CHEMICAL PAPERS
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2019
·Vol. 74
·期 2
·485-497
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IF 1.246
Quan Cong,Liu Jiayu,Sun Wei,Cheng Xinjian
It is extremely necessary to detect heavy metals sensitively and selectively, especially the ions that will cause great harm to humans and the environment. This work deals with two fluorescent chemosensors and their outstanding role when detecting Zn 2+ and Cd 2+ ions. First, a small molecular chemosensor (TPB) has been designed and synthesized via Suzuki reaction using one part of benzene-1,3,5-triyltriboronic acid and three parts of 2-bromo-1, 10-phenanthroline as starting materials. And then, its corresponding macromolecular fluorescent chemosensor (PTPB) was synthesized. The infrared spectra, mass spectrometry (MS), and 1 H-NMR were used to study the structures of TPB and PTPB. From what has been studied, the TPB and PTPB were stable in a relative wide pH range. As soon as the Cd 2+ and Zn 2+ ions added, fluorescence of the two sensors TPB and PTPB was changed obviously. In addition, PTPB was found have better performance to both Cd 2+ and Zn 2+ than TPB through the ‘‘molecular wire’’ mechanism. Job’s plots were also be tested, showing that the combination ratio of TPB and PTPB to Cd 2+ and Zn 2+ were both 3:1 (ion/sensor). In addition, the minimum detection limits of the macromolecular chemosensor PTPB for Cd 2+ and Zn 2+ reached 0.424 μM and 1.27 μM, respectively.
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STARCH-STARKE
·
2019
·
IF 1.795
Jia Shao,Zheng Zhang,Shixing Zhao,Sui Wang,Zhiyong Guo,Hongzhen Xie,Yufang Hu
As promising soft materials, various excellent properties of hydrogels have received widespread attention during recent years. Mechanical properties and self-healing performance are required characteristics for hydrogels in practical applications. An important challenge is to develop hydrogels exhibiting mechanical performance and self-recoverability through physical cross-linking. In this work, the authors report a hydrogel consisting of a fully physically linked poly (vinyl alcohol)/agarose (PVA/AG) dual-network, which is of high toughness and self-healing properties. The synthesis process of the PVA/AG hydrogel is convenient, with AG as the first network, and hydrogen bonding and crystal-associated PVA as the second network to form a dual physical crosslink. Due to this physical cross-linking, the PVA/AG hydrogel has good mechanical properties (tensile strength of 6.5 MPa to 14.6 MPa, ductility of 168% to 214%). The highest compressive strength of hydrogel is up to 3.66 MPa, which is almost 8 times that of pure PVA hydrogel. In addition, it has excellent self-healing properties without stimulation or healing agents. Compared to pure PVA hydrogel, PVA/AG hydrogels have higher thermal stability due to higher decomposition temperatures and lower degradation rates. In this study, the authors also initially explore the potential application of obtained hydrogel.
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JOURNAL OF CATALYSIS
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2019
·
IF 7.723
Haiqiang Lin,Hongyan Qu,Weikun Chen,Kang Xu,Jianwei Zheng,Xinping Duan,Hesheng Zhai,Youzhu Yuan
In gas-phase chemoselective hydrogenation of crotonaldehyde on Ag-based catalysts, zirconia doping on silica supports was found to improve catalytic performance in terms of unsaturated alcohol selectivity, hydrogenation activity, and stability. The surface modification of silica by zirconia doping favors the fine dispersion of Ag species due to the enhanced quantity and strength of surface acid sites, which enable construction of abundant catalytic sites effective for C O bond hydrogenation. High crotyl alcohol selectivity, exceeding 80%, and significant inhibition of monohydrogenation on the C C bond were observed on the optimal Ag/Zr–SiO 2 catalyst. Dynamic O 2 chemisorption measurement revealed that the pure Ag powders did not chemisorb O 2 irreversibly under 323 K, but SiO 2 or Zr–SiO 2 supported Ag catalysts did. The amounts of Ag active for O 2 chemisorption, which are at least one order of magnitude lower than that of surface Ag derived from TEM and XRD characterizations, match well with the perimeter interface Ag of hemispherical particles. A strong correlation between hydrogenation activity and O 2 uptake on those Ag/SiO 2 and Ag/Zr–SiO 2 catalysts with different Ag dispersions and deactivation degrees was observed, implying that the effective catalytic sites for crotonaldehyde chemoselective hydrogenation may originate from accessible interface sites with unique redox properties. Catalyst induction and deactivation were observed on both Ag/SiO 2 and Ag/Zr–SiO 2 catalysts in real catalytic operation. Changes in metal stable interface structure, rather than metal aggregation and coagulation, are assumed to be the main cause of irreversible catalyst deactivation, because the apparent Ag particle sizes changed slightly, but the oxygen chemisorption ability deteriorated considerably. Electropositive Ag sites interacting with neighboring oxygen from oxide supports at the ternary Ag–ZrO 2 –SiO 2 interface are proposed to account for highly selective C O bond hydrogenation to produce the desired unsaturated alcohol.
