Nanomaterials
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2020
·Vol. 10
·期 4
·631
·
IF 4.324
Zhen Li,Libo Yu,Hao Wang,Huiwen Yang,Huan Ma
Light harvesting and electron recombination are essential factors that influence photovoltaic performance of quantum dots sensitized solar cells (QDSSCs). ZnO hollow microspheres (HMS) as architectures in QDSSCs are beneficial in improving light scattering, facilitating the enhancement of light harvesting efficiency. However, this advantage is greatly weakened by defects located at the surface of ZnO HMS. Therefore, we prepared a composite hollow microsphere structure consisting of ZnO HMS coated by TiO2layer that is obtained by immersing ZnO HMS architectures in TiCl4aqueous solution. This TiO2-passivated ZnO HMS architecture is designed to yield good light harvesting, reduced charge recombination, and longer electron lifetime. As a result, the power conversion efficiency (PCE) of QDSSC reaches to 3.16% with an optimal thickness of TiO2passivation layer, which is much higher when compared to 1.54% for QDSSC based on bare ZnO HMS.Keywords:TiO2passivation layer;ZnO hollow microspheres;quantum dots sensitized solar cells
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Journal of Materials Chemistry B
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2020
·Vol. 8
·期 32
·7160-7165
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IF 5.344
Tao Hu,Kangkai Xu,Shanhu Qiu,Yu Han,Juan Chen,Jian Xu,Ke Chen,Zilin Sun,Hong Yi,Zhonghua Ni
A sensitive fluorescent microfluidic sensor based on carbon quantum dots (CQDs), cadmium telluride quantum dots (CdTe QDs) aerogel and glucose oxidase (GOx) for urinal glucose detection was fabricated via a simple method. CQDs, emitting green fluorescence (emission peak at 520 nm) and the CdTe QDs, emitting red fluorescence (emission peak at 620 nm) under 365 nm ultraviolet irradiation, were synthesized. The as-prepared CQDs, CdTe QDs and GOx (C/CdTe QD-GOx) were mixed in a certain ratio and were then introduced into the microfluidic chip to construct a three-dimensional porous aerogel sensor after freeze-drying. A ratiometric fluorescence response was realized through the quenching of the red fluorescence by H2O2 produced from the glucose/GOx reaction, while the green fluorescence intensity stays constant. A small change in the ratio of the two fluorescence intensities led to a clear change in the fluorescent colour of the sensor, which can be easily observed under a UV lamp. The microsensor displayed a serial colour change from red to green with the changes in glucose concentration. The intensity ratio between the red fluorescence and green fluorescence (R/G value) indicates the glucose concentration. In our experiments, the optimal concentration ratio of CdTe QDs and CQDs was 0.5 : 1, and the optimal response time was 5 min. The detection range of glucose concentration was from 0 mM to 13 mM, and the detection limit was 0.223 mM. We also found that this glucose sensor has excellent selectivity, specificity and stability. The as-prepared microsensor can be stably stored for 30 days under −20 °C. Such a C/CdTe QD-GOx aerogel based microfluidic assay sensor provides a new approach towards the optical and quantitative detection of glucose, which enables daily urine glucose monitoring for the diabetic patients in a convenient way.
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ELECTROCHIMICA ACTA
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2020
·
IF 6.215
Tao Han,Xiaoping Yu,Yafei Guo,Mingli Li,Ji Duo,Tianlong Deng
As a unique and indispensable element in modern battery and energy industries, the recovery of lithium has attracted wide attention worldwide. In this work, the recovery of low concentration of Li + in geothermal water was carried out by a green and novel FePO 4 /K 2 NiFe(CN) 6 [FPO/KNiFC] electrochemical ion pump technique. Different K 2 MFe(CN) 6 (M = Cu, Co, or Ni) was synthesized and used to construct an electrochemical ion pump with FePO 4 . It was found that K 2 NiFe(CN) 6 has excellent electrochemical properties, and the recovery of Li + is mainly restricted by the insertion capacity and rate of the FePO 4 electrode. This problem was successfully solved by the modification of electrode using multiwalled carbon nanotube . Even though the optimized ion pump system has a low single insertion capacity for low concentrations of Li + , a cycle extraction method was developed and successfully realized high-effective recovery of Li + from geothermal water. Subsequently, a multi-stage extraction device was designed and proposed for the continuous recovery of low concentrations of Li + .
