ACS Sustainable Chemistry & Engineering
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2024
·
IF 7.1
Yong Song,Zhiyuan Jin,Jiawei Zhang,Bo Jin,Rufang Peng
In this work, we report a novel spiral gas–solid two-phase flow (S-GSF) technique for the continuous mechanochemical synthesis of N-acylhydrazone derivatives. The synthesis of (E)-N′-(4-nitrobenzylidene)benzoylhydrazide (compound 1) was used as a model reaction to demonstrate the feasibility of this approach. The prepared products were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, ultraviolet–visible (UV–vis) spectroscopy, and scanning electron microscopy (SEM). Results showed that the product prepared by this method was analytically pure and had a high yield. No solvent was used in the reaction, and the byproduct water was in the form of water of crystallization. Moreover, SEM images showed that the method can directly obtain ultrafine powder products that are attractive to the pharmaceutical industry. Subsequently, kinetic analysis was performed by detecting the UV–vis spectra of the products under different optimized reaction conditions. The green chemistry metrics of the method showed that it is more environmentally friendly than the conventional solution method. In addition, the method was used in preparing a variety of N-acylhydrazone derivatives by using aldehydes with different substituents.
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FUEL
·
2024
·
IF 6.7
Ying Wang,Weiqi Zhang,Huiyuan Liu,Qian Xu,Lindiwe Khotseng,Yi Cheng,Huaneng Su
Ensuring consistent and reliable operation of proton exchange membrane fuel cells (PEMFCs) in low humidity environments is crucial for their real-world application. In this study, we introduce an innovative approach to address this challenge by employing a uniform growth of single crystal rutile titanium dioxide nanoarray (TiO 2 NRs) on the gas diffusion layer (GDL) through a seed coating hydrothermal method, which leads to the creation of a novel self-humidifying membrane electrode assembly (MEA). The effects of TiO 2 NRs on the wettability, resistance, performance and stability of the MEA were investigated, and the loading capacity was optimized. The results reveal that the integration of TiO 2 NRs into the MEA offers superior performance under 21 % relative humidity (RH) conditions compared to conventional doping TiO 2 nanoparticles into the catalyst layer (CL). By optimizing the TiO 2 NRs loading to 0.32 mg cm −2 of the MEA, a remarkable peak power density of 689.36 mW cm −2 was achieved at low humidity, equivalent to 93 % of the performance observed at 100 % RH. In addition, a 24-hour continuous test at constant voltage (0.6 V) showcased the exceptional stability of the TiO 2 NRs-based MEA, which is attributed to the unique water retention capabilities of the TiO 2 NRs within the CL, facilitating enhanced regulation of water balance within the PEMFC.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Shuaimei Li,Wenlei Zhang,Congwei Wang,Gang Li
Ethylene glycol (EG) is extensively utilized as anti-freezer and deicer, which would bring potential health risk under unintentional exposures especially with hazardous inhalation of EG aerosols or vapors. In this study, ZnIn 2 S 4 (ZIS)/WO 3 core-shell nanofibrous heterostructure loaded with optimized Au nanoparticles (NPs) was prepared for superiorly sensitive and selective EG gas sensing. The ternary Au/ZIS/WO 3 heterostructures exhibited an excellent response ( Ra/Rg =98.92) to 50 ppm EG, demonstrating an enhancement of 3.5 times compared to the binary ZIS/WO 3 , and a substantial improvement of 59.5 and 24.1 times compared to pure WO 3 and ZIS, respectively. The ternary Au/ZIS/WO 3 heterostructures also possessed an extremely low detection limit of 6 ppb, as well as excellent selectivity , repeatability, and long-term stability. This exceptional gas sensing performance can be attributed to its distinctive ternary Au/ZIS/WO 3 heterostructures with high specific surface areas . This unique structure not only facilitate the activation of abundant active oxygen species, but also promote the spillover effect of Au and enhance effective electronic distribution, thereby providing more EG adsorption sites, which was confirmed by density functional theory calculation. The synergistic effect arising from the metal-semiconductor interface and the core-shell heterostructure presents a novel avenue for advancing high-performance sensor technologies.
