CHEMOSPHERE
·
2020
·
IF 5.778
Zijun Pang,Yajuan Cai,Weihao Xiong,Junyang Xiao,Jing Zou
A new spectrophotometric method for measuring permanganate index (chemical oxygen demand using potassium permanganate (KMnO 4 ) as oxidant, COD Mn ) in water was established. The method was based on the rapid oxidation of N,N -diethyl- p -phenylenediamine (DPD) by residual KMnO 4 in digestion solution under neutral pH condition to form the stable pink radical (DPD ●+ ). Only 20 s were enough to form the pink DPD ●+ . The generated DPD ●+ could be quantitatively measured by a visible spectrophotometer at 551 nm. Stoichiometric coefficient of the reaction between KMnO 4 and DPD was close to 1:5 (1:5.07). There was a well linear relationship (R 2 = 0.999) between the change of the absorbance of DPD ●+ at 551 nm and the concentration of COD Mn in the range of 0–4.46 mg L −1 . Limit of detection of the DPD method was as low as 0.02 mg L −1 COD Mn . The DPD method was highly accurate for measuring COD Mn in standard solutions with well recovery rates of 99.17%–102.22%, and was well tolerant to the interference of coexistent Cl − and Fe 3+ . The DPD method was successfully applied for measuring COD Mn in real water samples, including surface water, underground water and drinking water . In comparison to the traditional titration method, the proposed DPD method was more convenient to operate, required less samples and digestion reagents (i.e., KMnO 4 and H 2 SO 4 ) and could be employed for online monitor.
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PubMed
高影响因子
RARE METALS
·
2020
·Vol. 40
·期 6
·1571-1577
·
IF 2.161
Zhu Meng-Ya,He Ping,Yang Xue-Li,Hui Guang-Ze,Tang Cheng-Chun,Pan Guo-Feng,Bie Li-Jian
Abstract P-xylene (p-C 8 H 10 ) is extremely harmful and dangerous to human health due to high toxicity and strong carcinogenicity. Exploring sensitive material to effectively detect p-xylene is of importance. In this paper, perovskite single crystal (C 4 H 9 NH 3 ) 2 PbI 4 has been successfully synthesized via solution method. The obtained product was analyzed by single crystal X-ray diffraction. With the space group Pbca, orthorhombic (C 4 H 9 NH 3 ) 2 PbI 4 layered perovskite structure consists of an extended two-dimensional network of corner-sharing PbI 6 octahedron. Single layer perovskite sheets of distorted PbI 6 octahedron alternated with protonated n-butylammonium cation bilayers, which offers many advantages and provides the possibility of forming a gas sensor device based on the change of resistances. Density functional theory (DFT) simulations regarding the adsorption energy revealed that this organic–inorganic hybrid perovskite compound has excellent selectivity toward p-xylene compared with other gases including C 2 H 5 OH, C 6 H 6 , CH 2 Cl 2 , HCHO, CH 3 COCH 3 and C 7 H 8 . The calculation of electron density, density of states and electron density difference showed the sensing mechanism of p-C 8 H 10 is mainly derived from physical adsorption–desorption in view of electron transfer. Graphic abstract For organic–inorganic hybrid perovskite (C 4 H 9 NH 3 ) 2 PbI 4 , single layer perovskite sheets of distorted PbI 6 octahedron alternated with protonated n-butylammonium cation bilayers (a), which offers many advantages and provides the possibility of forming a gas sensor device based on the change of resistances. Electron density difference calculation shows that adsorption of p-xylene molecule has an obvious effect on the electron distribution of (C 4 H 9 NH 3 ) 2 PbI 4 , results in electrically polarization as a local manner (b).
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 6
·3120-3127
·
IF 3.591
Yixuan Huang,Liyan Xie,Kangji Zhuo,Hao Zhou,Yanhui Zhang
MIL-101(Fe)-based composite materials and their application for the generation of H2 by the catalytic reduction of nitro organics are reported in this study. NaBH4 and water contribute hydrogen for the catalytic reduction of nitro organics, but the possibility of nitro organics as a potential hydrogen source is often overlooked due to the simplicity of the reaction. However, experiments have revealed that the reaction process is accompanied by the production of H2, which is affected by the concentration of nitro organics. Moreover, the reaction is more conducive to the generation of H2 compared to NaBH4 hydrolysis under the same conditions. Unlike specially catalyzing the expensive NaBH4 hydrolysis, hydrogen is a by-product of the reduction of pollutants by inexpensive catalysts (NaBH4 acted as an electron donor for the catalyst). Accordingly, the reaction mechanism of p-nitrophenol hydride reduction was optimized. This work provides a new perspective on the application of this reaction.
