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Engine exhaust pollutants have caused serious environmental pollution and harm to human health. As the most effective and economical technology to control pollutants in engine exhaust, catalytic purification technology has become a focus of current research. The development of low-cost and efficient catalysts is the decisive factor for the widespread application of catalytic purification technology. In recent years, transition metal-modified zeolite catalysts have been widely used to eliminate engine exhaust pollutants because of their low cost, high activity, and high stability. This article introduces the preparation methods for a series of transition metal-modified zeolites, such as Fe-modified, Cu-modified, Mn-modified, Ti-modified, Co-modified, and bimetal-modified zeolites. Meanwhile, the research progress of transition metal-modified zeolite catalysts for removing pollutants, such as nitrogen oxides, soot particles, volatile organic compounds, carbon monoxide, methane, etc., has also been summarized in detail. Finally, the problems and future development tendencies of transition metal-modified zeolite catalysts for the catalytic elimination of engine exhaust pollutants have been proposed. [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotubes (SWCNTs) possess superb properties originating from their unique chiral structures. However, accurately controlling the structure of SWCNTs remains challenging due to the structural similarities of their chiral structures, which hinders their widespread application in various fields, particularly in electronics. In recent years, much effort has been devoted to preparing single chiral SWCNTs by adopting three constructive strategies, including growth condition control for structurally unstable liquid catalysts, employing stable solid catalyst design, and pre-synthesis of carbon seeds with a well-defined shape. This review comprehensively discusses the state-of-the-art developments in these approaches as well as their advantages and disadvantages. Moreover, insights into the key challenges and future directions are provided for acquiring chirally pure SWCNTs. [ABSTRACT FROM AUTHOR]

The determination of the composition and timing sequence of products during the detonation of energetic materials is crucial for the evaluation of detonation performance and improvement of the formulation. However, it is difficult to determine the detonation products of energetic materials due to the fast reaction time during detonation. Herein, a new setup is built to detect the detonation products of energetic materials by time correlated laser induced plasma spectroscopy (LIPS) combined with high-speed schlieren imaging. The characteristics of time resolution and spatial distribution of propellant products from laser induced micro-detonation are obtained using the system. According to the time resolved spectrum of the products and high-speed schlieren images of laser induced micro-detonation, we speculate on the timing sequence of gaseous propellant products from laser induced micro-detonation in air: N2, O2, and nitrogen oxides precede hydrocarbon gases, followed by carbon oxides and gaseous containing the element of H. Moreover, the distribution of the gaseous products from laser induced micro-detonation are clarified. This study provides a new method for the detection of products during the detonation of energetic materials. [ABSTRACT FROM AUTHOR]

The natural healing of diabetic wounds is collectively impeded by multiple factors, including hyperglycemia, angiogenesis disorders, acute oxidative stress, and prolonged inflammation. Although considerable effort has been devoted to solving these problems, the treatment of diabetic wounds remains a major clinical obstacle. In light of this, we developed an innovative wound microenvironment self-adaptive hydrogel to promote the healing of diabetic wounds. The hydrogel was constructed by the crosslinking of 3-aminobenzeneboronic acid (PBA)-modified gelatin (Gel) and polyvinyl alcohol (PVA) by borate ester bonds, which showed high responsiveness to glucose. Meanwhile, the liposomes that encapsulated metformin, L -arginine, and L (+)-ascorbic acid were incorporated into the hydrogel framework. The hydrogel@lipo composite demonstrated shape adaptability, glucose responsiveness, and all-in-one capability, thereby effectively improving the intricate microenvironment of diabetic wounds. In vitro and in vivo experiments demonstrated the ability of hydrogel@lipo to mitigate oxidative stress, enhance angiogenesis, and attenuate inflammatory responses. Consequently, the hydrogel@lipo could accelerate diabetic wound healing (within two weeks). The cumulative findings strongly suggest the potential of hydrogel@lipo as a highly promising therapeutic dressing for advancing diabetic wound recovery. [ABSTRACT FROM AUTHOR]