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ANALYTICAL CHEMISTRY
·
2012
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IF 5.856
Qianqian Xu,Baogen Su,Xinyi Luo,Huabin Xing,Zongbi Bao,Qiwei Yang,Yiwen Yang,Qilong Ren
Wall-coated open-tubular (WCOT) columns provide higher column efficiency and lower solute interfacial adsorption effect than packed columns. However, previous efforts used to measure the infinite dilution activity coefficient (γ∞) via a chromatographic technique have used packed columns, because the low carrier gas flow rate (U) and the small stationary phase amount (n2) in WCOT columns raise large errors. By rationally revising the γ∞-calculation equation for static-wall-coated open-tubular column, we observed that U and n2 are not necessarily needed and the resulting error could be reduced, and WCOT column gas chromatography subsequently became a superior method for the accurate γ∞ determination. In this study, we validate our revised γ∞-calculation equation by measuring γ∞ in an ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate system, in which 55 organic compounds covering a wide range of functional groups were used as probe solutes and their γ∞ values in the ionic liquid were determined at 40.0, 50.0, and 60.0 °C. Experimental error analysis shows that our revised equation remarkably reduces the error compared to the common γ∞-calculation equation. Our data is consistent with previously reported values obtained via other techniques, which further proves the credibility of our revised equation. The accurately determined γ∞ values can be directly used to calculate the partial molar excess enthalpy, selectivity, and capacity, which will benefit for the rapid screening of solvents (especially ionic liquids) in separation approaches.
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TALANTA
·
2012
·
IF 3.794
Lin Fan,Xiu-Ping Yan
Isostructural metal–organic frameworks (MOFs) MIL-100(Fe) and MIL-100(Cr), which have identical organic linker and Mobil Thirty-Nine zeolitic type, but different metal ions , were exploited as stationary phases for capillary gas chromatographic separation of alkane isomers. MIL-100(Fe) coated capillary column showed great capability and high efficiency for the gas chromatographic separation of alkane isomers without the need of temperature-programming, while MIL-100(Cr) coated capillary column gave poor performance for the separation. The separation performance of MIL-100(Fe) coated capillary column was even better than commercial HP-5MS and GS-GasPro capillary columns. The determined McReynolds constants, adsorption enthalpies and entropies showed that MIL-100(Fe) coated capillary column gave relatively weaker interaction with alkane isomers than MIL-100(Cr) coated capillary column. The relative standard deviations of repeatability for C7 alkane isomers on MIL-100(Fe) coated capillary column were 0.06–0.16%, 1.1–1.5%, 2.8–3.0% and 2.1–2.4% for retention time, half peak width, peak height and peak area, respectively.
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ANALYTICA CHIMICA ACTA
·
2024
·
IF 5.7
Shaojie Ma,Yuchen Zhu,Boxin Chen,Bin Zhao,Fei Feng
Background The micro gas chromatography column (μGCC) is one of the key components of the miniaturized gas chromatography system. However, light alkanes are difficult to be separated by a micro gas chromatography column , especially for methane and ethane, because the length of μGCC is limited by the area of a silicon substrate. More importantly, the heterogeneous microchannel surface formed by silicon glass bonding causes uneven stationary phase coating and the forces between the untreated microchannel surfaces and the stationary phase materials are weak, which will prevent the improvement of separation performance. Results In this paper, a micro gas chromatography column (μGCC) with uniform HKUST-1 stationary phase is reported. Significantly, an alumina film prepared by the atomic layer deposition (ALD) technique is used to homogenize the heterogeneous microchannels. The alumina is a hydrophilic material and the alumina made by the ALD technique is uniform. The forces between hydrophilic alumina film and HKUST-1 are strong, which can greatly improve the coating uniformity of the hydrophilic stationary phase HKUST-1. The test results show that the μGCC could baseline separate the light alkane mixtures (CH 4 , C 2 H 6 , C 3 H 8 , and C 4 H 10 ) at the high testing temperature of 120 °C. The maximum resolution of the difficult-separated methane and ethane reached 19.2, which is 108 % higher than the μGCC using the same stationary phase without homogenizing the microchannel inner surface. Significance The μGCC uses ALD alumina film to homogenize the microchannel inner surface; meanwhile, hydrophilic ALD alumina has a strong electrostatic attraction with the hydrophilic stationary phase HKUST-1. Homogeneous microchannel surface and strong electrostatic attraction are favorable to obtain uniform stationary phase which greatly improves the separation performance, resulting in a large resolution for methane and ethane. The μGCC has broad application prospects in light alkane separation.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
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IF 9
Yan Gao,Kangjia Sheng,Jiao Long,Junjie Yao,Tao Bao,Sicen Wang
Sample pretreatment prior to analysis is crucial for enhancing the quality of detection of target analytes. Herein, we propose a novel, easy-to-assemble continuous gas lift extraction device for the extraction of pharmaceutical pollutants. As a proof-of-concept, we assess the performance of the developed system through laboratory-scale experiments utilizing a homemade adsorbent. This device works by inserting an upright hollow cylindrical tube into the sample solution, with the upper end fitted with an air inlet and the lower end is equipped with a porous adsorbent. When gas is injected into the tube, the sample solution is circulated through the porous adsorbent driven by the pressure differential created by gas movement, thereby facilitating capture of target components within the sample solution. The adsorbent can be replaced based on the target molecule. We synthesize a type of porous adsorbent in the shape of a round cake, made from quartz sand that is surface-modified with a Zr-based metal–organic framework, using a solvothermal method. The experimental results indicate that the developed extraction method exhibits good performance with the limit of detections of 0.045–0.25 ng/mL, thereby demonstrating its potential for real-world applications.
