and DFT simulation is conducive to our understanding of the interfacial interaction mechanism between organic matter and noncrystalline minerals in aquatic environments and provides new perspectives on the application of clay-based mineral materials in pollutant removal under exposure from DOM.

Mineral-Enhanced Manganese Ferrite with Multiple Enzyme-Mimicking Activities for Visual Detection of Disease Markers.

Local geometric configurations of metal cations in inorganic enzyme mimics determine their catalytic behaviors, while their optimization remains challenging. Herein, kaolinite, a naturally layered clay mineral, achieves the optimization of cationic geometric configuration in manganese ferrite. We demonstrate that the exfoliated kaolinite induces the formation of defective manganese ferrite and makes more iron cations fill into the octahedral sites, significantly enhancing the multiple enzyme-mimicking activities. The steady-state kinetic assay results show that the catalytic constant of composites toward 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2 are more than 7.4- and 5.7-fold higher than manganese ferrite, respectively. Furthermore, density functional theory (DFT) calculations reveal that the outstanding enzyme-mimicking activity of composites is attributed to the optimized iron cation geometry configuration, which has a higher affinity and activation ability toward H2O2 and lowers the energy barrier of key intermediate formation. As a proof of concept, the novel structure with multiple enzyme-mimicking activities amplifies the colorimetric signal, realizing the ultrasensitive visual detection of disease marker acid phosphatase (ACP), with a detection limit of 0.25 mU/mL. Our findings provide a novel strategy for the rational design of enzyme mimics and an in-depth investigation of their enzyme-mimicking properties.

Interfacial Chemical Bond Modulation of Co3(PO4)2-MoO3-x Heterostructures for Alkaline Water/Seawater Splitting.

The development of a high current density with high energy conversion efficiency electrocatalyst is vital for large-scale industrial application of alkaline water splitting, particularly seawater splitting. Herein, we design a self-supporting Co3(PO4)2-MoO3-x/CoMoO4/NF superaerophobic electrode with a three-dimensional structure for high-performance hydrogen evolution reaction (HER) by a reasonable devise of possible "Co-O-Mo hybridization" on the interface. The "Co-O-Mo hybridization" interfaces induce charge transfer and generation of fresh oxygen vacancy active sites. Consequently, the unique heterostructures greatly facilitate the dissociation process of H2O molecules and enable efficient hydrogen spillover, leading to excellent HER performance with ultralow overpotentials (76 and 130 mV at 100 and 500 mA cm-2) and long-term durability of 100 h in an alkaline electrolyte. Theoretical calculations reveal that the Co3(PO4)2-MoO3-x/CoMoO4/NF promotes the adsorption/dissociation process of H2O molecules to play a crucial role in improving the stability and activity of HER. Our results exhibit that the HER activity of non-noble metal electrocatalysts can be greatly enhanced by rational interfacial chemical bonding to modulate the heterostructures.

Nanoscale Interactions of Humic Acid and Minerals Reveal Mechanisms of Carbon Protection in Soil.

The concentrations of terrestrially sourced dissolved organic matter (DOM) have expanded throughout aquatic ecosystems in recent decades. Although sorption to minerals in soils is one major pathway to sequestrate soil organic matter, the mechanisms of organic matter-mineral interactions are not thoroughly understood. Here, we investigated the effect of calcium phosphate mineralization on humic acid (HA) fixation in simulated soil solutions, either with or without clay mineral montmorillonite (Mt). We found that Mt in solution promoted nucleation and crystallization of calcium phosphate (CaP) due to amorphous calcium phosphate clustering and coalescence on Mt surface, which contributed to the long-term persistence and accumulation of HA. Organic ligands with specific chemical groups on HA have higher binding energies to CaP-Mt than to CaP/Mt, according to dynamic force spectroscopy observations. Moreover, CaP-Mt formed in solution showed a great capacity for HA adsorption with a maximum adsorption quantity of 156.89 mg/g. Our findings directly support that Mt is crucial for DOM sequestration by facilitating CaP precipitation/transformation. This has an impact on how effectively we understand the long-term turnover of DOM and highlights knowledge gaps that might assist in resolving essential soil C sequestration issues.

Determination of metabolisable and net energy contents of corn fed to Arbor Acres broilers and Beijing You chickens.

This study was done to compare the energy and nutrient utilisation of corn in Arbor Acres (AA) broilers and Beijing You (BJY) chickens. BJY chickens with the same age as AA broilers were named BJY1 chickens, and with the same body weight as AA broilers were named BJY2 chickens. Three groups of broilers (36 male AA broilers, 72 male BJY1 chickens, and 36 male BJY2 chickens), 2 treatments per group, 6 replicates per treatment, 3 chickens or 6 chickens per replicate. During each period, birds were fed in chambers for 11 days, including 5 days for adaptation to the feed, 3 days for excreta and gas data collection and another 3 days for fasting were recorded. Results showed that the fasting heat production (FHP) of AA, BJY1 and BJY2 chickens gradually stabilised after fasting for 72 h, the FHP of AA, BJY1 and BJY2 chickens were 486.54, 536.22 and 548.90 KJ/kg BW0.70 /day respectively. AA broilers had significantly lower (p < 0.01) apparent total tract digestibility (ATTD) of starch in corn than that of BJY1 and BJY2 chickens, whereas there were no significant differences (p > 0.05) observed in ATTD of dry matter, crude protein, ether extract and crude fibre. The apparent metabolisable energy (AME) values of corn in AA, BJY1 and BJY2 chickens were 16.18, 16.81, and 16.39 MJ/kg dry matter (DM) and the corresponding nitrogen-corrected AME (AMEn) values were 15.71, 16.38 and 15.99 MJ/kg DM respectively. The net energy (NE) values of corn in AA, BJY1 and BJY2 chickens were 12.03, 12.28 and 11.97 MJ/kg DM respectively. In conclusion, BJY chickens had a higher maintenance energy requirement than that of AA broilers, and AA broilers of the same age and weight as BJY chickens showed no significant differences in AME, AMEn and NE values of corn.