The energy loss (Eloss) caused by inefficient charge transfer and large energy level offset at the buried interface can easily restrict the performance of p-i-n perovskite solar cells (PVSCs). In this study, the utilization of poly-TPD and P3CT-N as a dual-hole transporting layer (HTLs) was implemented in a sequential manner. This approach aimed to improve the charge transfer efficiency of the HTL and mitigate charge recombination at the interface between the HTL and PVK. The results showed that this strategy also could achieve more suitable energy levels, improve the quality of the perovskite film layer, and ultimately enhance the device's stability. IPVSCs employing the dual-HTLs approach exhibited the highest power conversion efficiency of 19.85%, and the open-circuit voltage increased to 1.09 V from 1.00 V. This study offers a straightforward and efficient approach to boost the device performance by minimizing Eloss and reducing the buried interfacial defects. The findings underscore the potential of employing a dual-HTL strategy as a promising pathway for further advancements in PVSCs. [ABSTRACT FROM AUTHOR]

Aqueous zinc-ion batteries (AZIBs) have been considered next-generation promising high-energy storage systems due to their cost-effectiveness and high safety. Nevertheless, the instability of the Zn metal anode posed by dendrite growth and volume changes presents a significant hurdle for AZIB commercialization. Here, we introduce a novel approach using a ZnIn2S4 nanoflower-coated carbon cloth (ZISG-CC) with hierarchical spatial channels to guide the nucleation and deposition of Zn, thereby constructing a stable Zn metal anode. The designed ZISG-CC electrode exhibits distinctive features, including an enlarged surface area, enhanced zincophilicity, and in situ formation of a ZnS/In interphase during the initial discharge process. These characteristics facilitate uniform Zn nucleation and the formation of a stable electrolyte–anode interface, enabling excellent reversibility of the Zn anode. As a result, the Zn/ZISG-CC anode demonstrates outstanding charge–discharge cycling performance in a symmetric cell, achieving 550 cycles at 10 mA cm−2/5 mA h cm−2 and 500 cycles at 20 mA cm−2/10 mA h cm−2. Furthermore, the Zn/ZISG-CC‖MnO2-graphene full cell exhibits a high capacity retention of 87.5% after 1000 cycles at 1 A g−1, along with favorable flexibility. This study introduces a novel strategy that utilizes the interaction between the electrode and electrolyte to stabilize the electrolyte–anode interface, enabling advanced Zn anodes in high-performance AZIBs. [ABSTRACT FROM AUTHOR]

Precise control of pH values at electrode interfaces enables the systematic investigation of pH-dependent processes by electrochemical means. In this work, we employed high-density complementary metal-oxide-semiconductor (CMOS) microelectrode arrays (MEAs) as miniaturized systems to induce and confine electrochemical reactions in areas corresponding to the pitch of single electrodes (17.5 μm). First, we present a strategy for generating localized pH patterns on the surface of the CMOS MEA with unprecedented spatial resolution. Leveraging the versatile routing capabilities of the switch matrix beneath the CMOS MEA, we created arbitrary combinations of anodic and cathodic electrodes and hence pH patterns. Moreover, we utilized the system to produce polymeric surface patterns by additive and subtractive methods. For additive patterning, we controlled the in situ formation of polydopamine at the microelectrode surface through oxidation of free dopamine above a threshold pH > 8.5. For subtractive patterning, we removed cell-adhesive poly- L -lysine from the electrode surface and backfilled the voids with antifouling polymers. Such polymers were chosen to provide a proof-of-concept application of controlling neuronal growth via electrochemically-induced patterns on the CMOS MEA surface. Importantly, our platform is compatible with commercially available high-density MEAs and requires no custom equipment, rendering the findings generalizable and accessible. [ABSTRACT FROM AUTHOR]

Despite the promising potential of zinc-ion batteries (ZIBs) for large-scale energy storage applications, their electrochemical performance is still hindered by zinc dendrites and side reactions. To address these challenges, the optimization of electrolyte composition emerges as a practical and straightforward approach to enhance the coulombic efficiency (CE) and Zn plating/stripping reversibility of ZIBs. Here, mannitol stands out due to its abundance of polar groups and cost-effectiveness, and an electrolyte mixture consisting of 0.02 M mannitol and 2 M ZnSO4 is demonstrated, resulting in an impressive improvement in Zn reversibility compared to the pure ZnSO4 electrolyte. Density functional theory (DFT) calculations and spectroscopic analysis shed light on mannitol's capability to reconstruct the solvation structure of Zn2+ and replace free water molecules. The inhibited dendrite growth on the zinc metal anode is further confirmed through in situ characterization. This work paves the way for the development of long-lifespan ZIBs. [ABSTRACT FROM AUTHOR]

