Ammonia (NH3) production from electrocatalytic nitrate reduction reaction (NO3RR) is anticipated as a promising route to achieve both sustainable NH3 generation and nitrate water pollution removal. Herein, the molybdenum carbide (Mo2C) nanoclusters embedded in boron, nitrogen co-doped hollow carbon fibers (Mo2C@BNHCFs) electrocatalyst is fabricated for NO3RR by coaxial electrospinning and pyrolysis method. The uniformly dispersed Mo2C nanoclusters and the B, N doped-carbon layer provide more adsorption sites for nitrate reduction, effectively improving the activity and long-term stability of Mo2C@BNHCFs. Mo2C@BNHCFs-2 achieves a maximum NH3 yield of 6487.43 μg h-1 mgcat. -1 and Faradaic efficiency of 74.5% at -1.1 V (vs. reversible hydrogen electrode). Electrochemical in situ characterizations identify the formation of intermediates and products during the electrocatalytic NO3 - reduction process. Meanwhile, theoretical calculations indicate that electrons transfer from Mo2C nanoclusters to carbon supports can induce the creation of electron-deficient Mo2C, thus effectively activating the NO3 - and facilitating the electrochemistry process.

Oxide/elastomer composites combine the functional attributes of metal oxides with the mechanical deformability of elastomers, but face the challenge of balancing oxide loading and stretchability as ceramic fillers decrease the entropic elasticity of polymer networks. Here, we report an interfacial composite design that enables high oxide fraction and large stretchability by minimizing the contact area yet maximizing the binding strength between the oxide and elastomer. The elongation at break for an interfacial composite with 80 vol% of oxides reaches 500%, whereas that of a regular bulk composite with the same oxide fraction is 20%. These composites are synthesized based on a Marangoni co-assembly process with tuned interfacial tension and reaction at the water-oil interface. The assembly chemistry is nearly independent of oxides' sizes, compositions, geometries, and functions, making this interfacial structure broadly applicable to optical, electric, magnetic, and thermal-conducting oxides. Compared to bulk composites, the interfacial composites deliver larger magnetic actuation, lower thermal resistance, and higher conformability with nonplanar surfaces, providing rich implications for designing intelligent and electronic systems.

The corrosion of solid boric acid (s-BA) has so far remained unnoticed, which could pose a potential hazard to the safety of boron-containing equipment. In this work, a morphology-dependent corrosion behavior of s-BA was found on Q235 carbon steel encompassing temperatures from 160 °C to 240 °C. Concurrent with the corrosion process, s-BA underwent a heat-induced morphology-transition from block-like into sheet-like/flake-like under the delayed decomposition condition, which emerged as a key contributor to the heightened corrosion rates after reducing the volume of the corrosion system. Through integration with the ex-situ pretreatment experiment, our analysis concludes that this morphology-transition accelerated corrosion by facilitating the generation of more Fe5O5[B6O10(OH)3] ·nH2O and filamentous amorphous corrosion products than FeB12O19·5H2O. The crucial relationship between s-BA with distinct morphologies and different types of borate products was also further expounded.

PEO is one of the common composite polymer electrolyte vehicles; however, the presence of crystalline phase at room temperature, high interface impedance, and low oxidation resistance (<4.0 V) limit its application in stable all-solid-state lithium metal batteries. Herein, we designed a PEO-based solid polymer electrolyte (SPE) by adding boehmite nanoparticles to address the above-mentioned issues. Different-grain-sized boehmite nanoparticles were synthesized by adjusting the hydrothermal temperature. Moreover, the impacts of these distinct grain-sized boehmite nanoparticles used to fabricate boehmite/PEO polymer electrolytes (BPEs) on the performance of all-solid-state lithium metal batteries were investigated. It was found that with the increase in boehmite's grain size, BPEs show better performance. The best BPE exhibited an improved Li+ transference number (0.59), high ionic conductivity (1.25 x 10(-4) S m(-1)), and wide electrochemical window (similar to 4.5 V) at 60 degrees C. The assembled lithium symmetric battery can stably undergo 500 hours of lithium plating/stripping at 0.1 mA cm(-2). At the same time, the LiFePO4/BPE/Li battery exhibits excellent cycling stability after 100 cycles at 0.5C. This reasonable design strategy with a superior capacity retention rate (86%) demonstrates great potential in achieving high ionic conductivity and good interface stability for all-solid-state lithium metal batteries simultaneously.

