Redox flow batteries (RFBs) usually contain aqueous or organic electrolytes. The aim of this communication is to explore the suitability of room temperature ionic liquids (RTILs) as solvents for RFBs containing metal complexes. Towards this aim, the electrochemistry of the metal acetylacetonate (acac) complexes Mn(acac)3, Cr(acac)3, and V(acac)3 was studied in imidazolium-based RTILs. The V2+/V3+, V3+/V4+, and V4+/V5+ redox couples are quasi-reversible in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [C2C1Im][N(Tf2)]. The Mn(acac)3 and Cr(acac)3 voltammetry, on the other hand, is irreversible in [C2C1Im][N(Tf2)] at glassy carbon (GC) but the rate of the Mn2+/Mn3+ reaction increases if Au electrodes are used. Charge–discharge measurements show that a coulombic efficiency of 72% is achievable using a V(acac)3/[C2C1Im][N(Tf2)]/GC cell. 相似文献
The production of ligno-cellulosic biomass-based composites requires the development of new methodologies to evaluate the reinforcement potential of a given biomass, such as miscanthus studied in the work. Miscanthus stems from thirteen genotypes were broken into elongated fragments and mixed with polypropylene composites in an internal mixer. The aim is to find the best protocol able to discriminate miscanthus genotypes for their reinforcement capability. The following process parameters were optimized in order to maximize the reinforcement effect of the stem fragment filler: mixing parameters (mixing time, rotor speed and chamber temperature), temperature, fragment content, size and length distributions and coupling agent. The relationship between the process parameters and the mechanical properties of composites were analyzed to evaluate the influence of genotype on reinforcement performance, showing the robustness of the protocol in effectively discriminating genotypes according to their reinforcing capacity. 相似文献
Surface oxygen functionalities (particularly C−O configuration) in carbon materials have negative influence on their electrical conductivity and Na+ storage performance. Herein, we propose a concept from surface chemistry to regulate the oxygen configuration in hierarchically porous carbon nanosheets (HPCNS). It is demonstrated that the C−O/C=O ratio in HPCNS reduces from 1.49 to 0.43 and its graphitization degree increases by increasing the carbonization temperature under a reduction atmosphere. Remarkably, such high graphitization degree and low C−O content of the HPCNS-800 are favorable for promoting its electron/ion transfer kinetics, thus endowing it with high-rate (323.6 mAh g−1 at 0.05 A g−1 and 138.5 mAh g−1 at 20.0 A g−1) and durable (96 % capacity retention over 5700 cycles at 10.0 A g−1) Na+ storage performance. This work permits the optimization of heteroatom configurations in carbon for superior Na+ storage. 相似文献
The rational design of highly active hexagonal boron nitride (h-BN) catalysts at the atomic level is urgent for aerobic reactions. Herein, a doping impurity atom strategy is adopted to increase its catalytic activities. A series of doping systems involving O, C impurities and B, N antisites are constructed and their catalytic activities for molecular O2 have been studied by density functional theory (DFT) calculations. It is demonstrated that O2 is highly activated on ON and BN defects, and moderately activated on CB and CN defects, however, it is not stable on NB and OB defects. The subsequent application in oxidative desulfurization (ODS) reactions proves the ON and C-doped (CB, CN) systems to be good choice for sulfocompounds oxidization, especially for dibenzothiophene (DBT). While the BN antisite is not suitable for such aerobic reaction due to the extremely stable B−O*−B species formed during the oxidation process. 相似文献
Carborane encapsulation was visualized by using fluoroboropyrrole (BODIPY) zwitterionic polymer as fluorescence marker. Firstly, a water-soluble fluorescent probe carrier was prepared by combining the BODIPY derivatives with poly (carboxybetaine methacrylate) (p-CBMA). Two oil-in-water carborane polymers were self-assembled in organic solvents by means of dual ion hydrogen bonding. The ultraviolet and fluorescence spectra were measured with different organic solvents, and the spectra ranged from 531 to 555 nm. The dynamic self-assembly effect was tested by TEM, and the internal microscopic phenomena of the water-soluble polymer were further observed. It was confirmed that two kinds of BODIPY zwitterionic polymers were firmly encase the fat-soluble carborane, forming an oval shape. Carboranes are water-soluble, can achieve biocompatible expression, and can visualize the degree of aggregation in the targeted cells through its own fluorescence effect. Subsequent imaging of the cells showed that both polymers entered the targeted cells. 相似文献