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Journal of Materials Chemistry A
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2018
·Vol. 6
·期 10
·4365-4373
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IF 9.931
Liguo Gao,Likun Wang,Xiaogang Ding,Erling Zhao,Shuzhang Yang,Yingyuan Zhao,Yanqiang Li,Shufeng Wang,Tingli Ma
The power conversion efficiency (PCE) of perovskite solar cells (PSCs) can be improved by introducing appropriate additives into perovskite precursor solutions. However, the exact role and mechanism of additives are still unclear. In this study, self-designed cognition experiments were conducted to improve the hole extraction efficiency, as well as to deeply understand the working principle of additives. A common hole transport material, 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl) amino]-9,9′-spirobifluorene (spiro-OMeTAD), was used as an additive for bulk heterojunction PSCs (BHJ-PSCs). The results showed that the PCE of mesoporous BHJ-PSCs (M-BHJ-PSCs) was enhanced by more than 15% when an extremely low concentration of spiro-OMeTAD additive was added. However, the crystallization of the perovskite was hampered and the recombination risk increased when grain boundaries increased in the perovskite layer. Planar BHJ-PSCs were fabricated to further investigate the role of additives. In comparison with those in planar BHJ-PSCs, the hole extraction efficiency and diffusion length significantly improved in M-BHJ-PSCs due to the transport paths and relay effects caused by the spiro-OMeTAD additive. Subsequently, exact functions and a new working principle of additives in BHJ-PSCs were proposed. This study may extend the possibilities of designing highly efficient PSCs through the promotion of additive research and application.
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ANALYTICA CHIMICA ACTA
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2018
·
IF 5.123
Yang Li,Qingfen Niu,Tao Wei,Tianduo Li
A novel bifunctional thiophene-based Schiff base TS as a colorimetric and fluorescent turn-on sensor for rapid and simultaneous detection of Al 3+ and Zn 2+ ions with high selectivity and sensitivity has been developed. The sensor shows remarkable fluorescence enhancement response for Al 3+ and Zn 2+ over a broad pH range with good anti-interference capability, which accompanied with an obvious color change easily detected by naked eyes. Sensor TS can detect as low as 3.7 × 10 −9 M for Al 3+ and 3.0 × 10 −8 M for Zn 2+ , whereas respective association constants are 1.16 × 10 4 M −1 and 2.08 × 10 4 M −1 . With the help of fluorescence titration and Job's plot, the stoichiometric ratio of TS with Al 3+ /Zn 2+ was determined to be 1:1. The sensing mechanism of sensor TS with Al 3+ /Zn 2+ based on the chelation-enhanced fluorescence (CHEF) was analyzed in detail through 1 H NMR titration, FTIR, HRMS and DFT studies . Moreover, sensor TS has been applied to the detection of Al 3+ and Zn 2+ in real environmental water and food samples as well as the filter paper-based test strips. Furthermore, sensor TS has good cell-permeability and can be used to selectively sense intracellular Al 3+ and Zn 2+ by bioimaging.
