Latest ArticlesNa3V2(PO4)3 is a very prospective sodium-ion batteries (SIBs) electrode material owing to its NASICON structure and high reversible capacity. Conversely, on account of its intrinsic poor electronic conductivity, Na3V2(PO4)3 electrode materials confront with some significant limitations like poor cycle and rate performance which inhibit their practical applications in the energy fields. Herein, a simple two-step method has been implemented for the successful preparation of carbon-coated Na3V2(PO4)3 materials. As synthesized sample shows a remarkable electrochemical performance of 124.1 mAh/g at 0.1 C (1 C = 117.6 mA/g), retaining 78.5 mAh/g under a high rate of 200 C and a long cycle-performance (retaining 80.7 mAh/g even after 10000 cycles at 20 C), outperforming the most advanced cathode materials as reported in literatures.
Material stability is always the key factor for applied materials especially the working environment that requires higher temperature sensitivity or temperature fluctuation range. In which, the stimulus-response perovskite materials are just sensitive to stability to ensure the accuracy and stability of the signals, in the applied devices of batteries and memory storage devices and so on. However, it is still a tremendous challenge to improve the stability of perovskite materials, and maintain reliability in the devices. Here, a novel ABX2X'1 (X-site doping in an ABX3) compound [CEMP]-[CdBr2(SCN)] (1, CEMP = 1-(2-chloro-ethyl)-1-methyl-piperidine) with remarkable high-temperature reversible dielectric switching behavior was proposed. The strategy of [SCN]− doping in perovskite for improving the stability was successfully achieved. Meanwhile, the steric hindrance is increased while the energy barrier is also increased by replacing hydrogen with flexible groups, which leads to a high-temperature reversible phase transition. The new finding provides a new direction to enrich new applications and design ideas of perovskite materials. Especially the X-site strategy of doping or substitution in the ABX3, it will promote ingenious and perfect experimental results in material synthesis and performance improvement by chemistry disciplines.
In this paper, a hydrothermal approach is utilized for the first time in integrating graphene oxide (GO), acetic acid (HAc) and nickel foam to prepare hydrogenated graphene (HG). There are two primary aims of this study: one is to ascertain the structure of the as-prepared HG, and the other one is to investigate the ferromagnetism of the HG. Under hydrothermal conditions, GO was reduced and hydrogenated by HAc, while the nickel foam served as a catalyst. This work provides a novel and facile route for the synthesis of hydrogenated graphene, which may lead to the application of hydrogenated graphene in spin electronic devices.
Ultrabroad spectral absorption is required for semiconductor photocatalysts utilized for solar-to-chemical energy conversion. The light response range can be extended by element doping, but the photocatalytic performance is generally not enhanced correspondingly. Here we present a solid alkali activation strategy to synthesize near-infrared (NIR) light-activated carbon-doped polymeric carbon nitride (A-cPCN) by combining the copolymerization of melamine and 1, 3, 5-trimesic acid. The prepared A-cPCN is highly crystalline with a narrowed bandgap and enhanced efficiency in the separation of photogenerated electrons and holes. Under irradiation with NIR light (780 nm ≥ λ ≥ 700 nm), A-cPCN shows an excellent photocatalytic activity for H2 generation from water with rate of 165 µmol g−1 h−1, and the photo-redox activity for H2O2 production (109 µmol g−1 h−1) from H2O and O2, whereas no observed photocatalytic activity over pure PCN. The NIR photocatalytic activity is due to carbon doping, which leads to the formation of an interband level, and the alkali activation that achieved shrinking the transfer distance of photocarriers. The current synergistic strategy may open insights to fabricate other carbon-nitrogen-based photocatalysts for enhanced solar energy capture and conversion.
Functional dicyclophanes with various substituents (e.g., NO2, Br, OCH3 and OH) were synthesized via one-pot SN2 reaction. Dicyclophanes can form nanospheres via the head-to-tail self-assembly between the cavities and the TPE units to exhibit aggregation-induced emission (AIE) in aqueous solution. These AIE-active nanospheres with cationic feature exhibited selective recognition with fluorescence response for anionic ATP via electrostatic interactions and hydrophobic effects in water.
Ozone (O3) plays essential roles in stratosphere and helps reduce the amount of harmful ultraviolet arriving the Earth's surface. However, O3 is also a strong oxidant and causes troubles to human health in troposphere, especially in the confined space, such as indoor environment. Recently, O3 abatement materials have become research hotspots due to the urgent environmental demands. Catalysis is a facile strategy that can eliminate indoor airborne O3 efficiently and economically. Thus, this review summarizes the recent progresses of O3 decomposition catalysts. The catalysts covered here are categorized as follows: zeolite, metal organic frameworks (MOFs), metal oxides, noble metals. Manganese-based catalysts display higher efficiency and are mainly discussed. Generally, the active sites of O3 decomposition catalysts are described as Lewis acid sites (e.g., zeolite), metal sites (e.g., MOFs), oxygen vacancy sites (e.g., MnO2) in the previous work. In this review, we ascribe all the active sites to unsaturated metal sites and their Lewis acidity. Possible evidence from the experimental and theoretical perspectives are proposed. Furthermore, the strategy to circumvent deactivation caused by peroxides (O22-) accumulation and water molecular competition are also elaborated. Finally, perspective is presented on the challenges and opportunities of exploring existing and new O3 decomposition catalysts.
