RSC Advances
·
2016
·Vol. 6
·期 16
·13371-13376
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IF 3.289
Yunshi Liu,Ping Yang,Jia Li,Katarzyna Matras-Postolek,Yunlong Yue,Baibiao Huang
SiO2@SnO2 core–shell nanofibers (NFs) were successfully prepared by single-spinneret electrospinning and subsequent calcination process. The precursor solutions were prepared from poly(vinylpyrrolidone), SnO2 precursors, and tetraethylorthosilicate (TEOS) with prehydrolysis. The prehydrolysis of TEOS plays an important role for the formation of core–shell structure. After calcining, the resulting fiber sample had an amorphous SiO2 core and a shell consisted of SnO2 particles. The fibers with various morphologies were obtained through adjusting the molar ratio of Sn and Si and the possible formation mechanism of core–shell NFs was proposed. Both Kirkendall effect and grain growth played important roles for the formation of core–shell structure. Furthermore, SiO2 was used as support material to fix the SnO2 particles and avoid the collapse of the SnO2 structure. The amount of SnO2 precursors directly determined the compactness of the shell, resulting in the different gas sensing properties. The SiO2@SnO2 core–shell NF network sensor responds to ethanol, ammonia, benzene, toluene, chloroform, and hexane gases, but it exhibited enhanced gas response to ethanol with a short response time. Those SnO2 particles formed on the exterior of the fibers provided lots of contact area with the target gas to reduce resistance. In addition, the connectivity between particles also had certain influence on the electrical conductivity of the sample. The results demonstrate that single-spinneret electrospinning can also be used to prepare core–shell fibers with various applications.
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ANALYTICAL SCIENCES
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2017
·Vol. 33
·期 2
·235-238
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IF 1.228
Xinchao BIAN,Zhiming CHEN,Lidong FENG,Bin SUN,Sheng XIANG,Yanlong LIU,Gao LI,Xuesi CHEN
An analytical method to determine the residual lactide in polylactide (PLA) was proposed using an internal standard method of gas chromatography (GC). PLA samples and diphenyl ether (DPE) as an internal standard were dissolved in dichloromethane, then PLA was precipitated in anhydrous alcohol. The residual lactide and DPE were extracted to alcohol for GC analysis. At room temperature, lactide could react with alcohol and change into ethyl lactoyl lactate (ELL), but the relative response factor of lactide versus DPE could be obtained through a numerical analysis method. Therefore, the residual lactide content could be quantitatively calculated in PLA. The relative standard deviation (RSD) of the measurements is not more than 7.0%, indicating that the method is suitably precise.
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JOURNAL OF FOOD AND DRUG ANALYSIS
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2016
·
IF 1.98
Ming-Chao Cui,Shao-Jun Chen,Han-Hua Wang,Zhao-Hui Li,Hong-Jiang Chen,Yong Chen,Hai-Bin Zhou,Xiang Li,Jian-Wei Chen
Thunberg fritillary bulb (the dry bulbs of Fritillaria thunbergii Miq.), a traditional Chinese Medicine, is widely applied as an expectorant and antitussive. In this investigation, the primary metabolites of bulbs, flowers, leaves, and stems of F. thunbergii were analyzed by gas chromatography–mass spectrometry. Principal component analysis, partial least squares-discriminate analysis, orthogonal projection to latent structures-discriminate analysis, and heat map analysis showed that there were dissimilar metabolites, and a negative correlation between amino acids and saccharides in different analytes. Furthermore, carbodiimide, tryptophan, glucose-6-phosphate, xylose, 2-piperidinecarboxylic acid, monoamidomalonic acid, phenylalanine, and histidine were found to play an important role in the plant metabolism net of F. thunbergii .