With the aim to determine the potential corrosion effects of solid boric acid (BA) on light water reactors or other BA-involved equipment, the corrosion behaviors of solid BA on 304 stainless steel (SS) at different temperatures were investigated. Upon comparing the corrosion behaviors of solid BA at different temperatures, significant localized corrosion was observed on 304 SS surfaces at 150 °C following 90-day. This localized corrosion exhibited a characteristic pattern of scattered corrosion craters including B-containing Cr-rich oxides. These oxides were found to originate within micro-cracks, gradually evolving into scar-like protrusions within the craters. The proposed corrosion mechanisms entail the interactions between solid BA and chromium oxides/hydroxides, leading to the formation of B-containing Cr-rich oxides. Our findings offer insights into potential corrosion incidents and protective strategies for industries dealing with solid BA.

Complex morphologies in nature often arise from the assembly of elemental building blocks, leading to diverse and intricate structures. Understanding the mechanisms that govern the formation of these complex morphologies remains a significant challenge. In particular, the edge-base plate growth of biogenic crystals plays a crucial role in directing the development of intricate bioskeleton morphologies. However, the factors and regulatory processes that govern edge-base plate growth remain insufficiently understood. Inspired by biological skeletons and based on the soluble property of boric acid (BA) in both water and alcohols, we obtained a series of novel BA morphologies, including coccolith, and anemone biological skeletons. Here, we unveil the "inscribed circle effect", a concise mathematical model that reveals the underlying causative factors and regulatory mechanisms driving edge-base plate growth. Our findings illuminate how variations in solvent environments can exert control over the edge-base plate growth pathways, thereby resulting in the formation of diverse and complex morphologies. This understanding holds significant potential for guiding the chemical synthesis of bioskeleton materials.

Surface coating is a vital approach for addressing the aging of cathode materials in lithium-ion batteries. In this study, we synthesized various-phase alumina nanoparticles by subjecting boehmite to different temperatures and investigated the impact of these distinct alumina phases when used as a coating layer on the performance of nickel-rich cathode materials. Our findings demonstrate that any-phase Al2O3-coated cathode material shows enhanced electrochemical performance at a high operating voltage (4.5 V). These Al2O3 coatings effectively inhibit the side reactions resulting from direct contact between the active material and electrolyte, reduce the dissolution of transition metal ions, and facilitate the formation of a uniform solid electrolyte interface (SEI). Notably, the sub-stable-phase Al2O3-coated cathode materials exhibit better rate performance at low currents. The stable-phase alumina (alpha-Al2O3)-coated cathode material shows the best cycling stability with a capacitance retention of 85.1% after 100 cycles at 5C under 45 degrees C. And the alpha/theta-mixed-phase Al2O3-coated Nickel-rich cathodes (NCM) achieves excellent rate performance and cycling stability.

The demand for face masks is increasing exponentially,especiallywhen the coronavirus pandemic and particulate matter (PM) pollutionhave become serious concerns to public health. However, a lot of pressureis caused by the frequent replacement of traditional masks due tothe easy dissipation of electrostatic charge and the accumulationof pathogenic microorganisms. Herein, nanofibrous membranes with efficientinhibition of bacteria, potent air filtration, and reusability performance,consisting of polyacrylonitrile (PAN) nanofibers coated with chitosanquaternary ammonium salt (HACC), were successfully manufactured bysimple impregnation method and coaxial electrospinning, respectively.The bactericidal rate of the nanofibrous membranes to the attachedbacteria was as high as 99.9% due to the excellent bactericidal activityof the quaternary ammonium groups, which could also be proven by themicroscopic appearance of the bacterial cell membrane rupture. Thepermanent dipole charges provided by PAN nanofibers endowed as-preparednanofibrous membranes the capability to stably capture PM even whenthe static electricity disappeared. Moreover, the filtration capacityof nanofibrous membranes could still be close to the initial valueafter a simple washing, which was even unattainable by commercialfilters. These nanofibrous membranes are expected to replace traditionaldisposable filters to achieve long-life and reusability expectations.

