MATERIALS LETTERS
·
2014
·
IF 2.269
Qingfei Wu,Jing Huang,Hua Li
Porous nanostructured WO 3 coatings were deposited by two routes, solution and suspension plasma spraying. The nanostructural characteristics of the coatings were tunable by adjusting the constituents of the starting liquid precursor and spray parameters. Planar or spherical WO 3 grains with controllable sizes in nano-scale have been fabricated. Complete formation of spherical WO 3 grains was attained during solution plasma spraying. Enhanced heating of the nano-WO 3 particles by augmenting plasma power gave rise to oriented WO 3 grain growth along (0 0 2) plane. The planar WO 3 grains with the dimension of ~50 nm, ~80 nm, and ~700 nm in thickness, width, and length respectively were fabricated by the suspension plasma spraying. The results provide clear insight into potential gas-sensing applications of the porous WO 3 coatings.
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ANALYTICAL CHEMISTRY
·
2014
·
IF 5.825
Jun-Hui Zhang,Sheng-Ming Xie,Mei Zhang,Min Zi,Pin-Gang He,Li-Ming Yuan
Chiral nematic mesoporous silica (CNMS) has attracted widespread attention due to some unique features, such as its nematic structure, chirality, large pore size, high temperature resistance, low cost, and ease of preparation. We first reported the use of CNMS as a stationary phase for capillary gas chromatography (GC). The CNMS-coated capillary column not only gives good selectivity for the separation of linear alkanes, aromatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and isomers but also offers excellent enantioselectivity for chiral compounds. Compared with enantioseparations on commercial β-DEX 120 and Chirasil-l-Val columns, a CNMS-coated capillary column offers excellent enantioselectivity, chiral recognition complementarity, and the separation of analytes within short elution times. It can also be potentially applied in high-temperature GC at more than 350 °C. This work indicates that CNMS could soon become very attractive for separations.
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Catalysis Science & Technology
·
2014
·Vol. 4
·期 5
·1286-1292
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IF 4.76
Bing Liu,Ting Huang,Zehui Zhang,Zheng Wang,Yuhua Zhang,Jinlin Li
The present study reported the results on the water–gas shift (WGS) reaction over a series of Ru/C catalysts. It was found that the reduction method showed a remarkable effect on the catalytic activity of Ru/C catalysts over WGS reaction, which increased in an order of the reduction by NaBH4, ethylene glycol, H2. It has been shown that alkali additives with K2CO3 significantly improved the activity of the Ru/C catalysts. XPS results indicated that Ru species were further oxidized by the addition of K2CO3, which indicated an electron transfer from the alkali metal to the substrate, resulting in stronger bonding of the adsorbed gas. FTIR results showed that the absorption peak intensity of H2O and hydroxyl group increased with the increase of K2CO3 content, due to the strong hygroscopic ability of K2CO3. Through the addition of K2CO3 to the Ru/C catalyst, much more water was adsorbed around the catalytic active sites, reducing the strong adsorption of CO on the active sites. Thus the addition of K2CO3 balanced the concentration of water and CO on the active sites, which was considered to be the key step for low temperature WGS reaction over Ru supported on irreducible activated carbon.
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FIBERS AND POLYMERS
·
2015
·Vol. 16
·期 10
·2130-2134
·
IF 0.881
Chen Yingbo,Wang Biao,Zhang Shifeng,Hu Xiaoyu,Cheng Bowen,Liu Dongqing,Zhang Yufeng
Cu-BTC/PVDF composite membranes were prepared by immersing PVDF hollow fiber supporting membranes into copper acetate aqueous solution and trimesic acid ethanol solution repeatedly. Surface and cross sectional morphologies of Cu-BTC crystals on the supporting PVDF membrane were investigated using SEM. Chemical composition and crystal structure of Cu-BTC were characterized by IR and XRD. Gas permeance and separation factor for CO 2 and N 2 of the Cu- BTC/PVDF composite membrane were recorded under different pressures. The results illustrated that with increasing reaction times, the crystal layer became more in density and less in defects, resulting in decrease of gas permeance and the separation mechanism changing from convective flow to Knusen diffusion.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2015
·
IF 2.912
Lei Xiang,Xiong-Ke Wang,Yan-Wen Li,Xian-Pei Huang,Xiao-Lian Wu,Hai-Ming Zhao,Hui Li,Quan-Ying Cai,Ce-Hui Mo
A reliable, sensitive, and cost-effective method was developed for determining three quaternary ammonium compounds (QACs) including dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, and didodecyldimethylammonium chloride in various vegetables using ultrasonic-assisted extraction and gas chromatography–mass spectrometry. The variety and acidity of extraction solvents, extraction times, and cleanup efficiency of sorbents were estimated to obtain an optimized procedure for extraction of the QACs in nine vegetable matrices. Excellent linearities (R2 > 0.992) were obtained for the analytes in the nine matrices. The limits of detection and quantitation were 0.7–6.0 and 2.3–20.0 μg/kg (dry weight, dw) in various matrices, respectively. The recoveries in the nine matrices ranged from 70.5% to 108.0% with relative standard deviations below 18.0%. The developed method was applied to determine the QACs in 27 vegetable samples collected from Guangzhou in southern China, showing very high detection frequency with a concentration of 23–180 μg/kg (dw).