Biochar (BC) are widely used as highly efficient adsorbents to alleviate aromatics-based contaminants due to their ease of preparation, wide availability, and high sustainability. The surface properties of BCs usually vary greatly due to their complex chemical constituents and different preparation processes and are reflected in the values of parameters such as the specific surface area (SSA), pore volume/size, and surface functional groups (SFGs). The effects of SSA and pore volume/size on the adsorption of aromatics have been widely reported. However, the corresponding mechanisms of BC SFGs towards aromatics adsorption remains unclear as the compositions of the SFGs are usually complex and hard to determine. To address in this gap in the literature, this review introduces a new perspective on the adsorption mechanisms of aromatics. Through collecting previously-reported results, the parameters logP (logarithm of the Kow), polar surface area, and the positive/negative charges were carefully calculated using ChemDraw 3D, which allowed the hydrophobicity/hydrophilicity properties, electron donor-acceptor interactions, H-bonding, and electrostatic interactions between SFGs and aromatics-based contaminates to be inferred intuitively. These predictions were consistent with the reported results and showed that tailor-made BCs can be designed according to the molecular weights, chemical structures, and polarities of the target aromatics. Overall, this review provides new insight into predicting the physicochemical properties of BCs through revealing the relationship between SFGs and adsorbates, which may provide useful guidance for the preparing of highly-efficient, functional BCs for the adsorption of aromatics.
The widespread applications of aggregation-induced emission luminogens (AIEgens) inspire the creation of AIEgens with novel structures and functionalities. In this work, we focused on the direct and efficient synthesis of a new type of AIEgens, imidazo[1, 5-a]pyridicne derivatives, via iodine mediated cascade oxidative Csp2–H or Csp–H amination route from phenylacetylene or styrenes under mild conditions. The resulted compounds showed excellent AIE characteristics with tunable maximum emissions, attractive bioimaging performance, and potential anti-inflammatory activity, which exert broad application prospects in material, biology, medicine, and other relevant areas.
Recently discovered bismuth oxychalcogenide (Bi2O2Se) has aroused great interest due to its ultrahigh carrier mobility, tunable band gap and good environmental stability, making it a promising candidate for high-performance electronics and optoelectronics. Their synthesis by colloidal approaches represents a cost-effective alternative to well-established chemical vapor deposition methods, and the resulting electronic-grade inks are important for large-area printed or wearable electronics. However, it is still challenging to control the colloidal growth of Bi2O2Se nanosheets in solution in addition to their assembly into high-performance thin films. Here, we report a two-step colloidal synthesis of Bi2O2Se nanosheets by separating the seeding and growth steps, thereby achieving controllable production of nanosheets with a lateral size of 1.4 μm and a thickness of 10 nm at optimized reaction conditions. These Bi2O2Se nanosheets are electrostatically assembled into large-area thin films, from which a photodetector is fabricated with a responsivity of 6.1 A/W and a short response time of 368 μs under the 520-nm laser illumination. The device exhibits fast response to modulations as high as 100 kHz, along with a −3 dB bandwidth of 1 kHz. This work provides an important understanding of the controlled colloidal synthesis of Bi2O2Se nanosheets, and demonstrates their potential applications in fast photodetectors.
In this research, a novel bird nest-like zinc oxide (BN-ZnO) nanostructures were prepared by a simple solvothermal method. A sensitive electrochemical glucose biosensor was for the first time developed based on the immobilization of glucose oxidase (GOx) on nanostructured BN-ZnO modified electrode. The BN-ZnO nanostructure and the resultant biosensor were characterized by scanning electron microscope, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and electrochemical impedance spectroscopy. BN-ZnO nanostructures have large specific surface area and can load large amounts of GOx molecules. Meanwhile, BN-ZnO provides an excellent microenvironment to retain the native bioactivity of enzymes and to promote direct electron transfer between GOx and electrode surface. The proposed biosensor shows a wide linear range of 0.005–1.6 mmol/L, high sensitivity of 15.6 mAL mol−1 cm−2 with a low detection limit of 0.004 mmol/L. The resulting biosensor also shows excellent selectivity, acceptable stability and reproducibility, and can be successfully applied in the detection of glucose in human serum samples at −0.37V.