CHEMOSPHERE
·
2020
·
IF 5.778
Lin Dai,Jiaxin Xu,Jinbin Lin,Lingbin Wu,Huahua Cai,Jing Zou,Jun Ma
In this study, iodometric spectrophotometry , the most-used method for detecting peroxydisulfate (PDS), was modified by increasing the concentration of potassium iodide (KI) for realizing the immediate PDS determination and avoiding the interference of hydroxylamine. Kinetic studies showed that the reaction between PDS and I − to generate the yellow-colored I 3 − followed the kinetic equation as - d P D S d t = d I 3 - d t = 1 . 995 × 10 - 2 M - 2 · s - 1 · P D S 1 · I - 2 . Detection time of the iodometric spectrophotometry was shortened from 15 min to 15 s when KI concentration was increased from 0.6 M to 4.8 M. Different with the previous iodometric spectrophotometry, the modified method using 4.8 M KI as the indicator was well tolerable to the interference of hydroxylamine at acidic pH conditions. The calibration curve of the modified method showed a well linear relationship (R 2 = 0.999) between the absorbance of I 3 − at 352 nm and PDS concentration in the range of 0–80 μM. The modified method was highly sensitive with the absorptivity of 2.5 × 10 4 M −1 cm −1 and the limit of detection of 0.11 μM. Moreover, the modified method was successfully applied for monitoring the change of PDS concentration during the degradation of diclofenac with four different PDS-based AOPs , the calculated reaction stoichiometric efficiency ( R S E ( % ) = D i c l o f e n a c d e g r a d e d P D S c o n s u m e d × 100 % ) followed the order as heat/PDS system > hydroxylamine/Fe 2+ /PDS system > hydroxylamine/Cu 2+ /PDS system > Fe 2+ /PDS system.
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PubMed
高影响因子
ACS Catalysis
·
2020
·
IF 12.35
Zhou Zhang,Wengang Liu,Yuanyuan Zhang,Jingwen Bai,Jian Liu
Herein, taking inspirations from metalloenzymes, we constructed atomically dispersed manganese sites anchored onto conjugated tri-s-triazine units of graphitic carbon nitride as a bioinspired photocatalyst (Mn1/tri-CN) for the oxo-dehydrogenation of N-heterocycles. The primary coordination sphere of atomic Mn-N2 sites (role i: oxygen activation) as well as the π–π stacking interactions between tri-s-triazine units and substrate mimicking the secondary coordination sphere (role ii: substrate adsorption) synergistically realized high-efficiency electron transfer/utilization in photocatalytic oxidation reactions, as was demonstrated experimentally and theoretically. The Mn1/tri-CN catalyst exhibited impressive oxo-dehydrogenation activity and selectivity toward a broad scope of N-heterocycles in an air atmosphere. The current work suggests that simultaneously engineering the metal active sites of catalysts and the adaptive local environment of the matrix may open an avenue for the synthesis of fine chemicals.
