MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 5
·1-10
·
IF 6.232
Li Hong-Xing,Xie Tian-Peng,Yan Ke-Qian,Xie Sheng-Ming,Wang Bang-Jin,Zhang Jun-Hui,Yuan Li-Ming
A hydroxyl-functionalized homochiral porous organic cage (POC) was synthesized and characterized by FTIR, NMR, thermogravimetric analysis (TGA), MALDI-TOF-MS, and elemental analysis. The synthesized homochiral POC was used as stationary phase to prepare a capillary gas chromatography (GC) column by a static coating method. The fabricated column shows excellent selectivity not only for the separation of positional isomers but also for the resolution of various racemates. Thirty-nine racemates have been resolved on the column, including alcohols, diols, halohydrocarbons, epoxides, esters, lactones, ketones, ethers, and organic acids. Compared to the commercial β-DEX 120 column and previously reported chiral POCs (CC3-R, CC9, and CC10)-coated columns, there are 11, 10, 24, and 15 tested racemates that cannot be resolved on β-DEX 120 column, CC3-R column, CC9 column, and CC10 column, respectively. This reveals that the fabricated column has prominent complementarity or superior separation performance to these columns in enantioseparation. Besides, the fabricated column can achieve some enantioseparations which are not possible using all previously reported chiral POC-based columns. Some positional isomers (xylenes, dichlorobenzenes, dibromobenzenes, nitrochlorobenzenes, and nitrobromobenzenes) were also separated with high-resolution values. The column exhibits good repeatability, reproducibility, and stability. The relative standard deviation (RSD) values of retention times were 0.03–0.18%, 0.11–0.92%, and 2.1–6.6% for run-to-run ( n = 5), day-to-day ( n = 5), and column-to-column ( n = 3), respectively. The experimental results demonstrate the great potential of POCs for practical application in GC.
A hydroxyl-functionalized homochiral porous organic cage was used as stationary phase for gas chromatography separation of racemates and positional isomers. The resolution of racemates mainly depended on hydrogen bonding, π-interaction, host-guest inclusion, steric fit, etc., while separation of positional isomers by shape-selective guest binding.
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NANOTECHNOLOGY
·
2020
·Vol. 31
·期 16
·165503
·
IF 3.551
Hang Song,Jie Liu,Haiyang Lu,Chao Chen,Long Ba
A gas sensor made from graphene vertical field effect transistor (VGr-FET) has been fabricated using graphene as the source electrode, C60 thin film as the semiconductor layer and aluminum thin film as the drain electrode. The on/off ratio of transistor gated by bottom electrode with ionic liquid gel as dielectric layer is derived to be 103 from measured source–drain current Ids. The apparent energy barrier height between the graphene and polycrystalline fullerene was calculated from the model of heterojunction diode I–V response curves. The barrier height φBH was altered by the gating potential vertically applied on graphene sheet, resulting the large on/off ratio of the transistor. The effect of surface adsorption of water vapor, oxygen, ammonia and isoprene gas phase molecules on the Ids was measured. The lower limit of detection (LOD) for ammonia (86 ppb) than that of isoprene (420 ppb) is attributed to the donor nature of ammonia contact with p-type graphene, and the adsorbed donor leads to a corresponding positive gating effect to the VGr-FET. This facile, low cost and quick responsive device shows promise for early diagnose of severe human respiratory diseases.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Shuang Cao,Ning Sui,Peng Zhang,Tingting Zhou,Jinchun Tu,Tong Zhang