This study seeks to investigate the removal efficiency of particulate matter (PM) from the actual diesel exhaust at various reaction temperatures by using non-thermal plasma (NTP). The effect of the reaction temperature on removal efficiency was reflected by the change in the concentration of particles in different modes and the weight fraction of volatile organics in PM. The Arrhenius equation was used to determine the apparent activation energies Ea of the soot in PM. In addition, the difference in the oxidation reaction at various reaction temperatures and the effect of NTP on the properties of PM were discussed. After considering the decreasing ranges of the total concentration and the weight of the PM, it was determined that 120 °C is the optimal temperature choice for PM removal. The decreasing range of the total concentration reached 57.13% and 66.79% of PM was removed when the PM is measured by weight. NTP has better effect on the removal of smaller particles. The weight fraction of the volatile fraction markedly decreases after the reaction and the apparent activation energy of soot noticeably decreased. The oxidizability of the excited species in NTP was enhanced with the increase of the reaction temperature. However, the excited species concentration declined concurrently, resulting in the occurrence of the optimized range of reaction temperature. The particles were removed by the oxidation that occurred on the surface of the primary particle and the disintegration of the structure of the particles.
Daylight visible fluorescent dye (10% v/v) mixed with water was aerially applied on mature field cotton with electrostatic and rotary atomizer nozzles. The spray rates for the electrostatic and rotary atomizer nozzles were 9.4 and 28 L/ha, respectively. Images of spray droplets on cotton leaves were digitally analyzed with ImageJ software. Charged spray cloud increased deposition nearly two to three times on adaxial and abaxial surfaces, respectively, of top canopy leaves compared to uncharged spray. Canopy penetration of the spray into the lower layers of the plant foliage was unaffected by spray application method. 相似文献
For the magnetic levitation system consisting of a high-Tc superconductor and permanent magnet, the relation curve of magnetic force with gap between these two components is known as a hysteresis loop, that is, the approaching and departing portions envelop a complete one, and generally these two portions do not cross each other. However, in some special cases this crossing arises, and makes the complete loop broken. In this paper, by the numerical simulation of the magnetic force-gap curve in large numbers of physical and geometrical parameters, two typical crossings were found. To investigate the crossing and explore its physical causes, for one of the crossings, the current density in the superconductor was further calculated and its magnitude and vector distribution at the gaps nearby where the crossing arises were obtained. Based on these calculation results and an adequate discussion, the conclusion was induced that the crossing in the magnetic force-gap hysteresis curve results from applied magnetic field’s incomplete and insufficient penetrating in superconductor. 相似文献
In this work, we reported the effect of Li2CO3 addition on the structural, optical, ferroelectric properties and electric-field-induced strain of Bi0.5(Na,K)0.5TiO3 (BNKT) solid solution with CaZrO3 ceramics. Both rhombohedral and tetragonal structures were distorted after adding Lithium (Li). The band gap values decreased from 2.91 to 2.69 eV for 5 mol% Li-addition. The maximum polarization and remanent polarization decreased from 49.66 μC/cm2 to 27.11 μC/cm2 and from 22.93 μC/cm2 to 5.35 μC/cm2 for un-doped and 5 mol% Li- addition BNKT ceramics, respectively. The maximum Smax/Emax value was 567 pm/V at 2 mol% Li2CO3 access. We expected this work will help to understand the role of A-site dopant in lead-free ferroelectric BNKT materials. 相似文献