INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2020
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IF 4.939
Guanjun Liu,Fan Yang,Wenbo Liu,Weicheng Jiao,Xiaodong He,Rongguo Wang
High gas barrier polyethylene (PE) composites containing non-oxidized graphene flakes (GFs) were fabricated through solution blending. GFs were synthesized through ultrasonic-assisted electrochemical exfoliation of graphite. Then, GFs were functionalized via directly inducing PE molecular crystallization along their surface under proper temperature and PE/GFs ratio. The composites with only 0.5 wt% GFs gave a helium leak rate of 6.29 × 10 −8 Pa m 3 /s at 0.6 MPa, outperforming pure PE with a decrease of 83.4%. In addition, the interface interaction between PE and GFs is very weak, and the cohesive energy is only 0.1448 J m −2 . Therefore, at high GFs concentrations (>0.5 wt%), the continuous weak interfaces between the GFs interconnected networks and PE will reduce the effective diffusion path to a certain extent, leading to the reduction of gas barrier efficiency. In general, this method offers great promise for barrier materials that can be utilized in lightweight high-pressure gas storage vessels.
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
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2020
·Vol. 103
·期 6
·3905-3916
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IF 3.502
Yongjie Liu,Yue Wang,Yu Zhang,Zhixiong You,Xuewei Lv
Ammonia gas can be simultaneously used as a reductant and nitrogen source to prepare TiN from titania. In this work, the mechanisms on reduction and nitridation of micrometer-sized anatase with ammonia gas have been investigated, using both thermodynamic and experimental studies. The thermodynamic analysis indicated that reduction and nitridation of TiO 2 by NH 3 was feasible. Anatase will undergo different paths to form TiN, depending on the reaction temperature. Upon heating, NH 3 was seen to partially decompose into N 2 and H 2 , although the actual NH 3 decomposition ratio was less than the theoretical value. The experimental results indicated that the obtained titanium nitride was non-stoichiometric (TiN x O 1 −x , x ≤ 1), as it contained a certain amount of oxygen. Based on the phase transformation and X-ray photoelectron spectroscopy analysis, the reduction and nitridation routes were deduced: TiO 2 reacted with NH 3 to form TiN x O 1− x directly, at lower temperatures, and followed the path TiO 2 → Ti n O 2n−1 → TiN x O 1− x , at higher temperatures. Ti n O 2n−1 was determined to be Ti 4 O 7 and Ti 3 O 5 at 1100°C and 1200°C, respectively. Reaction temperature and time significantly affected the oxygen and nitrogen contents in TiN x O 1− x , with the lattice parameter of roasted products gradually increasing—approaching those of pure TiN—with an increase in reaction temperature and holding time. At the same time, the content of oxygen in TiN x O 1− x decreased, and its nitrogen content correspondingly increased.
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NEW JOURNAL OF CHEMISTRY
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2020
·Vol. 44
·期 7
·2890-2896
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IF 3.288
Yinhui Yang,Meiling Qi,Jinliang Wang
Here we report a novel hexaphenylbenzene (HPB)-based material functionalized with six tetraphenylethylene units (BPT) with unique conformation-driven selectivity for gas chromatographic (GC) separations. It is composed of a neat aromatic hydrocarbon with a rigid propeller-like conformation. As a result, the BPT capillary column exhibited high column efficiency of 5340 plates per m and high-resolution capability for aromatic to aliphatic isomers with excellent intra-day and inter-day repeatability and between-column reproducibility. The results demonstrate the unique conformation-driven selectivity of the HPB-based stationary phase, which is rarely reported for chromatography. Moreover, its application in the determination of isomer impurities in commercial products proved its good potential for practical GC analysis. This work presents a new perspective for developing selective stationary phases by engineering their structures.