Gas sensors have become increasingly significant because of the rapid development in electronic devices that are applied in detecting noxious gases. Adjusting the crystal phase structure of sensing materials can optimize the band gap and oxygen-adsorptive capacity, which influences the gas sensing characteristics. Therefore, titanium dioxide (TiO 2 ) materials with different crystal phase structures including rutile TiO 2 nanorods (R-TiO 2 NRs), anatase TiO 2 nanoparticles (A-TiO 2 NRs) and brookite TiO 2 nanorods (B-TiO 2 NRs) were synthesized successfully via one-step hydrothermal process, respectively. The gas sensing characteristics were also investigated systematically. The sensors based on R-TiO 2 NRs displayed the higher response value (12.3) to 100 ppm acetone vapor at 320 °C compared to A-TiO 2 NRs (4.1) and B-TiO 2 NRs (2.3). Furthermore, gas sensors based on R-TiO 2 NRs exhibited excellent repeatability under six cycles and good selectivity to acetone. The outstanding sensing properties of gas sensors based on R-TiO 2 NRs can be ascribed to relatively narrow band gap and more oxygen vacancies of rutile phase, which showed a probable way for design gas sensors based on metal oxide semiconductors with remarkable gas sensing performances by the crystal phase adjustment engineering in the future.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Yujie Chen,Wei Xu,Muhammad Shafiq,Jincheng Tang,Junxiang Hao,Xianrui Xie,Zhengchao Yuan,Xianghao Xiao,Yu Liu,Xiumei Mo
To achieve optimal functional recovery of articular cartilage, scaffolds with nanofibrous structure and biological function have been widely pursued. In this study, two-dimensional electrospun poly( l -lactide- co -ε-caprolactone)/silk fibroin (PLCL/SF) scaffolds (2DS) were fabricated by dynamic liquid support (DLS) electrospinning system, and then cross-linked with hyaluronic acid (HA) to further mimic the microarchitecture of native cartilage. Subsequently, three-dimensional PLCL/SF scaffolds (3DS) and HA-crosslinked three-dimensional scaffolds (3DHAS) were successfully fabricated by in situ gas foaming and freeze-drying. 3DHAS exhibited better mechanical properties than that of the 3DS. Moreover, all scaffolds exhibited excellent biocompatibility in vitro . 3DHAS showed better proliferation and phenotypic maintenance of chondrocytes as compared to the other scaffolds. Histological analysis of cell-scaffold constructs explanted 8 weeks after implantation demonstrated that both 3DS and 3DHAS scaffolds formed cartilage-like tissues, and the cartilage lacuna formed in 3DHAS scaffolds was more mature. Moreover, the reparative capacity of scaffolds was discerned after implantation in the full-thickness articular cartilage model in rabbits for up to 12 weeks. The macroscopic and histological results exhibited typical cartilage-like character and well-integrated boundary between 3DHAS scaffolds and the host tissues. Collectively, biomimetic 3DHAS scaffolds may be promising candidates for cartilage tissue regeneration applications.
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Reaction Chemistry & Engineering
·
2021
·Vol. 7
·期 3
·590-598
·
IF 4.239
Runzhe Liang,Xiaonan Duan,Jisong Zhang,Zhihong Yuan
In recent years, self-optimization strategies have been gradually utilized for the determination of optimal reaction conditions owing to their high convenience and independence from researchers' experience. However, most self-optimization algorithms still focus on homogeneous reactions or simple heterogeneous reactions. Investigations on complex heterogeneous gas–liquid–solid reactions are rare. Based on the Nelder–Mead simplex method and Bayesian optimization, this work proposes a reaction optimization framework for optimizing complex gas–liquid–solid reactions. Three gas–liquid–solid reactions including the hydrogenations of nitrobenzene, 3,4-dichloronitrobenzene, and 5-nitroisoquinoline are investigated, respectively. Reaction parameters (temperature, hydrogen pressure, liquid flow rate, and gas flow rate) are optimized. Compared with the traditional OVAT method, the proposed Bayesian based optimization algorithm exhibits remarkable performance with higher yields (0.998, 0.991 and 0.995, respectively) and computational efficiency.