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POLYMERS FOR ADVANCED TECHNOLOGIES
·
2020
·Vol. 32
·期 4
·1604-1614
·
IF 2.578
Gang Zhang,Dongdong Song,Su Ma,Yanlin Wang,Xiaotian Xie,Yanmao Dong
Currently, the issue of improving the flame-retardant performance of unsaturated polyester resin (UPR) has drawn a lot of attention. In this study, methyl vinyl di (1-thio-2,6,7-trioxal-1-phosphabicyclo [2.2] octane-4-methoxy) silane (MVDOS) with P-N-Si-based cage unit was synthesized, and it was utilized as a reactive flame-retardant monomer to modify UPR. The UPR/MVDOS composites were prepared by introducing different ratios of MVDOS into UPR via the reaction of crosslink. The efficiency of the resulted composites was investigated by using the limiting oxygen index (LOI), vertical burning test, and cone calorimeter test. The results showed that the composites reached the V-0 rate without dripping, and the LOI value was 29.1% when the content of MVDOS was as low as 18 wt%. Cone calorimeter tests revealed the peak of heat release and CO production of UPR/MVDOS-18 were 238.2 KW/m 2 and 0.0167 g/s, which were respectively lower than the ones of neat UPR. The introduction of MVDOS also increased the stability of UPR composites. Furthermore, the scattering electron microscopy, laser Raman spectroscopy, and X-ray photoelectron spectroscopy studies revealed that the incorporation of MVDOS stimulated the UPR matrix to generate char layer with increased graphitization degree, which provided a good barrier to prevent heat and oxygen from being transferred and then protected the materials inside from further burning. This research provides a new way to obtain flame-retardant UPR composites with high performance.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 35
·16455-16469
·
IF 3.553
Zhang Zengqi,Wang Qiang,Zhang Mingzhong,Huang Zongxian,Zhuang Shiyu
The filler effect is the most important physical mechanism of mineral admixtures in the early hydration of cement whose chemical properties greatly affect the precipitation of C–S–H. In this study, calcite, strontianite, magnesite, dolomite, quartz, whewellite and whitlockite were selected as the fillers. The morphology and reaction kinetics of synthetic C–S–H precipitated on the surfaces of different fillers were studied via electron microscopy observations and electrical conductivity and ion concentration measurements. The precipitation rate of C–S–H has a positive correlation with the affinity of Ca 2+ for adsorption on the fillers, which can be explained by the nucleation barrier of C–S–H. Extremely ordered honeycomb-like morphology of the C–S–H is found on calcite and strontianite surfaces, while less regular leaf-like or honeycomb-like C–S–H is found on whewellite and whitlockite. The ordered C–S–H pattern is related to the lattice cleavage of the ionic compound filler. In the case of quartz, C–S–H prefers growth along the tangential direction, which is quite different from the normal-direction growth on ionic compounds. The in-plane growth of C–S–H on quartz is believed to be induced by a layer of loosely physically adsorbed Ca 2+ .
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Polymer Chemistry
·
2020
·Vol. 11
·期 11
·1937-1946
·
IF 5.342
Yang Jiao,Guofei Chen,Nafeesa Mushtaq,Haijun Zhou,Xiaoqi Chen,Yantao Li,Xingzhong Fang
Two isomeric diamine monomers, 2-(3-aminophenyl)benzo[d]oxazol-5-amine (2a) and 2-(3-aminophenyl)benzo[d]oxazol-6-amine (2b), were designed and synthesized. The corresponding novel series of poly(benzoxazole imide)s (PBOPIs) were prepared with commercial tetracarboxylic dianhydrides via thermal imidization. These series of PBOPIs showed great Tgs ranging from 285 to 363 °C, excellent thermal stability when performed at 5% weight loss temperatures (Td5%s) of 510–564 °C in N2 and good mechanical properties (tensile strengths of 103–126 MPa, tensile moduli of 2.9–3.7 GPa and elongations at break of 3.0–6.5%). Furthermore, controlled molecular weight (Mw) polymers PI-3a-PA and PI-3b-PA derived from 4,4′-oxydiphthalic anhydride (ODPA) with 2a and 2b demonstrated good melt processability with minimum complex viscosities of 2258 and 3444 Pa·s at 420 °C and low melt viscosity ratios of 1.29 and 1.93 at 400 °C, respectively. The PI-b series showed higher Tg & Td5% and lower transparency compared with the PI-a series due to the isomeric effect.