A substantial number of works have focused on the identification and classification of high explosives and organic compounds based on nanosecond laser-induced plasma spectroscopy (LIPS), but the major spectral differences between different molecular solids are still not well understood. The objective of this work is to determine the spectral regions that are most discriminatory of each material using chemometrics. Five high explosives and five organics containing benzene rings are measured in an air environment using nanosecond LIPS. Six different regions of the spectrum are subsequently obtained using a six-channel spectrometer, and then k-means clustering analysis in two-dimensional principal component space is used for each wavelength band to reveal the greatest spectral disparities. It is speculated that more carbon atoms in the functional groups tend to participate in the formation of the C2 emission, while the carbon in the carbon ring tends to contribute more to the formation of the CN emission. Additionally, the quantitative correlations between C2 emission intensity, oxygen balance (OB), and aroma index are also clarified for the first time. Finally, well-performing classification models are established using well-chosen spectral features with a supervised quadratic discriminant classifier (QDC) and linear support vector machine (SVM) with both specificity and accuracy of above 99%. This work proposes that nanosecond LIPS can be used as a chemical probe to detect structural discrepancies among organic samples and thus distinguish them well. [ABSTRACT FROM AUTHOR]

Aggregation-induced emission (AIE) has been widely recognized as the key to solving the aggregation-caused quenching (ACQ) effect from the source. As the stacking states of AIE luminogens in the solid state are considered as the key of its performance, we constructed a series of novel biscarbazole-type molecules with different functional groups, and explored the effect of molecular stacking on the AIE phenomenon. With single crystal analysis and spectroscopic characterizations, we confirmed that the functional groups have significant effects on the molecular stacking in the solid state and AIE behaviors. Significantly, the synthetic 2,5-bis(3-(9H-carbazol-9-yl)propoxy)terephthalaldehyde (TPAK) molecule has been successfully used for the rapid detection of DNP (2,4-dinitrophenol) and Fe3+. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) phosphors play a key role in phosphor-converted NIR emitters, but to find broadband phosphors still remains a great challenge due to the lack of strategies for screening appropriate hosts. Herein, we report a broadband Sr6Sc2Al4O15:Cr3+ NIR phosphor by choosing a host that has crystallographic sites accommodated for both Ce3+ and Cr3+ simultaneously. The emission spectrum of Sr6Sc2Al4O15:Cr3+ covers the region of 600–1500 nm, having a maximum at 860 nm and a full width at half-maximum (FWHM) of 241 nm. A NIR pc-LED was fabricated by combining the Sr6Sc2Al4O15:Cr3+ phosphor with a blue LED, which can produce a NIR output power of 0.16 mW driven at 750 mA. The fabricated NIR emitter demonstrates a good suitability in night vision and non-destructive detection. [ABSTRACT FROM AUTHOR]

High-pressure structural, magnetic and electrical transport characteristics of CrBr3 were synthetically investigated using Raman scattering, electrical conductivity, high-resolution transmission electron microscopy (HRTEM) and first-principles theoretical calculations during compression and decompression under different hydrostatic conditions. Upon pressurization, CrBr3 underwent a second-order structural transition at 9.5 GPa, followed by the semiconductor-to-metal and magnetic switching at 25.9 GPa under non-hydrostatic conditions, whereas, an obvious pressure hysteresis of ∼3.0 GPa was detected in the occurrence of structural transitions and metallization under hydrostatic conditions due to the deviatoric stress. Upon decompression, the structural and electronic transitions of CrBr3 under different hydrostatic conditions were of good reversibility with a considerable pressure sluggishness of ∼5.0 GPa, which was corroborated well by the microstructural observation with HRTEM. Our systematic high-pressure investigation on CrBr3 not only reveals its underlying application in spintronic, magnetic and electronic devices but also advances the understanding of the physicochemical behaviors for 2D magnetic materials. [ABSTRACT FROM AUTHOR]