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JOURNAL OF CHROMATOGRAPHY A
·
2019
·
IF 3.858
Tiantian Shi,Meiling Qi,Xuebin Huang
Developing highly selective stationary phases is essential to address the issues for separation of analytes with similar properties and various components in complex samples. Herein, we report a new triptycene-based material functionalized with polycaprolactone moieties (TP-PCL) as the stationary phase with high-resolution performance for gas chromatography (GC). The TP-PCL capillary column exhibited column efficiency of 5555 plates/m and moderate polarity. On the column, dozens of mixtures of positional and structural isomers can be well resolved, involving benzene derivatives with varying substituents (alkyl, halo, nitro, hydroxyl, amino), naphthalene derivatives, alkanes and alcohols. It exhibits advantageous performance for high resolution of the critical pairs of alkylbenzenes, phenols, anilines and alkanes over the PCL column and commercial DB-35 MS column with similar polarity. Moreover, the TP-PCL column showed excellent separation repeatability and reproducibility with RSD values of 0.02%−0.07% for run-to-run ( n = 4), 0.11%−0.18% for day-to-day ( n = 4) and 2.1%−4.7% for column-to-column ( n = 4). In addition, it exhibited distinctly enhanced thermal stability in contrast to the PCL column. Its application to analysis of the essential oil from Artemisiae argyi proves its good potential for practical use.
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JOURNAL OF CHROMATOGRAPHY A
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2019
·
IF 3.858
Jun He,Lining Yu,Xuebin Huang,Meiling Qi
This work presents the investigation of two triptycene-based materials (TP-3OB and TP-3Im) as the stationary phases for gas chromatographic (GC) separations. The TP-3OB and TP-3Im capillary columns fabricated by static coating exhibited column efficiency of 3000–3500 plates/m for n -dodecane at 120 °C. Also, their McReynolds constants and Abraham system constants were determined to characterize their polarity and molecular interactions with analytes. On the basis of the unique 3D TP architecture, the TP-3OB and TP-3Im stationary phases exhibited complementary high-resolution performance for analytes of a wide ranging polarity, including alkylbenzenes , alkylnaphthalenes, halobenzenes, phenols and anilines, respectively. Moreover, the TP-based columns exhibited good repeatability and reproducibility on the retention times of analytes with the relative standard deviation (RSD) values in the range of 0.01–0.14% for run-to-run, 0.11–0.47% for day-to-day and 0.68–4.7% for column-to-column, respectively. Additionally, their applications for the determination of isomer impurities in the commercial reagents of o- dichlorobenzene , p-/m- diethylbenzene, o -toluidine and 2,3 -/ 3,5-xylidine proved their good potential for practical analysis. This work demonstrates the promising future of the triptycene-based stationary phases for chromatographic separations.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Shendan Zhang,Mingjie Yang,Kunyu Liang,Ayse Turak,Bingxue Zhang,Da Meng,Chuanxi Wang,Fengdong Qu,Wenlong Cheng,Minghui Yang
Nanosized Pt-loaded Fe 2 O 3 nanocubes are prepared through, successively, a simple hydrothermal reaction, two-step annealing process and finally reduction with NaBH 4 of H 2 PtCl 4 . The resultant Pt decorated Fe 2 O 3 nanocubes, made up of Fe 2 O 3 nanoplatelets, are hierarchical, hollow and porous, with an average edge length of 200–300 nm. The sensor based on Pt decorated Fe 2 O 3 nanocomposites exhibits higher response (R air /R gas = 25.7) to 100 ppm of acetone gas at lower temperature (139 °C), with a short response-recovery time (3 s/22 s), compared with pure Fe 2 O 3 nanocubes sensor. The Pt-Fe 2 O 3 nanocomposite sensor shows excellent potential to act as a low cost, low temperature sensor for acetone gas, with high acetone selectivity under high humidity conditions and with the interference of other gases. Under various environmental conditions designed to mimic exhaled air, the sensor is able to detect ppb amounts of acetone, with high repeatability and stability, making it suitable for applications such as oral diabetic sensors. The attractive chemical and electronic sensitizations of partially oxidized Pt nanoparticles are responsible for the enhancement of acetone sensing performance. Based on the high acetone selectivity, high stability and fast dynamic response, the Pt enhanced Fe 2 O 3 nanocubes sensor is an exceptionally suitable candidate for a low cost acetone sensor, and the proposed approach provides a route to develop gas sensors that can operate at low temperatures for a wide variety of applications.