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LUMINESCENCE
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2020
·Vol. 35
·期 7
·1084-1091
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IF 1.855
Feifei Li,Yajie Yu,Fubing Xiao,Hao Liang,Can Liu,Pengfei Fan,Shengyuan Yang
A colorimetric assay for the determination and quantification of ascorbic acid (AA) is presented using silver nanoparticle (AgNP) single-walled carbon nanotube (AgNP/SWCNT) nanocomposites prepared using a microwave-assisted method. The AgNP/SWCNT nanocomposites possessed oxidase-like properties toward 3,3′,5,5′-tetramethylbenzidine (TMB) and could catalyze the oxidation of TMB to form a blue oxidation product (λ max = 652 nm) in the absence of H 2 O 2 . AA can specifically inhibit the oxidation of TMB, resulting in a decline of the absorbance value and blue colour fading. As such, amounts of AA can be assessed easily by the unaided eye and quantitatively using an ultraviolet–visible light spectrophotometer. Under the optimal reaction conditions, this strategy showed a good linearity ranging from 0.4 μM to 5.0 μM for AA detection, and the limit of detection was 130 nM. This assay was also applied for AA measurement in vitamin C tablets and juice samples that yielded satisfactory results.
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FOOD CHEMISTRY
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2020
·
IF 6.306
Li Wang,Shuang Shao,Million Paulos Madebo,Yuanyuan Hou,Yonghua Zheng,Peng Jin
Effect of nano-SiO 2 packing on postharvest quality and antioxidant capacity of two different loquat cultivars (white-flesh ‘Qingzhong’ and red-flesh ‘Dawuxing’) were determined. Results showed that nano-SiO 2 packing significantly inhibited internal browning, retarded the decline of total soluble solids, titratable acidity, ascorbic acid content and extractable juice in both cultivars. Decay index of nano-SiO 2 packing in ‘Dawuxing’ and ‘Qingzhong’ was 53.25% and 42.84% lower than control after the day 12, respectively. Meanwhile, nano-SiO 2 packing enhanced the contents of individual phenolic compounds and soluble sugar compounds, induced higher superoxide dismutase and catalase activities, which contributed to improving 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical scavenging capacity. Furthermore, the contents of total soluble solids, ascorbic acid and soluble sugar were higher in ‘Qingzhong’ than those in ‘Dawuxing’, which dedicated to better quality. These results indicated that nano-SiO 2 packing was a promising approach in inhibiting decay, maintaining quality and expanding shelf life of loquats.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2020
·
IF 7.1
Meiling Tian,Wenyue Xie,Ting Zhang,Yang Liu,Zhisong Lu,Chang Ming Li,Yingshuai Liu
This work reports a low-cost, fast and highly sensitive lateral flow immunoassay (LFIA) platform with Prussian blue nanoparticle (PBNP) as a new reporter, which efficiently mediates an on-demand cascade signal amplification by catalyzing oxidation of chromogenic reagent 3,3′,5,5′-tetramethylbenzidine (TMB). In this case, PBNPs are accumulated on the test line through the specific immune interaction, resulting in a blue-colored line. The colorimetric signal can be further amplified via the peroxidase mimic PBNP-catalyzed TMB oxidation to produce an insoluble blue-violet precipitate. Under an optimal condition, a limit of detection (LOD) at 10 pg mL −1 is achieved for rabbit IgG (RIgG) detection, which is 2–3 orders of magnitude better than the conventional LFIA strip using colloidal gold nanoparticle as a label. A macromolecular RIgG and a small molecular mycotoxin ochratoxin A (OTA) are also successfully analyzed in mimicking samples, demonstrating its good practicability of the proposed platform in a variety of fields.