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PHYSIOLOGICAL AND MOLECULAR PLANT PATHOLOGY
·
2020
·
IF 1.646
Yan Jin Gao,Wei Jie Fu,Jia Liu,Yi Juan Chen,Guang Hui Dai
Cucumber powdery mildew (PM) is a destructive fungal disease which has a substantial impact on cucumber yield and quality. Our previous work has demonstrated that (+)-( S )-ar-turmerone (ATM) is an effective compound for controlling PM infected by Podosphaera xanthii in cucumber. In this study, the effect of ATM on cucumber PM was histologically investigated by observations on the morphology of the pathogenic fungus at different time points after inoculation. It was found that the ATM caused the collapse of the pathogen's conidia and mycelia structure, the cytoplasm coagulation, the reduction of the conidia germination rate, and the inhibition of the conidiophore growth, therefore, prevented the re-infection of the P. xanthii . Evaluation of the content of total phenols and flavonoids in cucumber ATM-treated leaves showed that the ATM-treatment could increase the content of total phenols and flavonoids in cucumber leaves significantly in comparison to the control. A further analysis of the contents of the compounds showed that ATM-treatment could increase the content of rutin , quercetin , hesperetin , and gallic acid , syringic acid , vanillic acid and salicylic acid. Meanwhile, the activity of phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) in cucumber leaves were increased slightly, but the activity of peroxidase (POD) and superoxide dismutase (SOD) were significantly increased through ATM treatment. It should be estimated from this study that the ATM not only directly affected the growth of P. xanthii but also enhanced the cucumber plant resistance to the disease.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Yanqiao Xu,Ting Chen,Zhixiang Xie,Weihui Jiang,Lianjun Wang,Wan Jiang,Xiaojun Zhang
Understanding the surface characteristic-optical property relationship of Cu-In-Zn-S (CIZS) quantum dots (QDs) is necessary for tuning the optoelectronic performances, and the photoluminescence quantum yields (PLQYs) of CIZS QDs prepared in aqueous solution are still relative low compared with that of obtained in organic phase, which seriously restricts their applications. Herein, an efficient method was proposed to prepare CIZS/ZnS/PVP composites and their application in white light-emitting diodes (WLEDs) was investigated. CIZS QDs were synthesized through hydrothermal process with the assistance of ionic liquid (IL), which could enhance the PL performance and reduce the reaction time simultaneously. The effects of hydrothermal temperature and time on the phase composition, morphology, and optical properties of CIZS QDs were systematically investigated. The results showed that the BF 4 − anion played a crucial role in boosting the emission property of CIZS QDs owing to the effective reduction of dangling bonds on the surface of QDs, which induced by the corrosion of F − deriving from the decomposition of BF 4 − . The surface modulation led to the improvement of PLQY from 6.2% to 8.4%. In addition, the PLQY of QDs was further improved to 31.2% by coating with ZnS shell around CIZS cores. Furthermore, highly luminescent CIZS/ZnS/PVP composites were prepared to eliminate the aggregation-induced fluorescence quenching effect, which was beneficial to the application in WLEDs. Consequently, a WLED achieved the color rending index (CRI) of 87.2, correlated color temperature (CCT) of 4977 K, and luminous efficacy (LE) of 90.11 lm/W by using the orange-yellow CIZS/ZnS/PVP composites and green Lu 3 Al 5 O 12 :Ce 3+ phosphors as the color conversion layer, suggesting the potential for solid state lighting application.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2020
·
IF 7.1
Songlin Liu,Hao Ma,Jinyu Zhu,Xiao Xia Han,Bing Zhao
Protein S-nitrosylation is an important post-translational modification, which has important effect on protein functions and is relevant to various diseases. For quantification of the S-nitrosated proteins, it is still challenging to establish a detection method in combination of fast and one-step determination, highly sensitivity and accuracy. Here, we develop a label-free, direct detection method for S-nitrosated proteins based on resonance Raman scattering of ferrous cytochrome c. The laser source of the Raman spectrometer is utilized both for inducing NO leakage and for Raman scattering excitation. The heme ligation alteration and oxidation enable fast quantification of the released NO by the resonance Raman spectroscopy of the cytochrome c. All the results shown in this study demonstrate the great potential of the proposed method for fast, sensitive and reliable assessment of total S-nitrosated proteins in the clinical applications.
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Catalysis Science & Technology
·
2020
·Vol. 10
·期 5
·1368-1375
·
IF 5.721
Cankun Jiang,Lulu Zhang,Fan Gao,Xueyan Huang,Rui Lei,Yun Ye,Jie Yuan,Ping Liu
A CdS@MoOx core–shell nanorod photocatalyst has been constructed by a one-step in situ photodeposition method, which effectively utilizes the photoproduced-hole-induced dehydration and condensation of Mo–O–H derived from the hydrolyzed product of MoCl5, to successfully deposit a layer of MoOx on the surface of CdS NRs. X-ray photoelectron spectroscopy further confirmed that S–Mo bonds serve as bridges for carrier transport between the core and the shell, significantly reducing the interface impedance and improving the carrier transmission efficiency. Due to the superior interfacial carrier separation as well as the enhanced light absorption, the optimal CdS@MoOx-0.9 nanocomposite exhibits a high hydrogen production performance (5.42 mmol g−1 h−1) under visible light irradiation (λ > 400 nm). We have experimentally shed light on the mechanism of this excellent enhancement performance in detail. Moreover, our work can broaden the range of construction and application of developing other photocatalytic materials containing transition metal oxides.