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Scientific Reports
·
2015
·Vol. 5
·期 1
·1-6
·
IF 5.578
Yao Feng,Yi Bin,Shen Caihong,Tao Fei,Liu Yumin,Lin Zhixin,Xu Ping
Luzhoulaojiao liquor is a type of Chinese liquor that dates back hundreds of years, but whose precise chemical composition remains unknown. This paper describes the screening of the liquor and the identification of its compounds using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOF-MS). Samples were prepared by both liquid-liquid extraction and solid-phase microextraction, which facilitated the detection of thousands of compounds in the liquor, thus demonstrating the superior performance of the proposed method over those reported in previous studies. A total of 320 compounds were common to all 18 types of Luzhoulaojiao liquor studied here and 13 abundant and potentially bioactive compounds were further quantified. The results indicated that the high-performance method presented here is well suited for the detection and identification of compounds in liquors. This study also contributes to enriching our knowledge of the contents of Chinese liquors.
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RSC Advances
·
2015
·Vol. 5
·期 119
·98500-98507
·
IF 3.84
Yunshi Liu,Ping Yang,Jia Li,Katarzyna Matras-Postolek,Yunlong Yue,Baibiao Huang
SnO2 and SnO2/CeO2 one dimensional (1D) nanostructures with various morphologies including solid nanofibers (NFs), nanobelts (NBs), nanotubes (NTs), and wire-in-tubes (WTs) were successfully prepared via a single-spinneret electrospinning process and a subsequent heat-treatment by adjusting the heating rate and the amount of CeO2. The interesting morphology evolution of samples from NTs to NBs was reported with increasing amounts of CeO2. In addition, SnO2 particles existed on the surface of the CeO2 matrix to form diverse structures in the 1D nanofibers. The band gap of the composite oxides decreased with the addition of CeO2. Compared with other nanostructures, SnO2/CeO2 NTs exhibited superior gas sensing properties, such as the highest response to ethanol. Due to the existence of Ce3+ and oxygen vacancies and the hollow structure, SnO2/CeO2 NTs revealed great CO oxidation performance, indicating the enhanced interactions between the catalyst and the target gas. These excellent properties were attributed to the prominent 1D hollow morphology, the good dispersion of SnO2 nanoparticles on the surface of the CeO2 matrix, the ideal crystallinity, and the composite interactions between the two oxides. In addition, the current method could be utilizable to fabricate other metal oxides with various morphologies for property controlling and important applications.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2017
·
IF 2.536
Zhuomin Zhang,Yisen Zhan,Yichun Huang,Gongke Li
In this work, a portable large-volume constant-concentration (LVCC) sampling technique coupling with surface-enhanced Raman spectroscopy (SERS) was developed for the rapid on-site gas analysis based on suitable derivatization methods. LVCC sampling technique mainly consisted of a specially designed sampling cell including the rigid sample container and flexible sampling bag, and an absorption-derivatization module with a portable pump and a gas flowmeter. LVCC sampling technique allowed large, alterable and well-controlled sampling volume, which kept the concentration of gas target in headspace phase constant during the entire sampling process and made the sampling result more representative. Moreover, absorption and derivatization of gas target during LVCC sampling process were efficiently merged in one step using bromine-thiourea and OPA-NH 4 + strategy for ethylene and SO 2 respectively, which made LVCC sampling technique conveniently adapted to consequent SERS analysis. Finally, a new LVCC sampling-SERS method was developed and successfully applied for rapid analysis of trace ethylene and SO 2 from fruits. It was satisfied that trace ethylene and SO 2 from real fruit samples could be actually and accurately quantified by this method. The minor concentration fluctuations of ethylene and SO 2 during the entire LVCC sampling process were proved to be < 4.3% and 2.1% respectively. Good recoveries for ethylene and sulfur dioxide from fruit samples were achieved in range of 95.0–101% and 97.0–104% respectively. It is expected that portable LVCC sampling technique would pave the way for rapid on-site analysis of accurate concentrations of trace gas targets from real samples by SERS.