As a bifunctional oxygen electrocatalyst (oxygen reduction reaction (ORR) and oxygen evolution reaction (OER)), spinel copper cobaltite (CuCo2O4) is attracting significant research interest owing to the tailored Co, Cu electronic structure and ease of adjusting the electrochemically active area. However, its poor OER performance (>300 mV at 10 mA cm−2) limits its practical application for rechargeable zinc–air batteries. Therefore, we construct a CuCo2O4/NiFe LDH oxide/hydroxide interface to tune the properties of Ni, Fe and Co for enhancing OER activity and decreasing the charging overpotential of rechargeable zinc–air batteries. The obtained electrocatalysts show a low overpotential of 251 mV (10 mA cm−2), which is 91 mV lower than the overpotential (342 mV) of CuCo2O4. By in situ Raman, XPS and electrochemical analyses, we ascribe the enhanced OER activity to the increasing Ni/Fe oxidation state triggered by the charge transfer of Ni/Fe and Co, which prompts CuCo2O4/NiFe LDH to rapidly form an active surface layer. Benefiting from enhanced OER performance, zinc–air batteries with a CuCo2O4/NiFe LDH electrode display a high round-trip efficiency with a low voltage gap of ∼0.78 V (10 mA cm−2) due to the obvious decrease in the charging overpotential. These results suggest the importance of tuning the charge transfer on interfaces for designing high-efficiency electrocatalysts. [ABSTRACT FROM AUTHOR]

A one-step strategy is applied to partially quaternize the ligand of UiO-66-NH2, and the resultant UiO-66-N(CH3)3+ showed greatly improved photocatalytic performance for Cr(VI) reduction, with the apparent reaction rate constant k increasing by 8.3 times. This strategy could be used to effectively promote the performance of other MOFs-NH2, demonstrating general applicability. [ABSTRACT FROM AUTHOR]

The heat of detonation of energetic materials (EMs) is determined by the release of chemical energy, bond energies, and chemical structures and can be reflected by the variation of emission intensities in laser-induced breakdown spectroscopy (LIBS). Herein, we propose a new method based on laser-induced breakdown spectroscopy, combined with small-sample machine learning, to accurately determine the heat of detonation by consuming small-dose samples. A statistical correction strategy is applied to improve the spectral quality and extract spectral features including the emission peak intensity and emission shape correlation intensity. Thereby, a high-accuracy quantitative model based on the plasma spectra is developed to predict the heat of detonation with RMSEC = 0.0314 kJ g−1 and Rc2 = 0.99. Excellent model robustness is verified through three independent tests at different dates, which exhibit a strong predictive power with RMSET′ = 0.1776, 0.1217, and 0.1207 kJ g−1 and RT′2 = 0.98, 0.98, and 0.98, respectively. The elements of importance for analysis in the model further clarify that the quantitative diagnosis of the heat of detonation for EMs makes sense by LIBS. Therefore, this work can significantly facilitate the safe and fast determination of the heat of detonation of explosives in small-dosage samples. [ABSTRACT FROM AUTHOR]

Flexible supercapacitors (FSCs) are considered to be a promising electrochemical energy source for wearable electronic products. However, the absence of high-performance electrode materials and effective manufacturing techniques of devices hinder the volume production of FSCs. Here, a facile surface-etching method is investigated to prepare high-performance nickel hexacyanoferrate (NiHCF) electrode materials, and further, a screen-printing strategy is employed to realize high-volume production of FSCs. Compared with conventional NiHCF electrodes, the Na2Ni[Fe(CN)6]-based electrode with surface defect offers a specific capacity of 184 C g−1 (100 C g−1 for conventional NiHCF), and its capacity retention is 91% after 10 000 cycles. According to density functional theory (DFT) calculations, the excellent cycling stability can be attributed to the negligible structural distortion during the Na+ insertion/extraction process (∼6% volume change). Subsequently, symmetric FSCs are constructed by printing the NiHCF electrode materials on flexible PET substrates, displaying excellent areal capacitance of 7.3 mF cm−2 (0.1 mA cm−2) and energy density and power density of 0.65 μW h cm−2 and 0.4 mW cm−2, respectively. The surface-defect engineering provides a low-cost strategy to construct nickel hexacyanoferrate materials with outstanding electrochemical properties. The printed electronic techniques we have demonstrated for large-scale and low-cost printing FSCs applications are inspiring. [ABSTRACT FROM AUTHOR]