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Nanomaterials
·
2020
·Vol. 10
·期 4
·774
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IF 4.324
Fang Peng,Yan Sun,Yue Lu,Weiwei Yu,Meiying Ge,Jichao Shi,Rui Cong,Jiaming Hao,Ning Dai
In this work, the high crystalline copper oxide (CuO) nanoparticles were fabricated by a hydrothermal method, and their structural properties were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The sensing results show that CuO nanoparticles exhibit enhanced sensitivity and good selectivity for hydrogen sulfide (H2S) gas at a low temperature. There are two working mechanisms involved in the H2S sensing based on CuO nanoparticle sensors. They are the H2S oxidation mechanism and the copper sulphide (CuS) formation mechanism, respectively. The two sensing mechanisms collectively enhance the sensor’s response in the H2S sensing process. The Cu–S bonding is stable and cannot break spontaneously at a low temperature. Therefore, the CuS formation inhibits the sensor’s recovery process. Such inhibition gradually enhances as the gas concentration increases from 0.2 ppm to 5 ppm, and it becomes weaker as the operating temperature rises from 40 °C to 250 °C. The XPS results confirmed the CuS formation phenomenon, and the micro Raman spectra demonstrated that the formation of CuS bonding and its decomposition can be effectively triggered by a thermal effect. Gas-sensing mechanism analysis supplied abundant cognition for the H2S sensing phenomena based on CuO materials.Keywords:CuO;H2S;mechanism;oxidation;CuS formation
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PubMed
高影响因子
RSC Advances
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2020
·Vol. 10
·期 5
·2740-2746
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IF 3.119
Jiayan Deng,Min Peng,Zhanyang Gao,Yi Wang,Baoshan Wang,Wenjun Zhou,Ruichao Peng,Yunbai Luo
Sulfur hexafluoride (SF6), which is known as a superior electrically insulating and arc-quenching medium, plays a decisive role in the modern transmission and distribution network of electric energy, especially in high-voltage power networks. However, the ever-increasing usage of SF6 also leads to the continuous escalation of atmospheric SF6 levels, which is considered to be the main cause of the greenhouse effect. To decrease this environmental impact, eco-friendly alternatives to SF6 have been researched for decades. To date, no significant success has been made regarding replacement gases for transmission networks. Some potential alternatives have comparatively lower global warming potential (GWP) but involve technical trade-offs. Thiazyl trifluoride, which has some excellent chemical and electric properties, is a novel substitution candidate for SF6. In this article, an efficient synthetic route starting from sulfur monochloride and followed by ammonization and fluorination was proposed. The structures of the intermediates and the target products were determined by X-ray diffraction (XRD), infrared spectroscopy (IR), and gas chromatography-mass spectrometry (GC-MS). The effects of some determining factors on the yield and purity, including the molar ratio of the reactants, recrystallization conditions and condensation temperature, were also investigated. The results showed that the overall yield of thiazyl trifluoride was approximately 25%, while the purity could be up to 90.6% under optimal conditions.
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PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2020
·
IF 7.1
Da Meng,Shendan Zhang,Tiju Thomas,Ruiyang Zhao,Ying Shi,Fengdong Qu,Minghui Yang
In this paper, a novel fuel cell-type methanol gas sensor based on platinized mesoporous titanium nitride is fabricated. Mesoporous TiN, synthesized from ammonolysis of Zn-containing oxide precursor, is utilized as a support for platinum for both anode and cathode. Its performance is compared to that of Vulcan XC-72R carbon blacks. Hot press method is used for the fabrication of the sensor device. The results for methanol gas detection at room temperature reveal that Pt/TiN sensor has enhanced sensitivity. The response current towards 50 ppm methanol reaches 9.68 μA, which is ∼20 times higher than that of Pt/C sensor (0.41 μA). The Pt/TiN sensor also exhibits excellent repeatability, selectivity and long-term stability. This work reveals the potential of titanium nitride as support materials for gas sensing technologies.
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高影响因子
ENERGY
·
2020
·
IF 6.082
Xiaoya Zang,Xuebing Zhou,Lihua Wan,Jing Wang,Deqing Liang
Cyclopentane (CP) is an alkane that combines with water to form hydrates. Here, we investigate the hydrate thermal dynamics and formation kinetics of a synthesized ternary gas mixture of CH 4 /CO 2 /N 2 with CP additives. The results indicated that CP shifts the phase equilibrium conditions of ternary gas mixture hydrates to higher temperature and lower pressure. Under a constant pressure, the largest temperature offset can be approximately 20 K. Meanwhile, the ternary gas mixture of CH 4 /CO 2 /N 2 formed structure II hydrates with added CP. The kinetics study indicated that the hydrate reaction started immediately when accompanied by stirring. The consumption of CO 2 gas was greater than that of CH 4 and N 2 . The ratio of the volume of CP to the volume of water had a considerable influence on the effective reaction time, CH 4 recovery factor (R CH4 ), and CO 2 split ratio (S CO2 ) under all experimental conditions. R CH4 and S CO2 were higher when the CP-to-water volume ratio was 0.308. The largest values of R CH4 and S CO2 were 3.098 and 0.908, respectively, when the CP-to-water volume ratio was 0.308 at 7.0 MPa and 280.1 K. These results favor the use of CP as an additive to separate CO 2 and purify CH 4 in gas mixtures.
