Search

Fatal dendritic growth in lithium metal batteries is closely related to the composition and thickness of the modified separator. Herein, an ultrathin nanocoating composed of monolayer montmorillonite (MMT), poly(vinyl alcohol) (PVA) on a polypropylene separator is prepared. The MMT was exfoliated into monolayers (only 0.96 nm) by intercalating PVA under ultrasound, followed by cross-linking with glutaraldehyde. The thickness of the nanocoating on the polypropylene separator, as determined using the pull-up method, is only 200–500 nm with excellent properties. As a result, the lithium-symmetric battery composed of it has a low overpotential (only 40 mV) and a long lifespan of more than 7900 h at high current density, because ion transport is unimpeded and Li+flows uniformly through the ordered ion channels between the MMT layers. Additionally, the separator exhibited excellent cycling stability in Li–S batteries. This study offers a new idea for fabricating ultrathin clay/polymer modified separators for metal anode stable cycling at high current densities.

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 Vmaxand 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.

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.

Phosphogypsum (PG)-derived CaSO4·2H2O is employed as a multifunctional protective layer to achieve dendrite-free Zn deposition. This artificial layer provides fast channels for Zn2+ions transportation.

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 H2O2are 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 H2O2and 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.

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.

Constructing efficient photocatalysts for the degradation of antibiotics was highly challenging. The support carrier played an active role in the reactivity, adsorption and lifetime of the catalyst. Herein, BiOCl/Mt photocatalysts were successfully prepared on a large scale by mixing natural iron-rich montmorillonite (Mt), bismuth nitrate, ethylene glycol (EG) and deionized water at room temperature. The optimal mass ratio of BiOCl/Mt was 1 : 1, and it could degrade 95.9% tetracycline hydrochloride (TCH) within 60 minutes. Compared with that of pure BiOCl, the degradation rate and kinetic constant were increased by 39% and 3.4 times, respectively. This was due to the fact that BiOCl/Mt has a smaller band gap and more positive valence potential than pure BiOCl, indicating a higher utilization efficiency of light and a stronger oxidation capability of holes (h+). The leading role of holes in TCH degradation was confirmed by free radical trapping experiments. In addition, the potential intermediates were identified by liquid chromatography-mass spectrometry, and ECOSAR software predicted that more than half of the products were less toxic than TCH molecules. This study demonstrated that iron-rich Mt not only was a carrier but also participated in the photocatalytic reaction as a p-type semiconductor and formed a p–n heterojunction with n-type semiconductor BiOCl, which significantly improved the photocatalytic ability of BiOCl/Mt.

Sodium metal has shown great potential as an inexpensive anode for rechargeable batteries. However, the growth of sodium dendrites continues to hinder the commercialization of Na metal batteries. Herein, an effective strategy using anion-anchoring halloysite nanotube (HNT) coating was proven to prevent the diffusion of anions and trigger uniform Na deposition. Through theoretical calculation, a model of active site of fixed anions exposed from HNTs after acid activation was established for the first time, revealing that Si–Al sites are effective active site of acid-activated HNTs. Furthermore, HNTs with strong and effective adsorption capacity for anions were obtained by controlling the structure of HNTs to regulate the exposure of Si–Al sites. The strong interaction between sites of acid-activated HNTs and the SO3CF3−anion effectively promotes the dissociation of sodium salts, the release of Na+and subsequent migration. As a result, HNTs acid activation for 4 h shows a steady sodium deposition process and displays high Coulombic efficiency in half cell, long cycle life in symmetric cell and full cell. This work provides a basic theoretical basis for the design of nanoclay with abundant and effective active site to fix anions for dendritic free metal batteries.

With the rapid development of electronics toward integration and miniaturization, efficient and accurate removal of excess energy from electronics has become a major challenge. In this study, a novel expanded graphite-based composite phase change film (EL) with high thermal conductivity was synthesized to facilitate the heat dissipation of electronic devices. The expanded graphite was compressed into a thin film and then impregnated with lauric acid (LA) to form EL. The effect of pressure on the thermal performance of EL was investigated. The results show that the latent heat storage capacity of composite phase films increases with the decrease in pressure. The melting and cooling enthalpy of EL-0 reach up to 111.6 and 107.9 J/g, respectively. Meanwhile, the corresponding in-plane thermal conductivity and axial thermal conductivity reach up to 21.28 W/(m·K) and 9.70 W/(m·K), which are 54.6 and 24.9 times those of the pure LA, respectively. It is interesting that the introduction of a phase change material (PCM) improves the axial thermal conductivity in comparison with the expanded graphite film without the PCM. The obtained EL exhibits excellent leakage-proof property and long-term thermal reliability. Last, the EL utilized in the thermal management of the graphics processing unit of the laptop running decreased the temperature by 5.0 °C, implying a potential application in the thermal management of electronics.