Since the first discovery of polyacetylene in the late 1970s, one-dimensional (1D) conjugated polymers have attracted immense research interest as a result of their high conductivity, wide and tunable band gap, and solution processability, making them extraordinary materials for the next-generation organic electronics, photovoltaics, and thermoelectrics. Recently, more research interest has been devoted to integrating the 1D conjugated polymers with organic tissues, e.g., implantable electrodes and electronic plants, as their excellent biofunctions and biocompatibilities are demonstrated. However, to achieve optimal material designs for the 1D conjugated polymers in practical applications, it is essential to understand their fundamental charge transport mechanisms. The current reviews are mainly focused on the functional properties and applications of the conjugated polymers while the theoretical models for charge transport and their correlations with the experimental observations are barely discussed systematically. In this review article, we try to elucidate the nature of charge carriers by taking the total footprints of the research and development in conjugated polymers for consideration, from molecular orbitals to thermally activated conductivity. The electronic structures and mathematical description of the charge carriers, i.e., solitons, polarons, and bipolarons, are discussed and analyzed based on the frontier molecular orbital theory, non-interacting model, Su–Schrieffer–Heeger model, density functional theory, and Holstein-based models. The predicted electronic structures for the charge carriers are model-dependent which can be either weakly or strongly correlated with the Coulomb interactions in the valence and conduction bands. Origins of the optical signatures of the charge carriers, e.g., polarons and bipolarons, in the visible, near infrared, and mid infrared ranges are described and discussed, which may provide semi-quantitative information on the conjugation length and delocalization of the charge carriers. Experimental observations of the spectroscopic characteristics of the charge carriers and their correlations with the molecular configuration, conductivity, crystallinity, and composition of the conjugated polymers are carefully reviewed and compared based on doping induced dopant–host interactions. The transport mechanism of the charge carriers can be described two-dimensionally in the microscale and probed by analyzing the thermoelectric properties of the conjugated polymers and modelling the thermally activated conductivity as a function of the thermopower at the device scale. [ABSTRACT FROM AUTHOR]

An amine and bis(phenylsulfonyl)methane co-catalyzed hydrogen–deuterium exchange (HDE) method via a Michael-retro-Michael pathway for site-selective introduction of deuterium at the α-position of enals using D2O as a deuterium source has been achieved. The mild, operationally simple protocol allows for high yielding and high level deuterium incorporation (up to 99%) for structurally diverse aromatic-derived enals and dienals. [ABSTRACT FROM AUTHOR]

In general, high-accuracy quantitative analysis of material components based on laser induced breakdown spectra requires large sample sizes for accurate modeling. However, in most cases, there are no abundant standard samples. Herein, small sample size (less than 20 standard samples) machine learning based on LIBS is utilized to realize high-accuracy quantitative analysis of coal. The algorithm is implemented through specific data extraction and data resampling. Partial spectra of each sample are extracted to form a batch of training data for establishing a prediction model based on the principal component analysis combined with partial least squares method (PCA-PLS). Repeatedly stochastic data are extracted from the spectra of the samples to form abundant batches of training data sets, and thus the most representative dataset is discovered in the training processes. The model trained by the new algorithm via 10–15 samples has a comparable performance to the model trained by the traditional method via 60–80 samples. With a training sample size of 15, the ARE of carbon prediction is less than 4% in the new prediction model, indicating that the proposed model has better generalization and higher prediction accuracy for small-sample-size machine learning. It will greatly improve the universality of the LIBS technology for fast elemental detection. [ABSTRACT FROM AUTHOR]

Lithium is thought to be an excellent anode material for next-generation Li metal batteries (LMBs). However, some problems with lithium anodes often lead to serious safety concerns and catastrophic failures due to the huge volume change, Li dendritic growth, and related side reactions. Therefore, in order to manufacture stable rechargeable batteries, the abovementioned serious problems must be effectively solved. In this paper, a three-dimensional N,P-doped silicon-containing lithium anode is designed and prepared by in situ metallurgy using low-cost Si3N4. The 3D stable composite anode (DLi/LiSix CA) was prepared by adding a small amount of Si3N4 to molten lithium to form N-doped silicon-containing lithium metal which was supported on a polyaniline modified carbon cloth (PMCC). The results show that the DLi/LiSix CA not only has high Li affinity but can also effectively inhibit lithium nucleation and lithium dendritic growth, so as to maintain good structural stability in the process of Li plating/stripping. The new lithium metal anode based on doping and 3D carbon cloth shows good cycling stability and low polarizability in both symmetrical and full cells. [ABSTRACT FROM AUTHOR]