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RSC Advances
·
2024
·Vol. 14
·期 17
·12225-12234
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IF 3.9
Zhixuan Wu,Zhengai Chen,Zhixiang Deng,Ning Dai,Yan Sun,Meiying Ge
In this work, a high-performance room-temperature ammonia (NH3) gas sensor based on Pt-modified WO3–TiO2 nanocrystals was synthesized via a two-step hydrothermal method. The structural properties were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The 10 at% Pt@WO3–TiO2 nanocrystals present the highest NH3 sensing performance at room temperature. Compared with the nanocrystals without Pt modification, the sensitivity of the Pt@WO3–TiO2 sensor is tenfold higher, with the lowest concentration threshold reaching the 75 ppb level. The response is approximately 92.28 to 50 ppm, and response and recovery times are 23 s and 8 s, respectively. The improved sensing was attributed to a synergetic mechanism involving the space charge layer effect and Pt metal sensitization, enhancing the electron transfer efficiency, oxygen vacancy and specific surface area. This study is expected to guide the development of high-performance room-temperature ammonia sensors for clinical breath testing.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2024
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IF 8
Hairui Fang,Hong Chen,Rong Tan,Lei Ge,Tingting Zhao,Haochen Wang,Shenglin Yuan,Dong Wang
Sulfur dioxide (SO 2 ) is a toxic and harmful decomposition product generated during arc discharge or partial discharge in sulfur hexafluoride (SF 6 ) electrical equipment, which can corrode internal pipelines. Detecting SO 2 is crucial for assessing the insulation condition of equipment and preventing faults. To overcome the challenges faced by traditional SO 2 gas sensors, including high operating temperatures, slow response times, and poor moisture resistance, this paper proposes a novel SO 2 gas sensor based on CuO/MoO 3 . The morphology, composition, and chemical states of the materials were analyzed using different characterization techniques. At 90°C, the S2 sensor (CuO: MoO 3 =1: 1) exhibited a fast response time (10 s) to 10 ppm SO 2 and demonstrated good moisture resistance (a 1 % change in relative humidity (RH) has the same effect on the sensor as 25.9 ppb SO 2 ). The response of the S2 sensor to 100 ppm SO 2 was 26.5. Additionally, the voltage sensitivity of the S2 sensor at low (1–10 ppm) and high (10–100 ppm) concentrations are 658.74 mV/ppm and 33.43 mV/ppm, respectively. Therefore, the S2 sensor is more suitable for low concentration conditions. These good sensing characteristics of the S2 sensor are owing to the high content of oxygen vacancies (39.2 %) and the heterojunction effect in the composite material. Additionally, this sensor exhibits excellent anti-interference capabilities, including moisture resistance and high selectivity. Therefore, the CuO/MoO 3 -based SO 2 gas sensor can be effectively applied to detect the decomposition of SF 6 .