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CELLULOSE
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2017
·Vol. 25
·期 1
·463-471
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IF 3.417
Long Keying,Cha Ruitao,Zhang Yapei,Li Juanjuan,Ren Fangping,Jiang Xingyu
Cellulose nanocrystals (CNCs) of excellent mechanical properties, high purity, high aspect ratio, and cost-efficient production have drawn many attentions as a new class of reinforcement nanofillers. We chose CNCs as reinforcement nanofillers, which were incorporated in collagen to prepare CNCs/collagen casings by a traditional extruding method. The effects of CNCs on these casings were investigated. The dispersity and compatibility of CNCs within the collagen are rather good. The presence of CNCs can improve the light transmittance, barrier property, tensile strength, Young’s modulus, and thermostability of the CNCs/collagen casings, where collagen might cross-link with CNCs by electrostatic and hydrogen bonding interaction. When the CNCs content is 4 wt%, the water vapor permeability of CNCs/collagen casing reaches the minimum of 0.18 g·mm/h·m 2 ·KPa. That concentration gave the highest light transmittance, and the mechanical properties were optimal. The development of CNCs/collagen casings represents an important potential to extend shelf life by the prevention of lipid oxidation and water loss of sausages.
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RSC Advances
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2017
·Vol. 7
·期 78
·49777-49786
·
IF 3.108
Zanru Guo,Hongjian Gu,Wei Ma,Qiang Chen,Zhanfeng He,Jiali Zhang,Yongxin Liu,Longzhen Zheng,Yujun Feng
The design of controllable or “signal-triggered” metal nanoparticles is one of the emerging trends in nanotechnology and advanced materials. CO2-switchable polymer-hybrid silver nanoparticles (AgNPs) were prepared by a one-pot reaction reducing AgNO3 and trithioester terminated PDEAEMA with sodium borohydride (NaBH4). The hybrids showed a long-term stability, and their size and size distribution can be easily modulated by tuning the molar ratio of polymers to AgNO3. The hybrids not only exhibit hydrophobic–hydrophilic transitions in immiscible mixed solvents, but also undergo a switchable dispersion/aggregation states upon alternately treating with CO2 and N2. Moreover, this smart hybrid was preliminarily used as catalyst for the reduction of 4-nitrophenol. The catalytic activity of the hybrids can be switched and monotonously tuned by varying the flow rate of CO2 purged into the reaction system, which may open a new avenue for tailoring the catalytic activity of metal nanoparticles toward a given reaction.
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JOURNAL OF CHROMATOGRAPHY A
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2016
·
IF 3.926
Yunzhong Zheng,Meiling Qi,Ruonong Fu
This work presents the first example of utilization of graphitic carbon nitride (g-C 3 N 4 ) as stationary phase for capillary gas chromatographic (GC) separations. The statically coated g-C 3 N 4 column showed the column efficiencies of 3760 plates/m and weak polarity. Its resolving capability and retention behaviours were investigated by using the Grob test mixture, and mixtures of diverse types of analytes, and structural and positional isomers. The results showed superior separation performance of the g-C 3 N 4 stationary phase for some critical analytes and preferential retention for aromatic analytes. Specifically, it exhibited high-resolution capability for aromatic and aliphatic isomers such as methylnaphthalenes and dimethylnaphthalenes , phenanthrene and anthracene and alkane isomers. In addition, g-C 3 N 4 column showed excellent thermal stability up to 280 °C and good repeatability with relative standard deviation (RSD) values less than 0.09% for intra-day, below 0.23% for inter-day and in the range of 1.9–8.4% for between-column, respectively. The advantageous separation performance shows the potential of g-C 3 N 4 and related materials as stationary phase in GC and other separation technologies.