Developing highly efficient small molecule hole-transporting materials (HTMs) to improve the performance of devices is one of the hot topics in the progress of perovskite solar cells (PSCs). In this work, a series of molecules are designed by utilizing benzocyclobutadiene (C1), bicyclo[6.2.0]decapentaene (C2), naphthalene (C3), biphenylene (C4), fluorene (C5), and azulene (C6) as the π-cores, and p-methoxydiphenylamine (R1), p-methoxytriphenylamine (R2) and p-methoxydiphenylamine-substituted carbazole (R3) as the peripheral groups. For isolated molecules, frontier molecule orbitals, absorption and emission spectra, Stokes shift, stability, solubility, and hole mobility are assessed by density functional theory calculations along with the Marcus theory of electron transfer. The molecules adsorbed on the surface of CH3NH3PbI3 are used to simulate the interfacial properties between HTMs and perovskites. Our results indicate that varying the central bridge and the terminal groups has a remarkable influence on the properties. The designed R2-Cn (n = 3, 4, 5) have deeper HOMO levels, stronger absorption in the UV region, and larger Stokes shift than Spiro-OMeTAD. They also possess good solubility, stability, and hole mobility. The proper alignment of interfacial energy levels ensures the transfer of holes from CH3NH3PbI3 to the studied molecules and blocks the backflow of electrons simultaneously. Significant charge redistributions around the interfacial region benefit the separation and transfer photogenerated electron–hole pairs. The results of the present study can be further employed in the process of synthesizing new HTMs with promising features. [ABSTRACT FROM AUTHOR]

A series of structural, vibrational and electrical transport behaviors for HfS2 were systematically investigated by Raman spectroscopy, electrical conductivity, high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM) in conjunction with first-principles theoretical calculations in the processes of compression and decompression under different hydrostatic environments. High-pressure Raman scattering and electrical conductivity results revealed that HfS2 underwent two structural phase transitions and metallization at 8.0, 15.2 and 20.5 GPa under non-hydrostatic conditions. The first structural transition was characterized by the appearance of the M1 and M2 Raman peaks and the inflection point in the pressure-dependent electrical conductivity. The second structural transition was identified from the disappearance of the Eg, M1 and M2 Raman peaks, the emergence of the M3–M6 Raman peaks, and the discontinuities in the pressure coefficient of the A1g mode and electrical conductivity. As the pressure increased to 20.5 GPa, HfS2 underwent a metallization transition, which was attributed to the closure of the bandgap energy obtained from first-principles theoretical calculations. Under hydrostatic conditions, two structural transformations and metallization of HfS2 occurred at relatively high pressures of 8.2, 17.2 and 23.1 GPa due to different deviatoric stress. Upon decompression, the phase transition was revealed to be reversible under different hydrostatic environments, which was verified by the HRTEM and AFM results. Our acquired results of the crystalline and electronic structures of HfS2 facilitate the understanding of the high-pressure characterization of other HfX2 compounds (X = Se and Te) under different hydrostatic environments. [ABSTRACT FROM AUTHOR]

Herein, we report the selective synthesis, characterization, and photophysical properties of two novel chiral carbon macrocycles. Non-planar (S)-2,2′-bis(methoxymethoxy)-1,1′-binaphthalene was introduced into the scaffold of oligo-paraphenylenes to achieve the chirality in these macrocycles. Their photophysical properties were investigated by steady-state and time-resolved spectroscopies, as well as circular dichroism and circularly polarized luminescence spectroscopies. We demonstrate that the emission maxima of the chiral macrocycles are redshifted compared to chiral binaphthyl units and that macrocycles show chiroptical properties (‖glum‖ > 1.0 × 10−3). [ABSTRACT FROM AUTHOR]

Two-dimensional polymers functionalized with controllable density of carboxyl groups were constructed with the Langmuir–Blodgett method. Mineralization of calcium phosphate shows significantly different characteristics on these films, which clearly indicates that the density of carboxy groups plays a determining role in controlling the nucleation and orientated growth of calcium phosphate. [ABSTRACT FROM AUTHOR]