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JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
·
2017
·Vol. 98
·期 4
·1574-1583
·
IF 2.463
Shanshan Yu,Yufan Zhang,Yun Ran,Wenyi Lai,Zhaoshou Ran,Jilin Xu,Chengxu Zhou,Xiaojun Yan
BACKGROUND Steryl glycosides (SGs) are sterol conjugates found in various plants, especially in those making up human diets. It has been demonstrated that SGs have potential health benefits, and they could be used as food supplements in a variety of food matrixes. Marine microalgae are a potential resource for human food and ingredients. In this study, gas chromatography–triple quadrupole mass spectrometry (GC–QQQ-MS) was used to characterize unknown SGs in eight microalgae belonging to different classes ( Isochrysis galbana 3011, Pavlova viridis , Platymonas helgolandica , Conticribra weissflogii , Thalassiosira pseudonana , Nitzschia closterium , Gymnodinium sp., and Karlodinum veneficum ). RESULTS The SGs were first extracted from lyophilized algae with chloroform–methanol, purified by solid-phase extraction and analyzed as trimethylsilyl derivatives. Nine SGs have been identified. In particular, new SGs like occelasteryl glycoside and stellasteryl glycoside were found in Gymnodinium sp., 24-methylene cholesteryl glycoside was detected in P. helgolandica , and 4,24-dimethylcholestan-3-yl glycoside was identified as the main constituent of microalga K. veneficum . The results also showed that the compositions of SGs in different microalgae varied, with a range of 5.234 to 0.036 g kg −1 , and microalga P. viridis contained the most abundant SGs. CONCLUSION GC–QQQ-MS is a powerful tool to detect SGs with different structures from a variety of microalgae. The compositions of SGs in different microalgae varied greatly. Microalgae are a good source of highly valued SGs. © 2017 Society of Chemical Industry
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
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IF 5.8
Xudong Li,Hongyan Zhang,Chu Chen,Haiyang Zhang,Chen Yang,Xiujuan Ma
A high-sensitivity NH 3 sensor based on gold nanoparticles or silver nanoparticles (AuNPs or AgNPs) modified ZnO (Au/ZnO or Ag/ZnO) was synthesized using hydrothermal method and the sensing mechanism was explained by density functional theory (DFT). Experimental results indicate that AuNPs or AgNPs modification can effectively improve the sensing characteristics of the ZnO-based NH 3 sensor, which is due to more hydroxyl groups, oxygen vacancies and oxygen free radicals on the surface of Au/ZnO or Ag/ZnO. The responses of AuZn2 and AgZn2 sensors to 1000 ppm NH 3 at room temperature are 7321.07 and 9329.79, which are 22.48 and 28.65 times higher than that of the ZnO sensor respectively. The low detection limits of the AuZn2 and AgZn2 sensors is 0.495 ppm and 0.405 ppm. The fast response/recovery times to 15 ppm NH 3 is 0.9 s / 0.9 s or 1.5 s / 0.9 s. DFT calculation results show that AuNPs or AgNPs on the ZnO surface make D-band center of ZnO moves to a higher energy level, which increases the chemical activity of AuZn2 or AgZn2, thereby improving the adsorption energy to NH 3 molecule. This work provides a new idea for high-performance NH 3 sensors fabrication and broadens the application field of ZnO materials.
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FUEL
·
2025
·
IF 7.5
Shuping Li,Cheng Dong,Xuan Qi,Shiyong Chen,Lixiao Shen,Yinning Zeng,Yan Li,Zhenxin Yi,Lin Zhang,Shunguan Zhu
A novel hollow-structured thermite, n-Al/H-MoO 3 , is designed to enhance the energy release mode and combustion performance of solid propellant. This research comprehensively explores the preparation and structural features of n-Al/H-MoO 3 within solid propellants. Furthermore, a series of rigorous combustion tests, performance assessments, and computational simulations are conducted to investigate its practical application. Experimental results indicate that the significant improvements in combustion performance have been observed by integrating this innovation n-Al/H-MoO 3 in solid propellants as a burning rate modifier. The heat of explosion increases to 6135 J·g −1 , a 41.76 % increase over the blank group (M0). Furthermore, its flame temperature is 494.3°C higher than that of the blank group. These substantial gains are primarily attributed to the unique hollow structure of n-Al/H-MoO 3 , which facilitates the reaction between H-MoO 3 and Al in the gaseous phase region, thereby improving combustion dynamics. The research findings offer theoretical foundations and experimental support for the design of more efficient and stable propellants.
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