Core-shell Fe3O4 @UiO-66-NH2 nanospheres with superior photocatalytic activity and photo-Fenton performance were synthesized using a layer-by-layer growth strategy. The synthesis involved the use of FeCl3, trisodium citrate, sodium acetate, ZrCl4, and 2-aminoterephthalic acid as raw materials, with mercaptoacetic acid serving as a modifier. Fe3O4 @UiO-66-NH2 demonstrated improved visible-light-driven photocatalytic performance in the oxidation degradation of Rhodamine B (RhB) in the presence of trace amounts of H2O2 under visible light irradiation. The Fe(II)/Fe(III) cycle was accelerated by the transfer of the photogenerated electrons (e-) from UiO-66-NH2 to Fe3O4, which in turn encouraged the Fenton reaction to produce hydroxyl radicals (center dot OH). With only 10 mmol/L H2O2, the removal rate of RhB approached 94% in 120 min. Furthermore, when exposed to visible light, Fe3O4 @UiO-66-NH2 exhibited 99% efficacious antibacterial activity against Escherichia coli and Staphylococcus aureus. Overall, the as-prepared Fe3O4 @UiO-66-NH2 core-shell nanospheres show promise for practical applications as photocatalysts for the degradation of organic pollutants and the inactivation of bacteria in wastewater.

Phototherapy and sonotherapy are recognized by scientific medicine as effective strategies for treating certain cancers. However, these strategies have limitations such as an inability to penetrate deeper tissues and overcome the antioxidant tumor microenvironment. In this study, a novel “BH” interfacial‐confined coordination strategy to synthesize hyaluronic acid‐functionalized single copper atoms dispersed over boron imidazolate framework‐derived nanocubes (HA‐NC_Cu) to achieve sonothermal–catalytic synergistic therapy is reported. Notably, HA‐NC_Cu demonstrates exceptional sonothermal conversion performance under low‐intensity ultrasound irradiation, attained through intermolecular lattice vibrations. In addition, it shows promise as an efficient biocatalyst, able to generate high‐toxicity hydroxyl radicals in response to tumor‐endogenous hydrogen peroxide and glutathione. Density functional theory calculations reveal that the superior parallel catalytic performance of HA‐NC_Cu originates from the CuN 4 C/B active sites. Both in vitro and in vivo evaluations consistently demonstrate that the sonothermal–catalytic synergistic strategy significantly improves tumor inhibition rate (86.9%) and long‐term survival rate (100%). In combination with low‐intensity ultrasound irradiation, HA‐NC_Cu triggers a dual death pathway of apoptosis and ferroptosis in MDA‐MB‐231 breast cancer cells, comprehensively limiting primary triple‐negative breast cancer. This study highlights the applications of single‐atom‐coordinated nanotherapeutics in sonothermal–catalytic synergistic therapy, which may create new opportunities in biomedical research.

Boric acid is widely used in human life and industrial production. However, few methods for solving the slow dissolution behavior of boric acid are reported. Based on the Density Functional Theory (DFT) analysis, a reasonable modulation strategy is proposed and an effective regulation method is obtained for preparing instant boric acid in this work. The DFT theoretical calculations and various characterizations explain the relation between the exposed surface of crystalline boric acid and its dissolution rate. The experiment results prove that the slow dissolution behavior of boric acid can be dramatically improved by regulating its exposed surface of crystalline particles. This work may fill the lack in the controllable regulation of boric acid crystalline structure and provide new perspectives for improving the dissolution rate of other crystalline products.