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高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2020
·Vol. 34
·期 11
·e5932
·
IF 3.14
Yanming Jia,Junwen Wang,Kan Zhang,Chuanmin Ding
A highly shape-selective and relatively long-lifetime HZSM-5-based catalyst (Zn-2P/HZSM-5) was prepared by chemical modification with both ZnSiF 6 ·6H 2 O and H 3 PO 4 solution. The phosphoric acid modification could effectively modulate the Brønsted acid strength of the HZSM-5 catalyst, which promotes the oligomerization, alkylation, cyclization, and hydrogen transfer reactions. The introduction of Zn-Lewis acid sites significantly improved the dehydroaromatization of higher olefins. All of these were very beneficial for the generation of BTX (i.e. b enzene, t oluene, and x ylene) hydrocarbons in aromatization of methanol. The coke amount and the average rate of coke formation decreased over the Zn-2P/HZSM-5 catalysts, which may largely be ascribed to its lower strong acid sites and lower outer surface acidity. The catalytic performance of methanol aromatization showed that the Zn-2P/HZSM-5 catalyst exhibited the highest BTX selectivity of about 46.76% and the longest catalytic lifetime of about 498 h at T = 400 °C, P = 0.1 MPa, and weight hourly space velocity = 0.7 h −1 .
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高影响因子
TALANTA
·
2020
·
IF 5.339
Na An,Quan-Fei Zhu,Lei Yu,Yong-Ting Chen,Sheng-Li Chen,Yu-Qi Feng
In this study, a derivatization-assisted pseudo -multiple reaction monitoring with high CID voltage (HV- p -MRM) strategy was proposed for the analysis of brassinosteroids (BRs) by liquid chromatography-triple quadrupole mass spectrometry (LC-QqQ MS). The concept of the HV- p -MRM strategy was proposed on the basis of an assumption that the precursor ion of analyte is stable in collision cell and less prone to fragmentation at high CID voltage, while co-existing ions (impurity) of easy fragmentation can break down into smaller fragment ions. In such case, by increasing the CID voltage, the co-existing ions that are introduced due to the low resolution of the quadrupole 1 (Q1) can be filtered out by quadrupole 3 (Q3), while the stable precursor ion of analyte will pass through Q3, thereby that the signal-to-noise ratio (S/N) of the analysis can be improved. As a proof-of-concept study, BRs were derivatized with rhodamine B-boronic acid (RhB-BA) and then the derivatives were used to investigate their variations in MS signal, background noise, and S/N upon the CID voltage and MS scanning resolution. The results showed that S/N of these derivatives can be improved in HV- p -MRM mode. To further demonstrate the feasibility of HV- p -MRM strategy, a RhB-BA derivatization assisted LC-HV- p -MRM-MS method was developed for the analysis of BRs. Using this method, rapid and sensitive determination of BRs in different organs of rape flower was achieved. It can be expected that HV- p -MRM may be suitable for the analytes that are stable or can be converted into compounds of high stability in collision cell at high CID voltage.
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高影响因子
COLLOID AND POLYMER SCIENCE
·
2020
·Vol. 298
·期 6
·629-636
·
IF 1.536
Yang Xu,Li Wenbo,Sun Zhaojie,Yang Chunhui,Tang Dongyan
In this work, pH/temperature dual-sensitive polymers of P(NVCL-co-MAA) with the increased low critical solution temperature (LCST) values of about 37 °C that differed from that of ~ 32 °C of pure poly(N-vinyl caprolactam) (PNVCL) were synthesized via radical polymerization. Then the nanofibers of P(NVCL-co-MAA) and its cospinned nanofibers with nifedipine (NIF) as drug model were fabricated by electrospinning method. Structures and the interactions within the components were detected by FT-IR, NMR, and XPS methods. The dual-responsive properties and the controlling release of the drug were investigated by water contact angle tests and in vitro drug release tested by UV-vis spectrophotometer. SEM was conducted to demonstrate the morphology of the nanofibers and the obvious improved stabilized morphology of the modified system within the aqueous media. The maintained morphology within the media and the obvious elongated releasing period of over 150 min at 37 °C and with pH of 1.99 both proved the promising prospects of the fabricated nanofibers as excellent carrier in drug delivery system.
