ISSN 0253-2778

CN 34-1054/N

2019 Vol. 49, No. 4

Display Method:
Original Paper
Improved electrochemical reversibility of Li-Ni-Te-O cathode by local domain structure optimization
QI Jiaxin, WANG Xingbo, SU Xiaozhi, XIE Hui, REHMAN Zia ur, TAO Shi, CHU Wangsheng
2019, 49(4): 259-267. doi: 10.3969/j.issn.0253-2778.2019.04.001
Novel layered oxide Li1+xNi3/4-5/4xTe1/4+1/4xO2 (x=0, 0.14, 0.33, 0.46, 0.50 and 0.60) cathodes were synthesized by a solid-state reaction method. A unique P1-like domain with a short-range order around Ni ions was found in the monoclinic C2/m crystal with x=0.33, which displays a loosely bonded local structure and increased Li+ mobility, enabling superior structural as well as electrochemical reversibility. The enhanced properties investigated by ex situ X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical characterization were corroborated to originate from the stable short- and long-range ordering structure along with the Ni electron redox. This study may open up new avenues for the development of Li-rich cathode materials with sufficiently good performance.
A glucose biosensor based on graphene-Prussian blue-chitosan composite film fabricated by electrodeposition
LIU Hao, WU Shouguo
2019, 49(4): 268-275. doi: 10.3969/j.issn.0253-2778.2019.04.002
The layer-by-layer structured composite film of graphene-Prussian blue (PB)-chitosan (CS) was fabricated on a glassy carbon electrode by three-step electrodeposition method and used for glucose sensing. Graphene nanosheets were directly deposited onto the electrode through reduction of graphene oxide by cyclic potential scanning. Then, a glucose biosensor was fabricated by electrodepositing PB nanoparticles and glucose oxidase (GOD)-chitosan hybrid film (GOD-CS) on the graphene modified electrode successively. The surface of the resulting modified electrode was characterized by electrochemical methods and scanning electron microscopy. Under optimal conditions, the biosensor shows high sensitivity (50.29 mA· L·mol-1·cm-2), low detection limit (12 μmol·L-1) and fast response time (3 s). A linear dependence of the catalytic current upon glucose concentration is obtained in a wide range from 0.02 to 10 mmol·L-1. In addition, the sensor also performs well for measuring glucose concentrations in human blood serum samples without any pretreatment.
Production of 5-hydroxymethylfurfural from carbohydrates in a biphasic system
ZHAO Yan, LIU Yin, ZHU Jinbo
2019, 49(4): 276-281. doi: 10.3969/j.issn.0253-2778.2019.04.003
Cheap catalyst aluminum silicate was combined with HCl to efficiently convert carbohydrates to 5-hydroxymethylfurfural (HMF) in a biphasic system. Glucose can yield 61.5% of 5-HMF in an H2O/n-butanol biphasic system at 453 K within 30 min. Polysaccharides (sucrose, maltose, starch and cellulose) can also be converted to HMF effectively in this biphaisc system at 453 K for 40 min. In addition, aluminum silicate can be reused over five cycles without a significant decrease in its activity. Such catalytic system has the potential to become an effecient and cost-effective approach to the conversion of carbohydrates into bio-fuels and platform chemicals.
Fast and efficient removal of lead from low concentration solutions using silicotitanate
ZHAO Xudong, WENG Hanqin, SHENG Liusi, YU Guobing, LIN Mingzhang
2019, 49(4): 282-289. doi: 10.3969/j.issn.0253-2778.2019.04.004
Sodium crystalline silicotitanate (Na-CST) and niobium substituted crystalline silicotitanate (Na-Nb/CST), which were synthesized using the hydrothermal method and characterized by X-ray diffraction (XRD), BET and scanning electron microscopy (SEM), were used to separate Pb2+ from aqueous solutions. The adsorption experiments show that their maximum adsorption ability is within pH 4.00~6.50. The adsorption process reaches equilibrium within 60 min, and the maximum adsorption quantity of Na-CST and Na-Nb/CST is 70.1 and 70.7 mg·g-1, respectively. Both materials are able to remove more than 94% of Pb2+ from water when Pb2+ concentration is at 10-9kg·L-1 level. Most interestingly, the concentration of Pb2+ could be lower than 3×10-9kg·L-1 after adsorption, much lower than the standard set by of the World Health Organization for the quality of drinking water, 1×10-8kg·L-1.