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PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Ying Xu,Shengnan Wang,Xiaoyan Hou,Zhe Sun,Yong Jiang,Zhongbing Dong,Quanbao Tao,Jun Man,Yan Cao
N, P, S co-doped graphene quantum dots (NPS-GQDs) were prepared via a one-step wet chemical plus dialysis method directly using anthracite coal as raw material. This facile oxidation process simultaneously synthesized graphene quantum dots (GQDs) and doped N, P and S atoms on edges or forming functional groups of GQDS. X-ray photoelectron spectroscopy (XPS) proved that the involved heteroatoms were successfully doped on GQDs. The local doping of N, P and S on GQDs can reach high levels as 5.6%, 3.7% and 3.7% (by atomic) during XPS detection, respectively. Raman spectra showed that the amount of defects or disorders of prepared GQDs increased during the transition of the coal hunk toward the nano-GQDs. The effect of graphitizing degree of applied coals (varied coal ranks) on the formation of GQDs implied that raw coals with too high or too low graphitizing degree were not optimizing for the formation of high-quality GQDs. The prepared NPS-GQDs showed excellent properties on the excitation-dependent fluorescence and the quench by some trace metals. Thus, the NPS-GQDs were applied to detect of Pb 2+ in both a DI water and a multi-elements analysis matrix, exhibited wide linear detection range (1–20 μM) and a detection limit of 0.75 μM.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2018
·
IF 5.091
Tianxiang Lan,Rui An,Zheng Liu,Kaijun Li,Jun Xiang,Gongyan Liu
The stable and efficient immobilization of silver nanoparticles (AgNPs) on/into processable biomass-based macro-support with porous networks is a promising and sustainable strategy to achieve both high catalytic activity and excellent reusability for heterogeneous catalysis . In this work, a collagenic composite film was facilely fabricated at room temperature , via the self-assembly of natural collagen fibers (CFs) and gallic acid modified silver nanoparticles (GA@AgNPs) induced by chromium (III) cross-linking in water. The morphology and microstructure of such GA@AgNPs-Cr-CFs composite film was investigated by Scanning Electron Microscope (SEM) and X-ray Photoelectron Spectroscopy (XPS), respectively. The results revealed that the cross-linking based on the coordinated complexation between chromium ions (Cr 3+ ) and carboxyl groups on CFs and GA@AgNPs played the critical role in the interwoven of collagen fibers, leading to a three dimensional (3D) interconnected porous network of the composite film with simultaneously incorporation and high payload of silver nanoparticles. Furthermore, this GA@AgNPs-Cr-CFs composite film exhibited excellent catalytic activity toward the reduction of 4-nitrophenol (4-NP), taking the advantage of its high specific surface area given by the interwoven fibrous network structure. More than that, such sustainable composite catalyst could be easily recovered and reused for ten cycles because of its high stability based on cross-linking. This catalytic platform constructed by natural fibers , noble metal nanoparticles and trivalent metal ions showed a sustainable avenue for heterogeneous catalytic system.
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PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Yang-Yi Liu,Han-Ping Zhang,Bin Zhu,Han-Wen Zhang,Liang-Dong Fan,Xiao-Yan Chai,Qian-Ling Zhang,Jian-Hong Liu,Chuan-Xin He
In the past few decades, much attention has been paid to developing electrocatalysts with low cost and high efficiency for the hydrogen evolution reaction (HER) because of its potential impact on the energy fields. Besides, recent research demonstrates that interfaces play an important role in the electrocatalytic process. Herein, C/N-co-doped Pd coated Ag (Ag@Pd) nanowires (NWs) were prepared through a calcination process. In this process, the C/N–Ag@Pd interfaces consisted by the Pd-N bonds and the core/shell structure of Ag@Pd were formed. The effect of the calcination temperature on the formation of the C/N–Ag@Pd interfaces were investigated in detail. Moreover, C/N-co-doped Ag@Pd NWs exhibited excellent catalytic activity for HER with a small overpotential of 111 mV to afford a current density of 10 mA cm −2 , a low Tafel slope of 64 mV Dec −1 and good stability. The relationship between the HER activity and the C/N–Ag@Pd interfaces were built. Furthermore, such design principle for constructing interfaces between noble metal alloys and C/N by direct sintering can offer a new strategy for the developing more efficient electrocatalysts.