Diseases caused by bacterial infection have resulted in serious harm to human health. It is crucial to develop a multifunctional antibiotic-independent antibacterial platform for combating drug-resistant bacteria. Herein, titanium diboride (TiB2) nanosheets integrated with quaternized chitosan (QCS) and indocyanine green (ICG) were successfully prepared as a synergetic photothermal/photodynamic antibacterial nanoplatform (TiB2-QCS-ICG). The TiB2-QCS-ICG nanocomposites exhibit effective photothermal conversion efficiency (24.92%) and excellent singlet oxygen (1O2) production capacity simultaneously under 808 nm near-infrared irradiation. QCS improved TiB2 stability and dispersion, while also enhancing adhesion to bacteria and further accelerating the destruction of bacteria by heat and 1O2. In vitro experiments indicated that TiB2-QCS-ICG had excellent antibacterial properties with an inhibition rate of 99.99% against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA), respectively. More importantly, in vivo studies revealed that the nanoplatform can effectively inhibit bacterial infection and accelerate wound healing. The effective wound healing rate in the TiB2-QCS-ICG treatment group was 99.6% which was much higher than control groups. Taken together, the as-developed TiB2-QCS-ICG nanocomposite provides more possibilities to develop metal borides for antibacterial infection applications.

Nowadays, lithium-ion batteries are required to have a higher energy density and safety because of their wide applications. Current commercial separators have poor wettability and thermal stability, which significantly impact the performance and safety of batteries. In this study, a class of boehmite particles with different grain sizes was synthesized by adjusting hydrothermal temperatures and used to fabricate boehmite/polyacrylonitrile (BM/PAN) membranes. All of these BM/PAN membranes can not only maintain excellent thermal dimensional stability above 200 °C but also have good electrolyte wettability and high porosity. More interestingly, the BM/PAN membranes' thermal shutdown temperature can be adjusted by changing the grain size of boehmite particles. The lithium-ion batteries assembled with BM/PAN separators exhibit different thermal stability phenomena at 150 °C and have excellent rate performance and cycle stability at room temperature. After 120 cycles at 1C, the LiFePO4 half-cell assembled by the best BM/PAN separator has almost unchanged discharge capacity, whereas the capacity retention of Celgard 2325 is only about 85%. Meanwhile, the NCM523 half-cell assembled with the best BM/PAN separator shows superb cycle stability after 500 cycles at 8C, with a capacity retention of 79% compared with 56% for Celgard 2325.

Development of new metal-free heterogeneous catalysts has long been the focus of intense research interest. The integration of multifunctional monomers into the skeletons of porous organic polymers (POPs) provides an efficient pathway to achieve this goal. Herein, we rationally designed and successfully prepared a new Tröger's base (TB)-derived POPs by insertion of pillar[5]arene macrocycle as a positively auxiliary group. Combined the both merits of pillar[5]arene macrocycle and TB moiety, the as-prepared polymer was further explored as an effective metal-free heterogeneous catalyst and exhibited promoted catalytic performance in Knoevenagel condensation and CO2 conversion. This work provides a new strategy to fabricate metal-free heterogeneous catalysts based on macrocyclic POPs.

深入探究薄水铝石的粒径调控及其转变成氧化铝的热分解机理对精细氧化铝的合成具有重要意义.采用拟薄水铝石作为晶种辅助氢氧化铝水热调控薄水铝石颗粒尺寸,并探究了该方法的普适性;通过对不同粒径薄水铝石的煅烧实验及脱水过程进行动力学分析,探究粒径对薄水铝石转变过程的影响机理.结果表明:加入不同比例的拟薄水铝石晶种可以制备出平均粒径D50分别为2.02、0.96、0.66 μm的薄水铝石微晶,不同工艺生产的晶种具有相同的调控效果;不同粒径的薄水铝石的脱水过程受不同动力学反应机理控制,且随着粒径的减小,脱水过程的活化能逐渐降低.该研究为调变薄水铝石颗粒尺寸提供一条新的有效途径,为薄水铝石作为前驱体制备精细氧化铝提供理论基础.

In recent years, the synthesis of inorganic materials with different particle sizes and the structure–activity relationship of inorganic materials have been hot research topics in the materials chemistry field.

