APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Zhenlu Liu,Jing Xu,Caijin Xiang,Ye Liu,Lijun Ma,Linying Hu
Semiconductor materials can absorb visible light to become excellent hydrogen-producing materials. When different semiconductors are supported on each other, it can greatly promote the increase of hydrogen production rate. The article uses ZnS and CoMoO 4 to construct a new type of S-scheme heterojunction, and uses related characterization to illustrate the hydrogen production advantages and high performance reasons of the system. The experimental data of photocatalytic hydrogen production concretely proved the high catalytic performance of the composite material. The results shown that when the amount of ZnS loaded on CoMoO 4 was 5%, the adsorption of the composite catalyst and an appropriate amount of sensitizer made the hydrogen production rate reached 1233 μmol/g/h. This study used different characterizations to show the ball-and-stick structure of the composite catalyst and supplements the S-scheme heterojunction mechanism. Based on various studies, ZnS and CoMoO 4 had broad application prospects. The special electron transfer path of the S-scheme heterojunction provided theoretical model support for high-performance hydrogen production.
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JOURNAL OF MOLECULAR LIQUIDS
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2021
·
IF 6.165
Qiang Huang,Yu Tao,Huichang Li,Lihua Guo,Liye Wang,Chunlan Ban,Guopeng Shen
In this study, The solubility of (R,S)-mandelic acid in different solvents, including mono-solvent (H 2 O, methanol, ethanol, n-propanol, isopropanol) and binary solvents (methanol + H 2 O, ethanol + H 2 O, n-propanol + H 2 O, isopropanol + H 2 O, n-butanol + H 2 O), using analytical stirred-flask method and weight analysis method to determine the compositions of the saturated solutions at the atmospheric pressure. We found that the experimental solubility values increased with the rising of temperature accordingly. The experimental solubilities were correlated by the Ideal model, Apelblat model, λh (Buchowski) model, Wilson model, NRTL model. The results have shown that the Wilson model is the best model, which correlates the solubility of (R, S)-mandelic acid in the mono-solvent and binary solvents and fits well with experimental data. In addition, the thermodynamic properties of dissolution were calculated according to Van’t Hoff equation and experimental solubility, including Gibbs energy, entropy and enthalpy. The result confirms that the dissolution process in all solvents is always endothermic and entropy driven.
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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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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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JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 35
·16455-16469
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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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JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 16
·50263
·
IF 2.52
Shengsong Dai,Xuejun Yu,Rui Chen,Hong Zhou,Zhiquan Pan
An epoxy resin (EP) with excellent fire retardancy, good transparency, and satisfactory thermal stability has been obtained by introducing a new N/P/S containing flame retardant (HBD) into EP composites. When the phosphorus content was 0.48 wt%, EP/HBD reached V-0 rating with the limiting oxygen index of 33.5%. The cone calorimeter test (CC) indicated that the incorporation of HBD resulted in 1.5 times increase in ignition time, a 50% decrease in the maximum of heat release rates, 40% reduction of total heat release, and 50.7% decrease in total smoke production compared with EP. Besides, the fire-resistant behavior of EP/8% HBD is much better than the EP materials modified by similar P/N/S flame retardants reported in literature. The fire-retardant mechanism of HBD on EP was also analyzed by Raman, scanning electron microscope, Py-GC/MS, and Fourier transform infrared spectroscopy. The results show that HBD plays an important role in the formation of a dense intumescent carbon layer and gas phase quenching.
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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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JOURNAL OF POWER SOURCES
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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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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
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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