Iron-based catalysts are considered to be an important and promising transition metal catalyst. However, although the developed iron-based catalysts have good catalytic activity for peroxymonosulfate (PMS), their complex synthesis process, high cost and difficult recovery limit their large-scale application. In this work, a high performance, environmentally friendly and easily recyclable catalyst was prepared by anchoring iron tailings into electrospun fibers (EF). The electrospun membranes of iron tailings (EF-iron tailings) could activate PMS for degradation of organic pollutants under visible light. During reaction process, visible light accelerated the valence state transition of iron, which was conducive to the activation of PMS. The degradation mechanism showed that hydroxyl radical (·OH), superoxide radical (·O2−) and singlet oxygen (1O2) were the main active species, and·O2−and 1O2seemed to be more important for degradation. The application assessment in natural water confirmed potential practical application value of the EF-iron tailings membrane. The leaching test showed that the iron leaching amount of the EF-iron tailings membrane was low in the reaction process, meeting environmental requirements. This work provides an effective green preparation strategy of efficient solid waste-based catalyst with pro-environment and easy recycling.

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 H2O2on 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. coli10%, S. aureus21%). This work provides new insights for the rational design of efficient bioactive phyllosilicates-based nanozyme.

Sodium metal is one of the most promising anodes for the prospective low-cost rechargeable batteries. Nevertheless, the commercialization of Na metal anodes remains restricted by sodium dendrite growth. Herein, halloysite nanotubes (HNTs) were chosen as the insulated scaffolds, and Ag nanoparticles were introduced as sodiophilic sites to achieve uniform sodium deposition from bottom to top under the synergistic effect. Density functional theory (DFT) calculation results demonstrated that the presence of Ag greatly increased the binding energy of sodium on HNTs/Ag (−2.85 eV) vs HNTs (−0.85 eV). Meanwhile, thanks to the opposite charges on the inner and outer surfaces of HNTs, faster Na+transfer kinetics and selective adsorption of SO3CF3–on the inner surface of HNTs were achieved, thus avoiding the formation of space charge. Accordingly, the coordination between HNTs and Ag afforded a high Coulombic efficiency (about 99.6% at 2 mA cm–2), long lifespan in a symmetric battery (for over 3500 h at 1 mA cm–2), and remarkable cycle stability in Na metal full batteries. This work offers a novel strategy to design a sodiophilic scaffold by nanoclay for dendrite-free Na metal anodes.

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.

Pristine halloysite nanotubes (HNTs) were pretreated to produce mesoporous silica nanotubes (MSiNTs), which was further impregnated with polyethenimine (PEI) to prepare an emerging nanocomposite MSiNTs/PEI (MP) for CO2capture. Thermogravimetric analysis (TGA) was employed to analyze the influences of PEI loading amount and adsorption temperature on CO2adsorption capacity of the nanocomposite. The Brunauer–Emmett–Teller (BET) surface area (SBET) of MSiNTs was six times higher than that of HNTs, and the corresponding pore volume was more than two times higher than that of HNTs. The well dispersion of PEI within the nanotubes of MSiNTs benefits more CO2gas adsorption, and the adsorption capacity of the nanocomposite could reach 2.75 mmol/g at 85 °C for 2 h. The CO2adsorption on the nanocomposite was demonstrated to occur via a two-stage process: initially, a sharp linear weight increase at the beginning, and then a relatively slow adsorption step. The adsorption capacity could reach as high as 70% within 2 min. Also, the nanocomposite exhibited good stability on CO2adsorption/desorption performance, indicating that the as-prepared emerging nanocomposite show an interesting application potential in the field of CO2capture.

A novel Cu–Cu2O/TiO2/Ti electrode for the nonenzymatic electro-oxidation of glucose has been fabricated by secondary anodic oxidation combined with the electrodeposition method. It represents a new type of copper oxide–TiO2complex nanostructure that demonstrates a new application. At the potential range from −1.0 to −1.6 V, Cu2+was electrochemically reduced to Cu2O, accompanied by the simultaneous formation of Cu covering the top surface of the TiO2nanotubes. The highest response current was obtained at the optimized fabrication conditions with a deposition charge of 1.5 C, a pH of 12, 4 mM CuSO4, and a deposition potential of −1.4 V. The results indicate that Cu2O helps to keep a broad linear range, and the incorporation of Cu nanoparticles improves the response current and sensitivity. The linearity between the response current and the glucose concentration was obtained in the range from 0.1 to 2.5 mM with a sensitivity of 4895 μA cm–2mM–1. Such high sensitivity was attributed to the synergistic effect of the small Cu–Cu2O grain size and the large surface area of the helical TiO2nanotube arrays as well as the fast electron transfer. Electrochemical impedance spectroscopy has been successfully applied to explain the differences among different electrode interfaces and the change rule of nonenzymatic electro-oxidation properties.

