Latest ArticlesThe 1D microwires based on π-extended azaBODIPY were successfully prepared and characterized for the first time. The bisphenanthrene-fused azaBPP-12C with four hydrophobic chains was prepared through de novo synthesis method involving the Suzuki reaction and subsequent oxidative ring-fused coupling. The microwires and aggregation behavior were studied using SEM, XRD and absorption spectroscopy. Finally, an H-type aggregation was confirmed in the solution process.
The development of novel anode materials, with superior rate capability, is of utmost significance for the successful realization of sodium-ion batteries (SIBs). Herein, we present a nanocomposite of Nb2O5 and reduced graphene oxide (rGO) by using hydrothermal-assisted microemulsion route. The water-in-oil microemulsion formed nanoreactors, which restrained the particle size of Nb2O5 and shortened the diffusion length of ions. Moreover, the rGO network prevented agglomeration of Nb2O5 nanoparticles and improved electronic conductivity. Consequently, Nb2O5@rGO nanocomposite is employed as anode material in SIBs, delivering a capacity of 195 mAh/g after 200 charge/discharge cycles at 0.2 A/g. Moreover, owing to conductive rGO network, the Nb2O5@rGO electrode rendered a specific capacity of 76 mAh/g at high current density of 10 A/g and maintained 98 mAh/g after 1000 charge/discharge cycles at 2 A/g. The Nb2O5@rGO electrode material prepared by microemulsion method shows promising possibilities for application of SIBs.
Charge transfer via electron hopping from an electron donor (D) to an acceptor (A) in nanoscale, plays a crucial role in optoelectronic materials, such as organic light-emitting diodes (OLEDs) and organic photovoltaic cells (OPVs). Here, we propose a strategy for binding D/A units in space, where intramolecular charge-transfer can take place. The resulted material DM-Me-B is able to give bright emission in this molecular architecture because of the good control of D/A interaction and conformational rigidity. Moreover, DM-Me-B presents small singlet-triplet splitting energy, enabling thermally activated delayed fluorescence. Therefore, the DM-Me-B exhibits ~20% maximum external quantum efficiency and low efficiency roll-off at 1000cd/m2, certifying an effective strategy in controlling D/A blocks through space.
Catalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) have garnered great attention as the key character in metal-air batteries. Herein, we developed a superior nonprecious bifunctional oxygen electrocatalyst, fabricated through spatial confinement of Fe/Fe3C nanocrystals in pyridinic N and Fe-Nx rich carbon nanotubes (Fe/Fe3C-N-CNTs). During ORR, the resultant electrocatalyst exhibits positive onset potential of 1.0 V (vs. RHE), large half-wave potentials of 0.88 V (vs. RHE), which is more positive than Pt/C (0.98 V and 0.83 V, respectively). Remarkably, Fe/Fe3C-N-CNTs exhibits outstanding durability and great methanol tolerance, exceeding Pt/C and most reported nonprecious metal-based oxygen reduction electrocatalysts. Moreover, Fe/Fe3C-N-CNTs show a markedly low potential at j =10 mA/cm2, small Tafel slopes and extremely high stability for OER. Impressively, the Fe/Fe3C-N-CNTs-based Zn-air batteries demonstrate high power density of 183 mW/cm2 and robust charge/discharge stability. It is revealed that the spatial confinement effect can impede the aggregation and corrosion of Fe/Fe3C nanocrystals. Meanwhile, Fe/Fe3C and Fe-Nx play synergistic effect on boosting the ORR/OER activity, which provides an important guideline for construction of inexpensive nonprecious metal-carbon hybrid nanomaterials.
In this work, various Co3O4-ZSM-5 catalysts were prepared by the microwave hydrothermal method (MH-Co3O4@ZSM-5), dynamic hydrothermal method (DH-Co3O4@ZSM-5), and conventional hydrothermal method (CH-Co3O4/ZSM-5). Their catalytic oxidation of dichloromethane (DCM) was analyzed. Detailed characterizations such as X-ray diffractometer (XRD), scanning microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), H2 temperature-programmed reduction (H2-TPR), temperature-programmed desorption of O2 (O2-TPD), temperature-programmed desorption of NH3 (NH3-TPD), diffuse reflectance infrared Fourier-transform spectra with NH3 molecules (NH3-DRIFT), and temperature-programmed surface reaction (TPSR) were performed. Results showed that with the assistance of microwave, MH-Co3O4@ZSM-5 formed a uniform core-shell structure, while the other two samples did not. MH-Co3O4@ZSM-5 possessed rich surface adsorbed oxygen species, higher ratio of Co3+/Co2+, strong acidity, high reducibility, and oxygen mobility among the three Co3O4-ZSM-5 catalysts, which was beneficial for the improvement of DCM oxidation. In the oxidation of dichloromethane, MH-Co3O4@ZSM-5 presented the best activity and mineralization, which was consistent with the characterizations results. Meanwhile, according to the TPSR test, HCl or Cl2 removal from the catalyst surface was also promoted in MH-Co3O4@ZSM-5 by their abundant Brønsted acid sites and the promotion of Deacon reaction by Co3O4 or the synergistic effect of Co3O4 and ZSM-5. According to the results of in situ DRIFT studies, a possible reaction pathway of DCM oxidation was proposed over the MH-Co3O4@ZSM-5 catalysts.