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ENERGY & FUELS
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2020
·
IF 3.421
Dongjing Liu,Zhen Zhang,Fei Luo,Jiang Wu
Graphite-phase carbon nitrides (g-C3N4), composed of only C, N, and some impurity H, have been synthesized by direct thermal polymerization of urea in air and employed to capture elemental mercury (Hg0) from simulated flue gas. The performance and kinetic behavior of g-C3N4 toward Hg0 adsorption are investigated. Its optimal polymerization temperature and ramping rate are 550 °C and 5 K/min, respectively. It shows extraordinary affinity with elemental mercury associated with an Hg0 removal efficiency >77% at 40–240 °C under a nitrogen atmosphere, which is probably attributed to its unique electronic structure property and fluffy tremella-like morphology with ample exposed adsorption sites. The Hg0 may be captured on the sp2-bonded carbon atoms in g-C3N4 by producing carbon–mercury (C–Hg) covalent bonds via Lewis acid–base interaction. The presence of O2 slightly reduces the mercury capture efficiency, while the Hg0 removal efficiency greatly decreases by nearly a half in the presence of H2O, NO, and SO2, which is plausibly owing to the competitive adsorption or deletion of active sites on the g-C3N4 surface. The process of Hg0 adsorption on g-C3N4 is controlled by both intraparticle diffusion and chemisorption processes.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2020
·
IF 7.1
Boxuan Yang,Zheng Zhang,Chen Tian,Wenjing Yuan,Zhongqiu Hua,Shurui Fan,Yi Wu,Xuemin Tian
Gas sensors based on Pd-loaded SnO 2 were prepared with printed zeolite films on the top of the sensor layer to enhance selective response to methane. As expected, Pd-loaded SnO 2 has a sensitive response to CH 4 and VOCs, such as ethanol and acetone vapors. Pt catalyst was dispersed onto the surface to promote the catalytic activity of zeolite. According to the catalytic characterizations, it was indicated that interfered gases, CO and ethanol were catalytically oxidized into CO 2 and water vapor. Whereas the catalytic combustion of methane is a negligible and sensitive response to the interested analyte was significantly promoted. Thus, the selective response to CH 4 was greatly improved even in a mixture of CO and VOCs. Based on the power-law response to oxygen, it was found that the resistive responses of all sensors were highly oxygen-dependent, suggesting that oxygen adsorbates on the surface were involved in the sensing process and no difference with zeolite coated sensors. Thus, it can be concluded that zeolite films printed onto the sensing layer surface serve as a catalytic filter and responsible for the enhanced sensitive and selective response of methane.
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SENSORS AND ACTUATORS B-CHEMICAL
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2019
·
IF 6.393
Xin-Yu Huang,Zong-Tao Chi,Jian Liu,Dong-Hua Li,Xiao-Jun Sun,Cong Yan,Yu-Chong Wang,Hao Li,Xue-Dong Wang,Wan-Feng Xie
Heterostructured semiconductor materials, combining the collective advantages of individuals and synergistic properties, have spurred great interest as a new paradigm toward detecting of volatile organic compounds recently. Direct use of NiS as a sensing material is impractical because the structure of NiS is unstable, exhibiting an undesirable sensing performance. Herein, we firstly report its incorporation into an ethanol gas sensor with a conventional n -type sensitive material of In 2 O 3 , and the gas sensing performance of the NiS@In 2 O 3 nanocomposites has been significantly enhanced. Nanofiber-like NiS and In 2 O 3 were fabricated via a synergetic approach of electrospinning and calcination processes. The diameters of crystalline NiS and In 2 O 3 are about 150 nm and 120 nm, respectively. Then, the NiS@In 2 O 3 nanocomposites were prepared via re-calcination of as-prepared NiS and In 2 O 3 nanofibers. The results show that the sensor based on NiS@In 2 O 3 exhibits a detecting limit of as low as 5 ppm and a short response time of 8 s at the optimum temperature of 300 ºC, which outstripped that (13 s) of pristine In 2 O 3 and pure NiS sensors (21 s) for the detection of ethanol gas. The remarkable improvement of sensing performance can be attributed to the p - n heterojunction in multi-component phases of NiS and In 2 O 3 .