In this work, an electrogenerated chemiluminescence (ECL) sensor was fabricated to detect silver ions based on the competitive interaction between luminol, silver ions and cucurbit[6]uril (Q[6]). The Q[6]-modified electrode (Q[6]/GCE) exhibited the best electrochemical response among various Q[n]-modified electrodes and was selected for ECL measurements. Strong anodic luminol ECL was obtained at the Q[6]/GCE due to the interaction between luminol, oxygen, and Q[6]. In the presence of Ag+, the strong coordination interaction between Ag+ and Q[6] could decrease the concentration of luminol and oxygen on the electrode surface, resulting in a decreased ECL signal. The variation of the ECL intensity was linearly correlated with the Ag+ concentration. Therefore, an ECL sensor for the quantitative detection of Ag+ was proposed. Under the optimal conditions, Ag+ can be detected in the range of 10 nM to 5 μM, and the detection limit was calculated as 8.2 nM (3σ). The proposed ECL sensor shows outstanding specificity and accuracy, indicating that cucurbit[n]urils have great potential applications in the detection of metal ions. [ABSTRACT FROM AUTHOR]

This study describes a cascade method for the synthesis of β-aminoketones through the reductive hydroamination of alkynes under very mild metal-free conditions. It allows for the rapid conversion of ynones and amines into corresponding β-aminoketones with a broad substrate scope and diverse functionalities. This straightforward and easy-to-handle reaction process can be successfully applied for the synthesis of Proroxan and Propipocaine, offering a potential option for the synthesis of drug molecules with the β-aminoketone skeleton. [ABSTRACT FROM AUTHOR]

Regulating surface oxidation state and understanding how it governs the reactivity and durability of electrocatalysts is a key problem for designing promising OER electrocatalysts. Here, a "natural cooling" method is reported for tuning the oxidation state of NiFe LDH. The optimal NiFe LDH electrocatalyst exhibits enhanced OER activity, such as low overpotential (231 mV at 20 mA cm−2), high TOFs (0.008–0.029 s−1 at 250–280 mV) and superior stability at high current densities (100 and 220 mA cm−2). XPS, Raman, and electrochemical analyses and theoretical calculations reveal that the Ni and Fe ions with higher oxidation state can greatly enhance OER activity. Our work shows that the oxidation states of active sites play a key role in promoting the OER activity of NiFe LDHs. As a non-composited strategy, the "natural-cooling" method can be employed to guide the designing of top electrocatalysts with favorable surface oxidation states. [ABSTRACT FROM AUTHOR]

A host–guest system is constructed using a guest containing two selenium atoms. The selenium atoms can increase the spin–orbit coupling constant and the conjugation degree, thereby increasing the emission wavelength, and making the materials show only phosphorescence emission. [ABSTRACT FROM AUTHOR]

In the past few years, cellulose nanomaterials obtained from lignocellulose have attracted extensive attention as functional nanomaterials with excellent properties and great application potential in a variety of high-tech fields. However, the preparation of cellulose nanomaterials is facing several challenges such as the large amount of energy consumption, chemical recovery issues, and complicated purification and pretreatment processes, which have limited their large-scale application. Fortunately, lignin-containing cellulose nanomaterials have emerged as a new type of cellulose nanomaterial because of the low energy and chemical consumption, easy preparation process, and special properties. This review showcases a comprehensive overview of research status on the preparation and application of lignin-containing cellulose nanomaterials, focusing on recently developed green and low-cost preparation processes. The potential applications of lignin-containing cellulose nanomaterials as building blocks and reinforcing agents for the design of various advanced materials are summarized as well. Finally, the current challenges and future directions for the preparation and application of lignin-containing cellulose nanomaterials are provided. [ABSTRACT FROM AUTHOR]

Since lead has a very high absorption coefficient (μ), the radiations from within the bulk material do not penetrate the layers. While oxygen and water (O2 and H2O) in the environment react with lead forming the oxide of lead, the radiation protection performance will be degradation. In this study, density functional theory was used to study the mechanical and dielectric properties of lead oxides (α-PbO, β-PbO, CsCl–PbO, α-PbO2, and β-PbO2). Young's modulus, bulk modulus and shear modulus, Poisson's ratio and many other parameters under strain in the range of −20% to +20% were calculated. Particularly for lead oxides, the Pb 6s lone-pair electron states were also discussed, and their influence on the mechanical and dielectric properties was unveiled in detail. Surprisingly, it was found that the electric dipoles formed by lone-pair lobes contributed only slightly to the strain synergy effect, whereas the concomitant ionic displacements and lattice distortions were prominently favorable for mechanical and optical behaviors. Indeed, it was found that the strain synergy effects played an important role in the mechanical and optical behaviors of lead oxides, especially apparent for β-PbO. This study provides a simple yet straightforward way to demonstrate the mechanisms of strain synergy effects in the high temperature phase oxide of lead, which can be applied to the study of the same mechanism in other relevant materials. [ABSTRACT FROM AUTHOR]