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JOURNAL OF CHROMATOGRAPHY A
·
2017
·
IF 3.981
Yunzhong Zheng,Qing Han,Meiling Qi,Liangti Qu
Seaweed-like graphitic carbon nitride (g-C 3 N 4 ) has a unique porous architecture composed of interlocking g-C 3 N 4 nanofibers (NF-C 3 N 4 ) with much higher surface area than bulk g-C 3 N 4 and shows good potential in separation science. This work investigated the separation performance of NF-C 3 N 4 as stationary phase for capillary gas chromatographic (GC) separations. The NF-C 3 N 4 column exhibits weak polarity and high column efficiency of 4728 plates/m for n -dodecane. Importantly, it displays good separation performance for a wide range of analytes and shows different retention behaviors from the bulk g-C 3 N 4 column and commercial HP-5MS column with 5% phenylpolysiloxane. Particularly, it shows high resolving capability for both aliphatic and aromatic isomers. In addition, NF-C 3 N 4 column has high thermal stability up to 280 °C and good separation repeatability with relative standard deviation (RSD) values in the range of 0.29–0.61% for intra-day, 0.56–1.1% for inter-day and 2.0–4.9% for between-column, respectively. Moreover, it was applied for the determination of isomer impurities in real samples, showing good potential in GC applications.
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JOURNAL OF ELECTRONIC MATERIALS
·
2016
·Vol. 46
·期 1
·363-369
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IF 1.491
Wang Xuesong,Li Haiying,Ni Mucui,Wang Lianyuan,Liu Li,Wang Han,Guo Xuexin
The ruptured Nd-doped In 2 O 3 porous nanotubes have been successfully synthesized by single-capillary electrospinning method. The morphologies of the as-prepared materials were characterized by scanning electron microscopy and transmission electron microscopy. It can be seen obviously that the surface of the nanotubes are distributed with cracks and pores, which formed such an open nanostructure. The crystal structures and components were determined by x-ray diffraction, energy-dispersive x-ray spectroscopy and x-ray photoelectron spectrometer. The gas-sensing properties of ruptured Nd-doped In 2 O 3 porous nanotubes were studied and the results show the excellent performances of the as-obtained materials. The response of ruptured Nd-doped In 2 O 3 porous nanotubes to 100 ppm of formaldehyde is 46.8 at the optimum temperature of 240°C. The response and recovery times are 8 s and 22 s, respectively. Furthermore, the lowest detection limit of formaldehyde is 100 ppb with the value of 2.4. In addition, the ruptured Nd-doped In 2 O 3 porous nanotubes exhibit good selectivity to formaldehyde and long-term stability.
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Surfaces and Interfaces
·
2025
·
IF 6.3
NiNa Ma,ShuYi Ma,JiaYun Guo,GeGe Fan,Ping Ni,YinYue Wang,JiaMin Zhu,Heng Wang
In this study, we engineered a triethylamine sensor that operates at low temperatures and is distinguished by its exceptional selectivity. The experiments specifically entailed synthesizing WO 3 nanostructured composites and SnWO 4 nanorod model materials through a direct hydrothermal approach. The superiority of composite samples over pure ones was established by evaluating their gas sensitivity through rigorous testing. Given the importance of accurately detecting trimethylamine gas in intricate environments, it is remarkable that only a limited number of sensors possess this capability. To tackle this problem, we have engineered a triethylamine sensor that exhibits strong resistance to interfering gases, delivering an outstandingly swift response time of 50 s and a recovery time of just 7 s. The composite sensor demonstrates remarkable sensitivity to 200 ppm of triethylamine gas, exhibiting a response that is 5.4 times more pronounced than that observed in the pure sample. The integration of WO3 notably decreases the optimal operating temperature of the SnWO 4 sensor from 240 °C to 130 °C, while also demonstrating a response value of 6.6 at reduced gas concentrations of 5ppm. Furthermore, the engineered gas-sensitive material demonstrates remarkable repeatability and enduring stability upon exposure to triethylamine. Further discussion delved into the gas sensing mechanism of the WO 3 /SnWO 4 gas sensor. In conclusion, this study presents a novel perspective on the sensitivity and selectivity of gas sensors, demonstrating extensive practical utility and significant application value.