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ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Kuo Yang,Shenfei Zong,Yizhi Zhang,Ziting Qian,Yun Liu,Kai Zhu,Lang Li,Na Li,Zhuyuan Wang,Yiping Cui
A novel kind of array-assisted surface-enhanced Raman spectroscopy (SERS) microfluidic chip (ArraySERS chip) is demonstrated for gas sensing, which has the advantages of both ultrahigh sensitivity and multiplex sensing ability. On the one hand, the introduction of a microstructured triangular array can greatly increase the multiple collision probability between gas molecules and sensing interfaces in the channel. Compared with traditional gas sensors using sealed boxes, where gaseous molecules move only by diffusion, the ArraySERS chip exhibits significantly improved sensitivity. On the other hand, a composite nanoparticle is fabricated as a SERS probe for reading out the fingerprint spectral data, which consists of metal–organic framework (MOF) materials [Zeolitic Imidazolate framework-8 (ZIF-8)] and Au@Ag nanocubes, as well as cysteamine (CA) that serves as the gas-capturing agent. The experimental results show that such a structure of the SERS probe can further increase the sensing ability because of better adsorption of ZIF-8 for gas and the lower SERS background of CA itself. In addition, the simultaneous detection of multiplex gases was easily performed according to their own intrinsic SERS signals. Taking aldehyde gas as a model of a typical air pollutant, trace and multicomponent detection was realized using the ArraySERS chip. The limit of detection value was as low as 1 ppb, which is 2 magnitudes lower than that obtained by traditional methods. This strategy can be well extended for the detection of universal gases and help unleash the potential of existing gas sensors, especially for samples at low concentrations in air.
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高影响因子
Polymer Chemistry
·
2019
·Vol. 10
·期 44
·6021-6030
·
IF 4.76
Linfan Shi,Wenyi Wang,Xiong Fu,Yang Yuan,Bin Zhang,Qiang Huang
Ethylene was introduced into cucurbit[n]urils (CB[n]s, n = 5–7) by molecular encapsulation, for comparison with V-type crystalline starch (V-starch) and α-cyclodextrin (α-CD). The encapsulation capacity of inclusion complexes (ICs) followed the order of CB[5] > V-starch > CB[6] > CB[7] > α-CD. X-ray diffractometry, and 13C solid-state nuclear magnetic resonance and Fourier transform infrared spectroscopy confirmed the presence of ethylene gas in the solid matrices. The controlled release kinetics of the ICs were further studied under different storage temperature (4 and 25 °C) and relative humidity (52.9 and 75.5%) conditions. The Avrami equation was adapted to analyze the controlled release kinetics of ethylene gas, showing a diffusion limited mechanism for CB[n]-ICs under all the storage conditions. The ethylene release rate from CB[n]-ICs was accelerated by increasing ambient temperature, but was not sensitive to relative humidity. CB[5] showed the slowest ethylene release rate among the five solid matrices, up to 700 h under 4 °C storage conditions. Molecular simulation suggested two stable molecular conformations for ethylene molecules within the matrices, i.e., type I, two ethylene molecules in the cavity; and type II, one ethylene molecule in the cavity and the other one outside the cavity. CB[5] and CB[6] had a stable type II molecular conformation of ethylene, whereas CB[7] showed similar stability to type I and type II molecular conformations. For the first time, we demonstrated that CB[n]s (particularly CB[5]) are desirable gas storage and release systems for ethylene. This technology can enable precisely controlled and targeted applications of ethylene for food processing and agricultural applications.
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危险品化学品经营许可证（带存储）