To overcome the limitations of both LDHs and MXenes, we develop a self-sacrifice template strategy using a zeolite imidazolate framework-67 (ZIF-67) to derive Co-LDH anchored on an MXene conductive substrate (Co-LDH/MXene). In this process, ZIF-67 grows on the MXene nanosheets, then spontaneously transforms into Co-LDH/MXene in aqueous solution at room temperature. As the LIB anode, it shows a reversible capacity of 854.9 and 398.0 mAh g−1 at 0.1 and 1 A g−1, respectively. This work proposes a feasible synthesis method for the in situ construction of a Co-LDH/MXene hybrid, which may be suitable for other MXenes. [ABSTRACT FROM AUTHOR]

Infectious diseases caused by bacteria, viruses, and fungi and their global spread pose a great threat to human health. The 2019 World Health Organization report predicted that infection-related mortality will be similar to cancer mortality by 2050. Particularly, the global cumulative numbers of the recent outbreak of coronavirus disease (COVID-19) have reached 110.7 million cases and over 2.4 million deaths as of February 23, 2021. Moreover, the crisis of these infectious diseases exposes the many problems of traditional diagnosis, treatment, and prevention, such as time-consuming and unselective detection methods, the emergence of drug-resistant bacteria, serious side effects, and poor drug delivery. There is an urgent need for rapid and sensitive diagnosis as well as high efficacy and low toxicity treatments. The emergence of nanomedicine has provided a promising strategy to greatly enhance detection methods and drug treatment efficacy. Owing to their unique optical, magnetic, and electrical properties, nanoparticles (NPs) have great potential for the fast and selective detection of bacteria, viruses, and fungi. NPs exhibit remarkable antibacterial activity by releasing reactive oxygen species and metal ions, exerting photothermal effects, and causing destruction of the cell membrane. Nano-based delivery systems can further improve drug permeability, reduce the side effects of drugs, and prolong systemic circulation time and drug half-life. Moreover, effective drugs against COVID-19 are still lacking. Recently, nanomedicine has shown great potential to accelerate the development of safe and novel anti-COVID-19 drugs. This article reviews the fundamental mechanisms and the latest developments in the treatment and diagnosis of bacteria, viruses, and fungi and discusses the challenges and perspectives in the application of nanomedicine. [ABSTRACT FROM AUTHOR]

Four isoquinolinone–arylidenehydrazine derivatives with different aryl groups, such as benzene (BHIQ), naphthalene (NHIQ), anthracene (AHIQ), and triphenylamine (TPHIQ), have been designed and synthesized. These compounds exhibit solid-state fluorescence with emission wavelengths covering the whole visible-light region. Most of them have two crystalline structures with different fluorescence colours. Interestingly, although all the compounds adopt a keto-form structure in solvents, keto- and enol-form crystalline structures are obtained separately for BHIQ, while the two polymorphs of NHIQ and AHIQ exist in the keto-form and the enol-form, respectively. Moreover, the difference in the emissions of the NHIQ polymorphs is attributed to different stacking arrangements, while that of the AHIQ polymorphs is ascribed to different molecular conformations. These results indicate that crystalline structures with different emissions can be obtained via polymorphism and keto–enol tautomerism, respectively. Furthermore, some crystalline structures of these compounds exhibit obvious mechanofluorochromic activities due to the crystalline-to-amorphous transition and solid-state acidochromic properties owing to the change in intramolecular charge transfer caused by protonation. This work provides a strategy for the development of solid-state fluorescent stimulus-responsive materials with keto–enol tautomerism. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) has been extensively considered as a clean and renewable energy carrier and the most promising alternative to conventional fossil fuels for future energy supplies due to its ultrahigh energy density and zero pollution. Selective "on–off" switches for on-demand liquid-phase H2 evolution are crucial and challenging for efficient utilization and production of H2. At present, the on-demand liquid-phase H2 evolutions are mainly controlled by five types of switches, namely catalyst-transfer switch, phase-transfer switch, pH-adjusting switch, temperature-adjusting switch, and light-adjusting switch. In this minireview, an overview of these "on–off" approaches with a particular emphasis on the recent advances in mechanism exploration and applications has been presented. Finally, we provide the future research directions and perspectives for overcoming the challenges in the commercialization of a promising approach. [ABSTRACT FROM AUTHOR]