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CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Rui Wang,Jing Li,Ying Zhang,Pengyu Li,Jidong Duan,Manqin Tang,Chun Yuan
Li–S battery is considered as one of the most competitive energy storage devices mainly due to the high theoretical specific capacity and high specific energy. However, when facing with the practical application, some issues, especially poor electro-conductivity of element sulfur and severe polysulfides (LiPSs) migration, are still needed to solve to further improve the performance of the Li–S batteries. Aiming at the above two disadvantages, in this work, multifunctional separators are designed as efficient LiPSs absorber via coating vapor grown carbon fiber/MoS 2 (VGCF/MoS 2 ) composites on the polypropylene separator (PP) near the cathode side. For the as-prepared VGCF/MoS 2 coated polypropylene separator (VM/PP), MoS 2 could provide strong chemical adsorption for the LiPSs, while the VGCF framework could act as an electronic transmission channel for the conversion of LiPSs, and also provide physical adsorption for LiPSs at the same time. Benefit from these characteristics, the batteries with VM/PP exhibits a high initial capacity of 1208.7 mAh g −1 at 0.2C and maintains at 862.4 mAh g −1 after 200 cycles. Impressively, the VM/PP shows the high specific capacity of 904.3 mAh g −1 and long-lasting cycling stability with 0.03% capacity attenuation per cycle over 600 cycles at 1.0C, demonstrating excellent electrochemical performance.
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Nanoscale Advances
·
2020
·Vol. 2
·期 8
·3334-3340
·
IF 0
Jieyu Xu,Lin Ge,Yajun Zhou,Guangyu Jiang,Liang Li,Yunheng Li,Yongsheng Li
Heteroatom doping has been proved to be an effective strategy to optimize the activity of hydrogen evolution reaction (HER) catalysts. Herein, we report N, P, S multi-doped Mo2C/C composites exhibiting highly efficient HER performance in acidic solution, which are facilely fabricated via annealing of N, P, S-containing MoOx–polyaniline (MoOx–PANI) hybrid precursors. The optimized N, P, S multi-doped Mo2C/C catalyst with a moderate P dopant level (NPS-Mo2C/C-0.5) exhibits excellent performance with an overpotential of 53 mV to achieve a current density of 20 mA cm−2, a Tafel slope of 72 mV dec−1 and good stability in acidic electrolytes. Based on the study of XPS, EPR and 31P MAS NMR, the excellent electrocatalytic performance could be attributed to the effective electronic configuration modulation of both Mo2C nanorods and the carbon matrix, derived from stronger synergistic N, P, S multi-doping coupling effects. This work provides a promising methodology for the design and fabrication of multi-doped transition metal based electrocatalysts via electronic structure engineering.
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PubMed
JOURNAL OF POWER SOURCES
·
2020
·
IF 8.247
Xinan Shi,Lijian Huang,Daocheng Pan
In this research, a facile and environmentally friendly solution approach is developed to deposit Cu 2 ZnSn(S,Se) 4 thin films by addition of n -butylammonium butyrate ionic liquid . n -Butylammonium butyrate plays a critical role in solution deposition of Cu 2 ZnSnS 4 precursor thin film. We find that liquid n -butylammonium butyrate can dissolve a number of metal oxides , including Cu 2 O, ZnO, and SnO as well as various metal chlorides , metal nitrates and metal acetates. Smell-free Cu 2 ZnSnS 4 precursor solution is synthesized by dissolving Cu 2 O, ZnO, SnCl 2 and thiourea in an ethanol solution of n -butylammonium butyrate. Thermally degradable n -butylammonium butyrate can be completely removed by a low-temperature sintering process , forming high quality Cu 2 ZnSnS 4 nanoparticle thin film. A power conversion efficiency of 8.79% is obtained by this facile and green solution approach.
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