MoS2 has emerged for catalyzing the hydrogen evolution reaction. Various notable strategies have been developed to downsize the MoS2 particles and expose more active edges. However, the restacking issue, which reduces the exposure degree, has rarely been taken into account. Herein, we report on a facile proton-induced fast hydrothermal approach to produce size-controllable MoS2 nanocatalysts and demonstrate that along the varying of sheet sizes, there is a trade-off between the intrinsic catalytic activity (mainly determined by the unsaturated sulfur on the sheet edges) and the active edge accessibility (influenced by the assembly structure). The size-optimized catalyst delivers a high performance of a low overpotential of ~200 mV at 10 mA/cm2, a Tafel slope of 46.3 mV/dec, and a stable working state, which is comparable to the recent notable works. Our findings will provide a pathway for its large-scale application and enhance the water electrolysis performance.
A simple and efficient visible-light-induced photoredox-catalyzed diarylation of N-methacryloyl-2-arylbenzoimidazoles with aryl diazonium salts was developed. The reaction provides a convenient access to a variety of benzimidazoisoquinolinones through the construction of two CC bonds in one step under mild reaction conditions.
A template-free carbonization-activation route is developed to fabricate sub-nanopore-containing porous carbon by using a novel polypyrrole (PPy) hydrogel as a precursor. This design of PPy hydrogel precursor containing molecular-scale grids (diameter ~2.0 nm) allows for homogeneous N, O-codoping into the porous carbon scaffold during the pyrolysis process. A subsequent activation step produces activated porous carbons (APCs) with tailored pore structures, which renders the APCs abundant sub-nanopores on their surface to increase the specific capacitance as extra capacitance sites. Coupled with large specific surface area and abundant heteroatoms, the optimized APC4/1 displays excellent specific capacitance of 379 F/g for liquid-state supercapacitor and 230 F/g for solid-state supercapacitor. The solid-state supercapacitor shows a high energy density of 22.99 Wh/kg at power density of 420 W/kg, which is higher than most reported porous carbon materials and satisfy the urgent requirements of elementary power source for electric vehicles. Moreover, this method can be easily modified to fabricate sub-nanopore-containing porous carbons with preferred structures and compositions for many applications.
Lithium sulfur batteries with high energy density are thought to be the most potential energy storage technology that can be commercialized. However, the shuttle effect of polysulfides deteriorates its electrochemical performance. Herein, a novel Co9S8 nanostructure derived from metal organic framework material (MOF) was explored by simple liquid phase reaction and heat vulcanization of 2-methylimidazole and Co(NO3)2·6H2O on the surface of the original PP separator. The Co9S8 nano-flower cluster array wall was vertically and closely arranged with the thickness of 200 nm, and the polysulfide can be adsorbed by its physical and chemical action to slow down the "shuttle effect". It is found that the cell with the modified separator can achieve an ideal discharge capacity of about 600 mAh/g at 1 C. The specific capacity is maintained at 500 mAh/g after 200 cycles, with only 0.11% of capacity decay per cycle. It provides a new way for the utilization of MOF material derivatives to modify the separator in order to improve the electrochemical performance of lithium-sulfur batteries.
Three novel polycyclic polyprenyled acylphloroglucinols, Hyperscabins A-C, were obtained from the aerial parts of Hypericum scabrum. They featured an unprecedented 5, 5-spiroketal subunit with the loss of C-2' carbonyl in the phloroglucinol ring. Their structures were characterized by extensive spectroscopic analyses, NMR calculations with DP4+ analysis, calculated electronic circular dichroism (ECD) spectra and the application of modified Mosher's methods. In the assay of [3H]-5-HT and [3H]-NE reuptake inhibition, compounds 1 and 2 showed good inhibitory activity (81.8% and 83.2%) in 10 μmol/L. In addition, compound 1 significantly increased cell viability in the experiment of oxygen and glucose deprivation/deoxygenation.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