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POLYMER COMPOSITES
·
2018
·
IF 1.943
Jingjing Zhang,Hairong Li,Die Hu,Dong Fang,Zhiping Luo,Junyang Tu,Jing Huang,Ming Jiang,Chuanxi Xiong
Dielectric materials with low dielectric loss are highly desirable for future energy storage and management. Relatively high dielectric loss and complex fabrication process with high cost are current major factors limiting percolative dielectric composites for applications. In this study, low dielectric loss has been obtained using multi-interface silver/epoxy/poly(vinylidene fluoride) (Ag/epoxy/PVDF) percolative composites by simple thermal curing and mechanical crushing, coupled with melt mixing and hot pressing. Isolated Ag/epoxy islands were formed in the PVDF matrix. The dielectric permittivity of the composite near the percolation threshold reached 132 whereas the loss tangent was around 0.1 at 100 Hz. This multi-interface structure played an important role in suppressing the dielectric loss and achieving the relatively high dielectric permittivity in these composites. Our results suggest that the simple and low-cost fabrication of the Ag/epoxy/PVDF is a promising approach for the development of low-loss percolative dielectric composites. POLYM. COMPOS., 39:E2606–E2610, 2018. © 2018 Society of Plastics Engineers
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Energy & Environmental Science
·
2018
·Vol. 12
·期 1
·194-205
·
IF 30.067
Jin-Qi Xie,Ya-Qiang Ji,Jia-Hui Kang,Jia-Li Sheng,Da-Sha Mao,Xian-Zhu Fu,Rong Sun,Ching-Ping Wong
Although integrated energy storage devices, such as in-plane micro-supercapacitors (MSCs), are attractive for powering portable microelectronic devices, it is still challenging to develop patterning techniques with high practicability and to rationally design and fabricate electrochemically active materials using feasible procedures. Here, we propose a facile solution-immersion method of fabricating interdigitated copper electrodes with an in situ converted array of Cu(OH)2@FeOOH nanotubes (NTs). A copper current collector can be patterned together with widely employed copper circuits by a facile copper-patterning approach based on cost-effective electroless catalytic deposition of copper with patterned Ag catalysts, which is greatly conducive to the integration of in-plane energy storage devices into microelectronic systems. Furthermore, the rationally designed array of Cu(OH)2@FeOOH NTs, which was converted in situ from the patterned copper electrodes, was demonstrated to be an excellent electrochemically active material with advantages that included a porous structure with a large specific surface area, excellent wettability by the electrolyte, short ion diffusion lengths and one-dimensional electron transport pathway. The resulting MSC devices that were fabricated with the interdigitated Cu(OH)2@FeOOH/Cu electrodes exhibited a high specific capacitance (58.0 mF cm−2 at 0.1 mA cm−2), a high energy density (18.07 μW h cm−2), excellent cycling stability and desirable flexibility.
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Analytical Methods
·
2019
·Vol. 11
·期 34
·4382-4389
·
IF 2.378
Fanglin Ming,Jingzhou Hou,Danqun Huo,Jun Zhou,Mei Yang,Caihong Shen,Suyi Zhang,Changjun Hou
A luminescent amino-functionalized metal–organic framework (Cu–MOFs) was synthesized from 2-aminoterephthalic acid and Cu(II) ions by a solvothermal method. Cu–MOFs displayed blue fluorescence with a peak at 430 nm under 330 nm excitation. Its structure was characterized by FTIR, TEM, XRD, and XPS. The fluorescence of the Cu–MOFs was quenched by Fe3+ in aqueous solutions. The limit of detection was 0.5 μM, and the linear working range extended from 2 μM to 35 μM. Additionally, a good logarithmic relationship between relative fluorescence intensity (F/F0) and Fe3+ concentrations ranging from 2 to 180 μM was obtained with a detection limit of 1.56 μM (R2 = 0.9975). No clear interference was observed when challenged with a wide variety of cations and anions. The recoveries from spiked real water samples were in the range of 91.7–107.7%, and the detection results were consistent with inductively coupled plasma mass spectrometry (ICP-MS) results. Therefore, the fluorescent sensor has great potential in environmental monitoring.
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FOOD AND AGRICULTURAL IMMUNOLOGY
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2018
·
IF 2.568
Zhi-Li Xiao,Wei Tian,Zhen-Lin Xu,Yuan-Ming Sun
In this study, we develop a sensitive indirect competitive chemiluminescent enzyme immunoassay (ic-CLEIA) to detect cadmium (Cd) in cereals. A luminol-hydrogen peroxide chemiluminescence system catalysed by horseradish peroxidase (HRP) was used as the signal detecting system. The method showed a half-maximal inhibition concentration (IC50) of 0.5 ng/mL and a limit of determination (LOD) of 0.06 ng/mL. The assay indicated an effective linear range from 0.16 to 1.56 ng/mL. There were no obvious cross-reactivities with other metal ions, including Hg2+, Pb2+, As2+, Ag+, Fe3+, Cu2+, Cr2+, Au3+, Ca2+, Mg2+, Mn2+ and Zn2+. Recovery rates ranged from 79.2% to 120.0% for rice, maize, wheat, brown rice and glutinous rice samples. Twenty-five practical cereal samples were analysed, and the comparative analysis of the results showed a strong correlation (r = 0.984) between the CLEIA and the GFAAS methods. The results indicated that the ic-CLEIA developed was acceptable to screen for cadmium in cereal samples.
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