CH3NH3PbI3 perovskite quantum dots integrated in luminescent solar concentrators
YAN Sen, ZHANG Yi, BAO Jun, ZHANG Ningning, ZHANG Feng, SUN Song, GAO Chen
2019, 49(4): 290-296. doi: 10.3969/j.issn.0253-2778.2019.04.005
Luminescent solar concentrators (LSCs) have the potential to be integrated into buildings, which can serve as distributed energy generation units and achieve a high concentrating ratio without the traditional cooling and tracing systems. Colloidal quantum dots (QDs) are promising candidates as emissive chromophores in LSCs, but self-absorption loss is still a hindrance to the enhancement of the efficiency of QD-LSCs. CH3NH3PbI3 perovskite QDs were synthesized by ligand-assisted reprecipitation (LARP) technique that is low cost and convenient for scale-up fabrications. CH3NH3PbI3 perovskite QD solution was used to fabricate a relatively large size LSC with a dimension of 78 mm×78 mm×7 mm. By optimizing synthesis of CH3NH3PbI3 perovskite QDs, absorption and emission spectra were tuned to minimize the overlap, thus reducing self-absorption losses in waveguide transmission. Thanks to the suppressed reabsorption, the LSC with a dimension of 78 mm×78 mm×7 mm fabricated from CH3NH3PbI3 perovskite QDs exhibited an optical efficiency as high as 24.5% and a power conversion efficiency of 3.4%. It shows that CH3NH3PbI3 perovskite QDs as suitable emitters could be excellent candidates for efficient large-area LSCs in future building-integrated photovoltaics.
Nanobody cluster imaging probe based on sortase and transglutaminase
TIAN Yao, WU Tiantian, LIU Yangzhong
2019, 49(4): 297-301. doi: 10.3969/j.issn.0253-2778.2019.04.006
Sortase and transglutaminase was rendered for preparing a targeted protein cluster probe, which is composed nanobody and green fluorescence protein (sfGFP). A unique substrate, which can be recognized by both sortase and transglutaminase, was designed for nanobody and sfGFP conjunction by solid phase synthesis. The targeted protein cluster probe, namely KK-sfGFP(Nb), can specificly bind to the EGFR overexpressed cells and shows green fluorescence as signal. The KK-sfGFP(Nb) exhibits fast accumulation in mouse xenograft tumor and the fluorescence signal gradually metabolizes within 9 h.
Preparation of hollow CdS/PANI nanocomposite microspheres for photocatalytic hydrogen evolution
YUAN Wei, CUI Xiaoling, ZHANG Zhen, TAI Chen, SONG Yuanrui, LIU Huarong
2019, 49(4): 302-310. doi: 10.3969/j.issn.0253-2778.2019.04.007
Hollow CdS/PANI nanocomposite microspheres were successfully synthesized by the polymerization of aniline in the presence of hollow CdS microspheres, which were prepared via “hard core template” approach. The morphology and structures of nanocomposites could be controlled by adjusting the amount of aniline. The as-prepared photocatalysts were characterized by transmission electronic microscope (TEM), X-ray diffraction (XRD),
Molecular distribution of coal pyrolysis products of bituminous and anthracite from Huainan coalfield by vacuum pyrolysis furnace coupled with mass spectrometer under different electron ionization energies
YIN Hao, LIU Guijian, NIU Zhiyuan, FENG Airong
2019, 49(4): 311-320. doi: 10.3969/j.issn.0253-2778.2019.04.008
Bituminous, anthracite and natural coke from Huainan coalfield were investigated by a vacuum pyrolysis furnace coupled with mass spectrometer (MS) directly under different electron ionization (EI) energies.Through total intensity of ions (TII), total number of ion species (TNI), number average molecular weight (Mn), and weight average molecular weight (Mw) of the three coals pyrolysis products, it can be obtained that TNI, Mn and Mw of bituminous pyrolysis products are similar to those of anthracite pyrolysis products, which indicates that the molecular distribution of the bituminous pyrolysis products is similar to anthracite pyrolysis products, but is much different to natural coke pyrolysis products. Through the ratios of specific mass fragment ions of C7H7+/C6H6·+and C4H9+/C6H6·+in the three coals pyrolysis products, it can be obtained that the ratios of