Graphical abstract
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高影响因子
INORGANIC CHEMISTRY
·
2020
·
IF 4.825
Haonan Liu,Hongping Wu,Hongwei Yu,Zhanggui Hu,Jiyang Wang,Yicheng Wu
Mo(VI)-containing phosphates are widely used in catalyses, ion batteries, and nonlinear optical (NLO) crystals. However, few strategies can effectively guide the syntheses of the Mo(VI)-containing phosphates. In this paper, three new Mo(VI)-containing phosphates, Cs3Mo12PO40, LiK(MoPO6)2, and Sr(MoPO6)2, with different dimensions have been successfully synthesized by adjusting the Mo/P ratios. Interestingly, Cs3Mo12PO40 is a classic Keggin-type polyoxometalate composed of zero-dimensional (0D) [Mo12PO40]3– clusters, whereas LiK(MoPO6)2 and Sr(MoPO6)2 have three-dimensional (3D) [MoO2O4P]∞ frameworks consisting of MoO6 octahedra and PO4 tetrahedra in a 1/1 ratio. Detailed structural comparisons of Mo(VI)-containig phosphates indicate that the Mo/P ratios have a significant effect on the structural dimensions. Further, the optical properties and thermal stabilities of Cs3Mo12PO40, LiK(MoPO6)2, and Sr(MoPO6)2 are also determined.
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高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2020
·
IF 3.333
Xin Hu,Ning Li,Tingting Heng,Liang Fang,Chunhua Lu
An efficient graft modification strategy was developed based on photo-induced organocatalyzed atom transfer radical polymerization (O-ATRP) for the functionalization of poly(vinylidene fluoride) (PVDF) based copolymer . P -anisaldehyde was served as an organic photoredox catalyst to mediated O-ATRP of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) in the presence of poly(vinylidene fluoride- co -chlorotrifluoroethylene) (P(VDF- co -CTFE)) as the macroinitiator under UV irradiation . Excellent temporal control and low catalyst concentration was achieved. Chain extension confirmed the chlorine atom attached to the graft polymer chain end. Metal-free P(VDF- co -CTFE)- g -PMMA and P(VDF- co -CTFE)- g -PGMA with varied graft contents were obtained, which would find potential applications in dielectric materials .
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高影响因子
Nanoscale
·
2020
·Vol. 12
·期 27
·14863-14869
·
IF 6.895
Shuli Yin,You Xu,Songliang Liu,Hongjie Yu,Ziqiang Wang,Xiaonian Li,Liang Wang,Hongjing Wang
The development of doped noble metal catalysts with nonmetal elements to improve the catalytic performance toward the oxygen reduction reaction (ORR) is significant for proton exchange membrane fuel cell technology. Here, we report a one-pot for dual-nonmetal-doping strategy for the synthesis of S and P-co-doped mesoporous PtPd nanocages (PtPdSP mNCs) by using pre-synthesized mesoporous PtPd nanocages (PtPd mNCs) as the precursor and triphenylphosphine sulphide as both S and P sources. Benefitting from the combined advantages of metal–nonmetal incorporation, hollow cavity and surface porosity, the resultant quaternary PtPdSP mNCs exhibit outstanding ORR activity and long-term stability. This research work provides a good strategy for the doping of two or more selected nonmetallic elements into metallic nanocrystals with a controllable structure and composition.