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Nanoscale
·
2020
·Vol. 12
·期 7
·4562-4572
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IF 6.895
Jing Wang,Xinyue Liu,Liang Huang,Jiening Jin,Chenxing Jiang,Daquan Li,Huimin Wen,Jun Hu
The ratiometric fluorescence technique is of great interest due to its visualization characteristics. The construction of a reliable fluorescent ratiometric nanoprobe for high-sensitivity visual quantification is highly sought after but it is limited by poor stability and controllability. Herein, we report a robust dual-emissive quantum dot nanohybrid with precise color tunability and demonstrate its potential as a two-signal-change ratiometric probe for visual detection. A novel assembly strategy was developed for spatially implanting hydrophobic green and red quantum dots (QDs) into a silica scaffold to form a dual-emissive hierarchical fluorescent silica nanohybrid. The fluorescence intensity ratio and color of the nanohybrid were precisely tailored by altering the amounts of green and red QDs. Particularly, after the alkylsilane-mediated phase transfer and exterior silica shell growth, the nanohybrid exhibited the well-preserved fluorescence features of the original QDs and robust optical/colloid stability. An inner filter-based ratiometric nanoprobe for the visual determination of melamine was ultimately devised by combining the spectra-overlapped two-colored fluorescent nanohybrid with analyte-specific gold nanoparticles. Furthermore, based on the reversible fluorescence signal changes in two-colored QDs induced by melamine, a logic gate strategy for melamine monitoring was constructed. The newly developed fluorescent ratiometric nanoprobe shows great prospects for the visual and quantitative determination of analytes in a complex biological matrix.
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ANALYST
·
2020
·Vol. 145
·期 15
·5273-5279
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IF 3.978
Luping Feng,Jiani Yang,Sheng Zhang,Lixiang Zhang,Xi Chen,Pan Li,Yuan Gao,Shujing Xie,Yun Zhang,Hua Wang
A capillary-based fluorimetric analysis method was developed for probing glucose (Glu) in blood using Glu oxidase-anchored gold nanoclusters (GOD–AuNCs) and the ZIF-8 matrix. AuNCs were attached with GOD to be further encapsulated into the ZIF-8 matrix through the protein-mediated formation route. The resulting GOD–AuNCs@ZIF-8 nanocomposites could present the AuNC-improved catalysis of GOD and ZIF-8-improved environmental stability. The ZIF-8-enhanced fluorescence intensity of AuNCs could also be expected. Moreover, a capillary-based fluorometric platform was constructed for sensing Glu by coating the capillaries first with GOD–AuNCs and then the ZIF-8 matrix. Herein, Glu was introduced through the self-driven sampling to trigger the GOD-catalyzed production of hydrogen peroxide, which could induce the fluorescence quenching rationally depending on the Glu concentrations. The developed fluorimetric method could allow for the rapid and simple detection of Glu with the concentrations linearly ranging from 5.0 μM to 2.5 mM. Besides, the feasibility of practical applications was demonstrated by the evaluation of Glu in blood showing the recoveries of 96.2%–103.4%. Importantly, the proposed design of the capillary-based fluorimetric platform by the synergetic combination of catalysis-specific recognition and fluorescence signaling may open a new door toward extensive applications in the biological sensing, catalysis, and imaging fields.
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JOURNAL OF MEMBRANE SCIENCE
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2020
·
IF 7.183
Zhenhua Lü,Zhongwei Guo,Kaifei Zhang,Sanchuan Yu,Meihong Liu,Congjie Gao
This work focused on modification of polyamide based thin-film composite membrane via a novel strategy combining surface tertiary amination and zwitterionic functionalization for improved separation and anti-dye-deposition properties. Surface tertiary amination was conducted through grafting polyethyleneimine (PEI) onto the surface of base membrane at the sites of carboxylic groups activated by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide. Zwitterionic functionalization was implemented through in situ ring-open reaction between tertiary amine groups of grafted PEI molecules and 1, 4-butanesultone. It was found that grafting of PEI could enhance CaCl 2 /NaCl rejection ratio from 0.36 to 3.05 through reversal of surface charge at a sacrifice of pure water permeation coefficient from 9.7 to 8.6 l/m 2 h bar. The following incorporation of zwitterions under desired condition could resume pure water permeation coefficient to a higher value of 12.6 l/m 2 h bar and further enhance CaCl 2 /NaCl rejection ratio to 3.11. Furthermore, proper surface tertiary amination and zwitterionic functionalization could even significantly improve membrane resistance to deposition by both cationic and anionic dyes. Membrane's water permeation coefficients to aqueous Congo red, Victoria blue B and methylene blue solutions under steady state were enhanced by 72.5, 78.8 and 53.2%, respectively, and relative flux decline ratios were lowered by 80.5, 80.3 and 79.0%.