C7H7+/C6H6·+ in the three coals pyrolysis products are similar, but that of C4H9+/C6H6·+ in natural coke pyrolysis products is more than the ratio of C4H9+/C6H6·+in the pyrolysis products of bituminous and anthracite, which indicates that the relative content of alkylbenzene to benzene in the three coals pyrolysis products is similar,and that the relative content of aliphatic compounds to benzene in natural coke pyrolysis products is more than that in bituminous and in anthracite.And through all MS data, the proper range of EI energy for coal pyrolysis is from 65 eV to 75 eV.The vacuum pyrolysis furnace coupled with mass spectrometer fleetly can be useful to the quick investigation of molecular distribution characteristics of coal pyrolysis products for coal non-fuel utilization.
Investigation on the source of air pollutants in Hefei city based on backward trajectory model
LUO Biao, LIU Xuan
2019, 49(4): 321-328. doi: 10.3969/j.issn.0253-2778.2019.04.009
The transport process of air pollutants in Hefei in 2014 was simulated, using the HYSPLIT(hybrid single-particle Lagrangian integrated trajectory)-4 backward trajectory model and NCEP(National Centers for Environmental Prediction) reanalysis data, and the mass concentration data of conventional atmospheric pollutants such as SO2, NO2, PM10 and PM2.5 were also used. The results showed that the air trajectories in Hefei had an obvious seasonal variation, and that the potential sources of pollutants in different seasons in Hefei were different.In January, the airflow in the northwest direction accounted for 43%, and the local airflow between cities accounted for 57%. The concentrations of SO2, NO2, PM10, and PM2.5 were very large. In April, the airflow from the Yangtze River Delta region accounted for 58%. The concentrations of various pollutants were very low. In July, the local airflow between cities accounted for 48%, and the airflow from the Yangtze River Delta region accounted for 24%. The PM10 concentration was higher, and the concentrations of other pollutants were lower. In October, the local airflow between cities accounted for 50%, the northern airflow accounted for 27%, and the airflow from the Yangtze River Delta region accounted for 23%. The PM10 concentration was higher, and the concentrations of other pollutants were lower. The main sources of air pollution in Hefei were mainly from the northern air masses, the air masses in the Yangtze River Delta region, and the local urban air masses.
Research on smoke entrainment rate of urban highway tunnel near the fire source area
ZHANG Xuanxuan, NIU Guoging, LI Yuanzhi
2019, 49(4): 329-342. doi: 10.3969/j.issn.0253-2778.2019.04.010
The mass entrainment rate is a key factor that can not be ignored when preventing and controlling flue gas. The full-scale urban highway tunnel was taken as the research object, and dimensionless analysis and numerical simulation methods were used to investigate the influence of fire power, effective ceiling height, fire source lateral position and tunnel width on the mass entrainment rate of flue gas. Through the analysis of the suitability of the rolling suction model proposed by previous researchers and the variation of the entrainment rate under the 20 simulation conditions, the results show that for the large and small power sources with different entrainment mechanisms, the entrainment models proposed by predecessors at the stage II and III have certain limitations. The mass entrainment rate in the near-field area of the fire source was measured by the hood method. And the mass flow rate of the stage II and III sections was calculated by the discretization method with the accuracy of the results being improved. Based on the dimensional analysis method, the dimensionless smoke entrainment model was constructed, which is associated with the key factors, such as the fire power, the tunnel width, the fire source position, and the effective ceiling height. And the quantitative relation formulas of gas mass entrainment rate in stage II and III were obtained by numerical simulation and data fitting.