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RSC Advances
·
2017
·Vol. 7
·期 45
·28542-28547
·
IF 3.108
Jie Hu,Yongjiao Sun,Xiu Wang,Lin Chen,Wengdong Zhang,Yong Chen
Flower-like molybdenum oxide@tungsten oxide (MoO3@WO3) composite microstructures were successfully synthesized by hydrothermal and impregnation methods. The fabricated samples were characterized by XRD, EDS, SEM and TEM, and the results show that the MoO3@WO3 composite is composed of crystallized nanosheets with a thickness of about 40 nm. The gas sensing properties of the MoO3@WO3 composite microstructures towards hydrogen sulfide (H2S) were investigated as a function of operating temperature and gas concentration. The gas sensors based on MoO3@WO3 composites show better sensing performances than that of a pure one. Moreover, the Mo6W-based gas sensor exhibits the highest response (28.5 towards 10 ppm H2S), fast response/recovery time (2 s/5 s), low detection limit (20 ppb) and good selectivity at optimum operating temperature (250 °C). Such an excellent performance can be attributed to the heterojunction between MoO3 and WO3.
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JOURNAL OF CHROMATOGRAPHY A
·
2016
·
IF 3.926
Xiaohong Yang,Changxia Li,Meiling Qi,Liangti Qu
This work presents the separation performance of graphene-ZIF8 (G-Z) composite material as stationary phase for capillary gas chromatography (GC). The G-Z stationary phase achieved high column efficiency of 5000 plates/m determined by n -dodecane ( k = 1.22) at 120 °C and showed weakly polar nature. Importantly, it exhibited high selectivity and resolving capability for branched alkane isomers and aromatic positional isomers, showing clear advantages over the reported neat graphene and ZIF8. In addition, it attained high resolution for geometric cis -/ trans -isomers. The G-Z column exhibited good column thermal stability up to 300 °C and column repeatability with RSD values of retention times in the range of 0.01–0.19% for intra-day, 0.05–0.88% for inter-day and 0.66–5.6% for between-column, respectively, Moreover, the G-Z column was employed for the determination of minor impurity isomers in real reagent samples, which demonstrates its promising potential in GC applications .
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NANO
·
2016
·
IF 0.951
Zhiguo Sun,Jitao Yang,Li Zhang,Hongyong Xie
A new photocatalyst of sodium humate (HA–Na)/Nano-TiO 2 coating on the glass spheres for flue gas denitrification (DeNO x ) was prepared using the impregnation method. The HA–Na/TiO 2 is characterized by Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The photocatalytic activity of HA–Na/TiO 2 on removing NO x was investigated in a self-designed photocatalytic reactor. The synergistic mechanism of HA–Na and TiO 2 on DeNO x is also proposed and demonstrated. The experimental results indicate that specific surface area and average pore size of HA–Na are improved owing to the mixed TiO 2 nanoparticles. The crystal structure of TiO 2 has little change after mixing with HA–Na. Due to high photocatalytic performance of TiO 2 , NO was oxidized to NO 2 and HNO 3 eventually. On the other hand, HA–Na support can absorb and react with HNO 3 , which accelerates 10% of the catalytic reaction of TiO 2 and the utilization of light source. The chemical and physiological activity of oxidized HA–Na are improved than the original humate. The HA–Na/TiO 2 photocatalysts show great property on eliminating NO x because of the promoting effect between HA–Na and TiO 2 , and the NO removal efficiency can reach to 80% at the optimum condition.
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RSC Advances
·
2016
·Vol. 6
·期 55
·50138-50143
·
IF 3.289
D. Li,W. B. Li,J. S. Shi,F. W. Xin
Hexagonally packed mesoporous silica (HMS) was used as a kind of template-like material to prepare heteroatom doped porous carbons from the polymerization reactions of resorcinol and formaldehyde in the HMS pore channels. Different acids (HNO3, H2SO4, H3PO4) were used to catalyze the polymerization reactions to obtain N-doped, S-doped, and P-doped porous carbons, respectively. The adsorption properties of H2, CH4, and CO2 were investigated on these doped carbon materials systematically. For the hydrogen adsorption, the adsorption amount was 11.8%, 21.1%, and 33.3% higher on N-doped, S-doped, and P-doped porous carbons, respectively, than the carbon sample without doping, and the highest hydrogen uptake reached 14.88 mmol g−1 on the P-doped sample; regarding the CO2 adsorption, the adsorption amount reached 3.60 mmol g−1 and 3.16 mmol g−1 on the S-doped sample and N-doped sample, respectively, which is 39.5% and 22.5% higher than the sample without doping; it also shows that methane uptake amount was significantly increased by 27.1% on the S-doped sample as compared to the sample without doping, i.e., 3.52 mmol g−1 of CH4. Therefore, it is predicted that these doped carbon materials with high specific surface area are of great potential for the gas adsorption of H2, CH4, and CO2.
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