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高影响因子
JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY
·
2020
·Vol. 97
·期 3
·289-300
·
IF 1.659
Hardy Z. Castada,Zhaoyu Sun,Sheryl A. Barringer,Xuesong Huang
p -Hydroxybenzoic acid (PHBA) plays a significant role in sustaining the oxidative stability of macadamia nut oil (MNO). However, PHBA undergoes thermal decarboxylation and loses its bioactive antioxidant properties. In this study, we determine PHBA degradation kinetics in oils at various heating temperatures, which provides fundamental understanding of PHBA thermal degradation in oils and oil quality changes during high-temperature processing. PHBA degradation kinetics in MNO, olive oil, and corn oil were evaluated at temperatures typical for cooking and frying. PBHA headspace concentration was measured using selected ion flow tube mass spectrometry. PHBA decarboxylation followed a zero-order reaction, where degradation could be affected by factors such as the type of oil matrix having different FA compositions, antioxidants, and component interactions. PHBA degradation activation energies ( E a ) showed that PHBA was more stable against thermal decarboxylation in MNO (85 kJ mol –1 ) than in olive oil (40 kJ mol −1 ) or corn oil (22 kJ mol −1 ). The higher enthalpy ( ) of decarboxylation in MNO (82 kJ mol −1 ) indicates that PHBA is more inhibited from decomposition than olive oil (37 kJ mol −1 ) or corn oil (19 kJ mol −1 ). Moreover, the negative entropy values ( ) of PHBA degradation from MNO (−192 J mol −1 K −1 ), olive oil (−277 J mol −1 K −1 ), and corn oil (−325 J mol −1 K −1 ) indicates that these oils impart some inhibitory properties against PHBA thermal decarboxylation.
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Small
·
2021
·Vol. 17
·期 37
·2102272
·
IF 13.281
Xi Guo,Biao Zhao,Kunxiang Xu,Shaomin Yang,Zhike Liu,Yu Han,Jie Xu,Dongfang Xu,Zhanao Tan,Shengzhong (Frank) Liu
Interface modification to minimize charge recombination and trapping for efficient charge transport is crucial for the performance of perovskite solar cells (PSCs). Herein, functionalized p-type blue carbon dots (B-CDs) are ventured as an interface passivation layer to enhance the efficiency and long-term stability of all-inorganic CsPbI 2 Br PSCs. It is found that first the blue carbon dots with abundant N H, C N, C O, and CO functional groups effectively passivate defects by reacting with I − and Pb 2+ ions in the perovskite through hydrogen and coordinative bonds. Second, the p-type B-CDs modifiers form a P–N junction with the n-type perovskite to provide efficient pathways for hole transfer and electron blocking. Third, the B-CDs increase the hydrophobicity of the perovskite film to improve the stability of CsPbI 2 Br PSCs. With the above advantages, the CsPbI 2 Br PSC with B-CDs modification shows an efficiency as high as 16.76%, one of the highest for its type. In addition, the modification renders significant improvement of air and light stability, with 95.33% of the initial PCE retained after storage in the ambient environment for 1000 h. This work demonstrates the great potential of B-CDs application in perovskite-based optoelectronic devices.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Hongxia Liu,Hui Mei,Shiping Li,Longkai Pan,Zhipeng Jin,Gangqiang Zhu,Laifei Cheng,Litong Zhang
Bismuth titanate (Bi 12 TiO 20 ) with unique sillenite structure has been shown to be an excellent photocatalyst for environmental remediation. However, the narrow light-responsive range and rapid recombination of photoinduced electrons-holes limit the photocatalytic performance of Bi 12 TiO 20 . To overcome the limitations, a practical and feasible way is to fabricate heterojunctions by combining Bi 12 TiO 20 with suitable photocatalysts. Here, using a facile chemical precipitation method, a novel and hierarchical core–shell structure of n-Bi 12 TiO 20 @p-BiOI (BTO@BiOI) heterojunction was rationally designed and synthesized by loading BiOI nanosheets on BTO nanofibers. The constructed BTO@BiOI composites exhibited significant charge transfer ability due to the synergistic effects of the built-in electric field between BTO and BiOI as well as close interfacial contacts. In addition, the narrow bandgap characteristics of the BiOI led to wide light absorption ranges. Therefore, the BTO@BiOI heterojunction exhibited an improved photocatalytic performance under visible light irradiation. The NO removal efficiency of optimal BTO@BiOI was 45.7%, which was significantly higher compared to that of pure BTO (3.6%) or BiOI (23.1%). Moreover, the cycling experiment revealed that BTO@BiOI composite has a good stability and reusability. The possible mechanism of photocatalytic NO oxidation over BTO@BiOI was investigated in detail.
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高影响因子
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