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APPLIED RADIATION AND ISOTOPES
·
2019
·
IF 1.343
Chao-Feng Chen,Li-Tao Yang,Yan-Jun Huang,Zhi-Hong Shang-Guan,Gui-Ying Guo,Jian-Lin Yao,Xiang-Dong Sha
A measurement method of 85 Kr using an internal gas proportional counter (IGPC) is presented in this study. The operation conditions of the IGPC were determined and optimized, including the operating voltage, pressure, sample volume, interference from other gas components such as nitrogen or air, and mitigation of the memory effect. The IGPC was calibrated using certified standards, and the detection efficiency was approximately 58% for typical samples. A lower limit of detection of approximately 0.11 MBq/m 3 (Kr) was achieved after counting for 5 h with 1 mL pure Kr, corresponding to the atmospheric activity concentration of 0.18 Bq/m 3 (air). It was shown that the IGPC could be used effectively for measuring 85 Kr.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Changchao Jia,Tao Dong,Meng Li,Peng Wang,Ping Yang
TiO 2 hollow hierarchical architectures with anatase and rutile phases are fabricated. The hierarchical structure uniformly decorated with SnO 2 nanoparticles endows a fascinating sensing performance for detecting triethylamine (TEA). Hierarchical structure provides a close connection between anatase/rutile TiO 2 and SnO 2 , which is in favor of efficient electrons transfer . It is found that TiO 2 @SnO 2 as a novel sensing material has high response at low level of TEA and rapid responding speed in comparison with individual TiO 2 components. In the case of 5 ppm TEA gas under the operation temperature of 240 °C, the response value of TiO 2 @SnO 2 sample is up to 21.6, which is three times higher than that of TiO 2 sample. The responding speed of TiO 2 @SnO 2 sensors elevates 28% in comparison with TiO 2 . This result is utilizable for developing the high efficiency gas sensors using hollow hierarchical architecture.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Yixue Li,Zhongxiao Song,Yanan Li,Shuai Chen,Sha Li,Yanhuai Li,Hairong Wang,Zuankai Wang
Surface structure control at the atomic scale is an efficient strategy for improving the performance of gas sensing. Herein, hierarchical hollow MoS 2 microspheres with enhanced performance for NO 2 gas sensing were synthesized via a facile hydrothermal method. The introduction of micro-nano hierarchical structure improved the exposure of active edge sites of MoS 2 , and the efficiency of gas and carriers exchange and transportation during the reaction, which synthetically contribute the sensing performance enhancement. With additional optimization of reaction conditions, the hierarchical hollow MoS 2 microspheres show excellent sensing performance with 3.1 times enhancement compared with the contrast sample of smooth solid structure. The rapid and sensitive response, decreased working temperature, as well as the prominent selectivity, enable the material with attractive sensing performance for NO 2 detection. This study provides new opportunities on the surface morphology control at both the micro- and nanoscale for enhancing the sensing performance of MoS 2 .
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JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Yongmin Xie,Weizi Cai,Jie Xiao,Yubao Tang,Jiang Liu,Meilin Liu
Solid oxide fuel cells (SOFCs), with yttrium stabilized zirconia (YSZ) as electrolyte, composite of strontium-doped lanthanum manganate (LSM) and YSZ as cathode, and cermet of silver and gadolinium-doped ceria (GDC) as anode, are prepared and tested with 5wt% Fe-loaded activated carbon as fuel and ambient air as oxidant. It is found that electricity and CO gas can be cogenerated in the direct carbon SOFCs through the electrochemical oxidation of CO and the Boudouard reaction . The gas–electricity cogeneration performances are investigated by taking the operating time of the DC-SOFCs as a measure of rate decrease of the Boudouard reaction. Three single cells and a two-cell-stack are tested and characterized in terms of electrical power output , CO production rate, electrical conversion efficiency, and overall conversion efficiency. It turns out that a rapid rate of the Boudouard reaction is necessary for getting high electrical power and CO production. Taking the emitted CO as part of the power output, an overall efficiency of 76.5% for the single cell, and of 72.5% for the stack, is obtained.
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