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SENSORS AND ACTUATORS A-PHYSICAL
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2024
·
IF 4.1
Rongcai Jia,Liang Guo,Wei Yang,Dezhao Wang,Zhengzhe Li
Hydrogen sulfide (H 2 S) is a highly toxic gas commonly encountered in industrial settings, posing substantial health risks to workers. Therefore, the development of sensors with optimized operating temperatures, rapid detection speeds, and broad measurement ranges is of paramount engineering significance. In this study, ZnFe 2 O 4 /MoO 2 nanocomposites were synthesized using a hydrothermal method, and, for the first time, MEMS-based gas sensors utilizing ZnFe 2 O 4 /MoO 2 nanocomposite films were employed for hydrogen sulfide detection. The structural composition and morphology of the ZnFe 2 O 4 /MoO 2 (2:1) samples were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The gas sensitivity of ZnFe 2 O 4 /MoO 2 toward H₂S was systematically investigated. Gas sensitivity tests demonstrated that the ZnFe 2 O 4 /MoO 2 composite sensor exhibited a response value of 19.177 at 5 ppm hydrogen sulfide, which is 5.2 times greater than that of ZnFe 2 O 4 , the current dominant material for H₂S detection. Furthermore, the ZnFe 2 O 4 /MoO 2 composite sensor demonstrated a detection limit as low as 1 ppm and exhibited significantly faster response and recovery times (13 s and 11 s, respectively, for 5 ppm H₂S). The ZnFe 2 O 4 /MoO 2 (2:1) nanocomposite sensor exhibited excellent stability, sensitivity, and remarkable selectivity. This enhanced gas-sensing performance is attributed to the formation of n-n heterojunctions between ZnFe 2 O 4 and MoO 2 , as well as the optimized nanomorphology of the composite. Therefore, the ZnFe 2 O 4 /MoO 2 sensor presents a promising solution for hydrogen sulfide detection in industrial applications.
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INORGANIC CHEMISTRY COMMUNICATIONS
·
2024
·
IF 4.4
Diwei Deng,Ping Ma,Xianliang Li,Xiaoyu Chen,Yan Xu
Metal oxide heterostructures have been demonstrated excellent candidates acting as novel gas sensors with outstanding sensitivity and selectivity . In this work, a hierarchical NiGa 2 O 4 @C@CeO 2 heterostructure with corn-like NiGa 2 O 4 microcrystals covered by a thin carbon layer and then anchored with numerous amounts of external CeO 2 nanoparticles was prepared through the combination of hydrothermal and a subsequent calcination method. The NiGa 2 O 4 @C@CeO 2 composite demonstrates an excellent selective triethylamine (TEA) detection performance with a response of 11.1 towards 20 ppm TEA and a fast response/recovery time of 81 s/38 s. It also shows terrific selectivity for TEA when mixed with else interfering substances, along with prolonged reusability for at least 15 days. The enhanced TEA sensing performance can be ascribed to the significant improvement of conductivity and effective carrier transfer at the interface. This work provides a feasible method to fabricate metal oxide sensors with improved gas sensing performance.
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Small
·
2024
·
IF 13
Xue Hu,Zhiying Li,Jianbo Li,Chuanlong Jin,Junjiang Bao,Xiaopeng Zhang,Xiaobin Jiang,Ning Zhang,Gaohong He
Membrane technology exhibits low cost and high efficiency in gas separation. Zeolite-imidazole framework-67 (ZIF-67) membrane shows a theoretically superior performance in H 2 /CO 2 separation, owing to its effective size-sieving pores between H 2 and CO 2 . However, the gas molecules are permeate through a series of consecutive crystal cells of common ZIF-67 polycrystalline membranes, resulting in high transport resistance to the gas permselective transport. To this end, this work employs a contra-diffusion synthesis to construct a honeycomb ZIF-67 (h-ZIF67) crystalline membrane for low-resistance H 2 /CO 2 permselective transport. The controlled growth of h-ZIF67 following the van der Drift theory produces the honeycomb polycrystal with hierarchical channels for low-resistance gas permeation. The prepared membrane with micron-scale thickness still achieves a H 2 permeance as high as 1.6 × 10 −7 mol m −2 s −1 Pa −1 and a H 2 /CO 2 selectivity of 17, which can be maintained after a long-term operation for the H 2 /CO 2 mixture separation.
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