Nutrient utilisation, metabolisable and net energy values of corn for broiler chickens during the starter and grower phases.

The objective of this experiment was to determine the energy values and nutrient utilisation of five corns at starer (14-16 days) and grower (28-30 days) phases. The 1-5 corn samples were obtained from Jinzhou, Liaoning; Gongzhuling, Jilin; Qingdao, Shandong; Songyuan, Jilin and Xinxiang, Henan, China. Each phase of the trial consisted of six treatments with six replicates each. The number of birds per replicate was 4 (Days 14-16) and 2 (Days 28-30). Diets included a corn-soybean meal basal diet and five test diets contained 30% of each corn sample, which replaced 30% of the energy-yielding components of the basal diet (as-fed basis). The trial consisted of six cycles, each cycle was 7 days, including 4 days for adaptation to feed. On Day 4, the birds were transferred to the respiration chambers. In the following 3 days, total excreta were collected and daily heat production was measured. The apparent total tract retention of dry matter, crude protein, ether extract, and starch improved with age, showing the same trend as energy values. The nitrogen-corrected metabolisable energy (AMEn) values for corn samples at the starter phase were in the range of 16.25-17.41 MJ/kg DM and at the grower phase were in the range of 17.23-17.60 MJ/kg DM. On the other hand, the net energy (NE) values of the five corn samples ranged from 9.93 to 11.67 MJ/kg DM during the starter period and from 11.19 to 12.27 MJ/kg DM during the grower period. The AMEn and NE values of the five corn samples were close to the literature values for corn. Results from our research indicated the nutrient digestibility and energy values of corn samples increase with the age of the broiler.

Pd/Fe2O3 with Electronic Coupling Single-Site Pd-Fe Pair Sites for Low-Temperature Semihydrogenation of Alkynes.

Dispersing single palladium atoms on a support is promising to minimize the usage of palladium and improve the selectivity for alkyne semihydrogenation, but its activity is often very low as a result of unfavorable H2 activation. Here, we load palladium onto α-Fe2O3(012) to construct highly active and stable single-site Pd-Fe pairs with luxuriant d-electron domination near the Fermi level driven by strong electronic coupling and prove that Pd-Fe pairs cooperatively adsorb H2 and dissociate an H─H bond, whereas solo Pd sites enable preferential desorption of C═C intermediate, thus achieving both high activity and high selectivity for alkyne hydrogenation. This catalyst exhibits state-of-the-art performance in purifying acetylene of ethylene stream, with 99.6% and 100% conversion and 96.7% and 94.7% selectivity at 353 and 393 K, respectively, and excellent stability with negligible activity decay after a 200 h test. This single-site pair inherits the advantage but overcomes the weakness of both Pd ensemble and single Pd atoms, enabling ultralow-Pd-loading catalysts for selective hydrogenation.

Surface Design Strategy of Catalysts for Water Electrolysis.

Hydrogen, a new energy carrier that can replace traditional fossil fuels, is seen as one of the most promising clean energy sources. The use of renewable electricity to drive hydrogen production has very broad prospects for addressing energy and environmental problems. Therefore, many researchers favor electrolytic water due to its green and low-cost advantages. The electrolytic water reaction comprises the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). Understanding the OER and HER mechanisms in acidic and alkaline processes contributes to further studying the design of surface regulation of electrolytic water catalysts. The OER and HER catalysts are mainly reviewed for defects, doping, alloying, surface reconstruction, crystal surface structure, and heterostructures. Besides, recent catalysts for overall water splitting are also reviewed. Finally, this review paves the way to the rational design and synthesis of new materials for highly efficient electrocatalysis.

Manipulating the Conversion Kinetics of Polysulfides by Engineering Oxygen p-Band of Halloysite for Improved Li-S Batteries.

Polar oxides are widely used as the cathodes to impede the shuttle effect in lithium-sulfur batteries, but suffer from the sluggish desorption and conversion of polysulfides due to too strong affinity of polysulfides on oxygen sites. Herein, employing halloysite as a model, an approach to overcome these shortcomings is proposed via engineering oxygen p-band center by loading titanium dioxide nanoparticles onto Si-O surface of halloysite. Using density functional theory calculations, it is predicted that electron transfer from titanium dioxide nanoparticles to interfacial O sites results in downshift of p-band center of O sites that promote desorption of polysulfides and the cleavage of Li-S and S-S, accelerating the conversion kinetics of polysulfides. The designed composite cathode material delivers outstanding electrochemical performance in Li-S batteries, outperforming the recently reported similar cathodes. The concept could provide valuable insight into the design of other catalysts for Li-S batteries and beyond.