Based on the volatility and sublimation properties of boric acid, the corrosion behaviours of 304 stainless steel (SS) in boric acid-containing vapour over the boric acid aqueous solution and in the solution at high temperature were investigated. The results showed that the vaporized boric acid could cause or accelerate the formation of droplet-orientated scabs on the metal surfaces, which led to the formation of localized crust-like layers of corrosion products, whereas the boric acid in solution could only cause uniform corrosion with thin oxide layers formed on the metal surface. Prolonging the exposure duration or increasing the concentrations of boric acid in solution could accelerate the localized corrosion. The weight gains of 304 SS exposed to the vaporized boric acid reached 0.314 mg/cm 2 at 180 degrees C for 960 h, while it was 0.055 mg/cm 2 in the corresponding boric acid solution, being 5.7 times in weight changes. Furthermore, the possible corrosion pathway and formation mechanism of the corrosion products were proposed and discussed.

In order to develop a more simple and efficient method of alumina modified cathode materials,and improve the rate and cycle performance of lithium battery cathode materials,the preparation of nano-alumina slurry with Ammonium polyacrylate(PAANH4)as dispersant and the coating of nano-alumina on the cathode material LiNi0.8Co0.1Mn0.1O2 were stud-ied.Through the experiment,it was optimized that the particle size of nano-alumina was smaller and uniform,when the addi-tion amount of PAANH4 was 4%,and the milling time was 8 h.This nano-alumina slurry was used to modify the cathode ma-terial of lithium ion battery.It was found that the addition of alumina did not change the surface morphology,particle size and crystal structure of the cathode material.In the electrochemical performance test,when the alumina coating amount was 0.3%(mass fraction),better enhanced rate performance was obtained,and when the alumina coating amount was 0.5%(mass fraction),better cycling stability was obtained.At 1C rate,the capacity retention rates of uncoated and 0.5%(mass fraction)alumina-coated cathode materials were 75.61%and 84.93%after 100 times,respectively.

Facemasks play a significant role as personal protective equipment during the COVID-19 pandemic, but their longevity is limited by the easy dissipation of electrostatic charge and the accumulation of bacteria. In this study, nanofibrous membranes composed of polyacrylonitrile and chitosan biguanide hydrochloride (PAN@CGH) with remarkable antibacterial characteristics were prepared through the coaxial electrospinning process. Particulate matter could be efficiently captured by the fibrous membrane, up to 98 % or more, via polarity-dominated forces derived from cyano and amino groups. As compared commercial N95 masks, the PAN@CGH was more resistant to a wider variety of disinfection protocols. Additionally, the nanofibrous membrane could kill >99.99 % of both Escherichia coli and Staphylococcus aureus. Based on these characteristics, PAN@CGH nanofibrous membrane was applied to facial mask, which possessed an excellent and long-lasting effect on the capture of airborne particles. This work may be one of the most promising strategies on designing high-performance face masks for public health protection.

The electrocatalytic nitrogen reduction reaction (NRR) for ammonia (NH3) under ambient conditions is emerging as a potentially sustainable alternative to the traditional, energy-intensive Haber-Bosch process for ammonia production. Currently, metal-based electrocatalysts constitute the majority of reported NRR catalysts. However, they often suffer from the shortcomings of competitive reactions of nitrogen adsorp-tion/activation and hydrogen generation. Therefore, there is an urgent need to develop more environ-mentally friendly, low energy consumption, and non-polluting high-performance metal-free electrocatalysts. In this study, borocarbonitride (BCN) materials derived from boron imidazolate frame-work (BIF-20) were used to boost efficient electrochemical nitrogen conversion to ammonia under ambi-ent conditions. The BCN catalyst demonstrated excellent performance in 0.1 M KOH, with an ammonia yield of 21.62 lg h-1 mgcat-1 and a Faradaic efficiency of 9.88% at -0.3 V (Reversible Hydrogen Electrode, RHE). This performance is superior to most metal-free catalysts and even some metal catalysts for NRR. The 15N2/14N2 isotope labeling experiments and density functional theory (DFT) calculations showed that N2 can be adsorbed and converted to NH3 on the surface of BCN, and that the energy barrier can be significantly reduced by structural design for BCN. This work highlights the important role played by the presence of Lewis acid-base pairs in metal-free catalysts for enhancing electrochemical NRR performance. (c) 2023 Elsevier Inc. All rights reserved.