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CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
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2020
·
IF 0.936
Lan WU,Zhi-Wei LU,Ying MA,Jun-Jun ZHANG,Guang-Quan MO,Hai-Jun DU,Jian-Shan YE
A novel electrochemical non-enzymatic sensing system was fabricated based on carbon paste electrode (CPE) encapsulating copper metal-organic frameworks (Cu-MOF/CPE) for determination of glucose by chronoamperometry in alkaline media. The as-synthesized Cu-MOF exhibited high surface area and porous structures, and the presence of carbon pastes greatly improved the conductivity of the sensing electrode. This synergic effect led to the good catalytic activity of the resulting electrode toward glucose. Under the optimized experimental conditions, the oxidation peak currents were linearly dependent on glucose concentrations in a wide range of 5–3910 μmol/L and 3910–10950 μmol/L with a limit of detection (LOD) of 0.11 μmol/L and a short response time of 0.5 s. Moreover, the developed sensor showed long-time stability, excellent selectivity as well as high resistance towards interferences. This sensor was also applied to determination of glucose in serum samples with a satisfactory result, confirming its promising applications.
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FUEL
·
2020
·
IF 5.578
Guo Qiu,Biaohua Chen,Chongpin Huang,Ning Liu,Xiuliang Sun
Methods for the conversion of carbohydrates into 5-hydroxymethylfurfural (5-HMF), which is an important platform chemical, have been attracted extensive attention. In present study, Sn modified ionic liquid polymer (PIL-Sn) was prepared by one-pot polymerization of imidazole and epichlorohydrin, and utilized as a novel and efficient catalyst for 5-HMF production. The optimal 5-HMF yield of 51.1% with 99% conversion was obtained from glucose catalyzed by PIL-Sn in dimethyl sulfoxide at 130 °C with reaction time of 1 h. This catalytic system can also be applied for the transformation of other carbohydrates with satisfactory yields. The mechanism of PIL-Sn-catalyzed conversion of glucose to 5-HMF has been studied using density functional theory (DFT) calculations. The DFT results showed that the five-coordinated SnCl 5 - as a preferred species played an important role in the isomerization of glucose to fructose. This research provides a new strategy to design efficient catalysts for 5-HMF synthesis.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 7
·1-8
·
IF 6.232
Li Shuhuai,Pang Chaohai,Ma Xionghui,Zhao Min,Li Haibo,Wang Mingyue,Li Jianping,Luo Jinhui
A luminescent double recognition nanoprobe is described as a new strategy for the selective determination of chiral molecules. C-dots/Ir/Au fluorescent nanoparticles, synthesised under hydrothermal conditions, are used as a high-performance probe in combination with a molecularly imprinted polymer (MIP) and calix[6]arene as a double recognition element. Thiolated calix[6]arene is grafted on C-dots/Ir/Au as the first recognition element, which then forms a host–guest complex with the target molecule levodopa (L-DOPA). Subsequently, an MIP is prepared on the C-dots/Ir/Au (MIP/C-dots/Ir/Au) by chemical polymerisation. After the removal of L-DOPA, double recognition imprinting cavities are formed. The fluorescence intensity at 478 nm of the nanoprobe is effectively quenched by adsorption of L-DOPA on MIP/C-dots/Ir/Au, which provides a method for L-DOPA determination. Owing to the double recognition strategy, this method has excellent selectivity which can effectively avoid interference from enantiomer D-DOPA, and a imprinting factor of 7.1 is obtained for L-DOPA. This accurate and reliable method, with a wide linear range (5 × 10 −10 to 1.2 × 10 −7 mol L −1 ) and a low limit of detection (1.45 × 10 −10 mol L −1 ), was successfully applied to the determination of L-DOPA in real samples, giving standard recoveries of 89.7–110.0%. Thus, the proposed sensing method provides a viable approach for the determination of a single enantiomer.
Schematic presentation of the MIP/C-dots/Ir/Au for L-DOPA detection. A fluorescence double chiral recognition nanoprobe is prepared of C-dots/Ir/Au nanoparticles as signal probe, and a molecularly imprinted polymer (MIP) and calix[6]arene as a double recognition element. Owing to the double recognition strategy, this method has strong specificity and can effectively avoid interference from enantiomers and racemates.
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