Nickel phosphides are competitive non-noble candidates for alkaline hydrogen evolution reaction (HER), however, their activities are insufficient due to the inert alkaline water dissociation, which hampers application in hydrogen production. Herein, we design a highly efficient electrocatalyst consisting of monocrystalline NiMoO4nanorods modified by broccoli-like hierarchical Ni(PO3)2-Ni2P coupling with MoOxself-supported catalyst. As HER proceeds, catalytic performance gets better due to the dissolution of MoOxto further expose more nickel sites as Lewis base sites and in-situ formation of hydroxyl-ligands on the surface of loading nanoparticle as Lewis acid sites, which effectively integrate artificial frustrated Lewis pairs (FLPs) to respectively promote adsorption of H* and activation of H2O molecules. Moreover, the electron-transfer leads to the downshift of the d-band center of Ni, which helps optimizing desorption ability of H* . Therefore, such reconstructed catalyst exhibits extremely low overpotentials of 11 and 79 mV to afford 10 and 100 mA·cm−2in 1.0 M KOH with sustainable durability for over 110 h, outperforming most of reported advanced alkaline HER catalysts. Additionally, this catalyst used as cathode for overall alkaline water splitting at 10 and 100 mA·cm−2with only 1.48 and 1.57 V, showing its broad application prospect in practical large-scale hydrogen production.

Dry grinding of illite particles has been investigated by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption techniques. Prolonged grinding results in an amorphous illite structure and the mechanochemical effect markedly promotes a reduction in reflection intensities with increased grinding time. It is confirmed that illite is very susceptible to alteration by grinding. The illite crystal size (d006) appears to reach a limit after 2 h of grinding. N2adsorption studies indicate that illite ground for 8 h shows a larger average pore diameter than a sample after 4 h grinding or the original illite. It is inferred that grinding is good for the formation of macrostructural pores. Illite grinding results in a decrease in the Brunauer‐Emmet‐Teller (BET) surface area and total pore volume. IR spectroscopy shows a slight alteration in the illite bands after mechanochemical processing and some new bands were detected after 4 or more hours of grinding.

CdO nanoparticles of 43 nm in crystal size were successfully synthesized by the mechanochemical reaction (CdCl2+ Na2CO3) with NaCl as a diluent and subsequent thermal treatment at 700°C for 2 h. The samples were characterized by differential thermal analysis (DTA), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Effect of calcination temperature on the crystal size of CdO nanoparticles was primarily investigated. The apparent activation energy of CdO nanoparticle formation during thermal treatment was calculated to be 12.2 kJ/mol.

The oxidation behaviors of non-activated and mechanically activated galenas were investigated by thermogravimetry method (TG) in flowing highly pure oxygen atmosphere at the heating rate of 10 K min. It is found that the mass increase between 400 and 850 K in the TG curves rises with the increase of grinding time of galena. The difference in oxidation reactivity of non-activated and mechanically activated galenas was also discussed. The specific granulometric surface area ( S G ) and the structural disorder of mechanically activated galenas were analyzed by X-ray diffraction laser particle size analyzer and X-ray powder diffraction analysis (XRD), respectively. The results show that the specific granulometric surface area ( S G ) of mechanically activated galenas almost remains constant after grinding for a certain period, and lattice distortions ( a˚ ) increase, but the crystallite sizes ( D ) decrease with the increase of the grinding time. All the results imply that the mass increase between 400 and 850 K in the TG curves for mechanically activated galenas is mainly caused by the increase of lattice distortions ( a˚ ) and the decrease of the crystallite sizes ( D ) with increasing the grinding time.

Cobalt ferrite (CoFe2O4) nanoparticles have been prepared by chemical coprecipitation, mechanical milling and subsequent thermal treatment. Sodium chloride was added as a diluent during mechanical milling to avoid agglomeration of the particles. Thermal treatment of the as-milled powder at 600 °C produces well-crystallized CoFe2O4nanoparticles with an average crystal size of 22.5 nm. The mechanism of nanoparticle growth was discussed.