COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
·
IF 3.131
Boqiong Jiang,Beilong Lin,Zhiguo Li,Shuang Zhao,Ziying Chen
A series of Mn/TiO 2 catalysts were prepared by ultrasonic spray pyrolysis (USP) method for selective catalytic reduction (SCR) of NOx from flue gas at low temperatures. The highest activity of Mn/TiO 2 was obtained with a Mn/Ti ratio of 0.5. When Fe was doped into Mn(0.5)/TiO 2 , the NOx conversion rate on Fe(0.05)-Mn(0.5)/TiO 2 was increased by approximately 10 % at 120–180 °C. The samples were characterized by XRD , SEM , H 2 -TPR, and N 2 adsorption analyses. Results revealed that Mn(0.5)/TiO 2 with Mn/Ti ratio of 0.5 presented the lowest crystallinity , the highest surface area, and the highest redox ability. Although the surface area was significantly decreased by Fe doping, it also reduced the crystallinity and crystal size of the catalysts, thereby increasing the O concentration on the surface of catalyst. Moreover, Fe(0.05)-Mn(0.5)/TiO 2 displayed a higher redox ability than the other catalysts. At 120–240 °C, the activation energy decreased from 27.65 kJ/mol on Mn(0.5)/TiO 2 to 14.46 kJ/mol on Fe(0.05)-Mn(0.5)/TiO 2 , thereby facilitating the activation of the reaction on Fe(0.05)-Mn(0.5)/TiO 2 . Despite that the NO and NH 3 adsorptions were lower on Fe(0.05)-Mn(0.5)/TiO 2 than on Mn(0.5)/TiO 2 , the intermediates on Fe(0.05)-Mn(0.5)/TiO 2 , particularly nitrates, were easily activated to participate in the reaction, leading to increasing catalytic activity.
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ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Daming Chen,Song Yan,Haijun Chen,Lu Yao,Wei Wei,Hualin Lin,Sheng Han
Hierarchical Ni–Mn Layered Double Hydroxide (Ni–Mn LDH) nanosheets grow on a nitrogen-doped carbon foam skeleton through a one-step hydrothermal reaction . LNCF-2 exhibits high specific capacitance (2128.3 F g −1 at 0.5 A g −1 ) and good cyclic stability (94.3% retention after 5000 cycles at 2 A g −1 ) as an electrode material for supercapacitors . Furthermore, as a positive electrode material for an asymmetric supercapacitors (ASCs), it also has a high specific capacitance (125.1 F g −1 at 0.5 A g −1 ) and an excellent cyclic stability (80.1% retention after 10000 cycles at 5 A g −1 ). The increase in electrochemical performance is attributed to the high Faradaic pseudocapacitance of Ni-Mn LDH and the introduction of three-dimensional carbon foam. Because the introduction of three-dimensional carbon foam can provide an interconnection network for electron and ion transfer, allowing efficient charge exchange.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Hui Zhang,Xue-Tao Tian,Yue Shang,Yu-Hao Li,Xue-Bo Yin
Chemotherapy remains restricted by its toxic adverse effects and resistance to drugs. The treatment of nitric oxide (NO) combined with imaging-guided physical therapy is a promising alternative for clinical applications. Herein, we report nanoscale metal–organic framework (NMOF) systems to integrate magnetic resonance (MR) imaging, spatiotemporally controllable NO delivery, and photothermal therapy (PTT) as a new means of cancer theranostics. As a proof of concept, the NMOFs are prepared with biocompatible Zr4+ ions and Mn-porphyrin as a bridging ligand. By inserting paramagnetic Mn ions into porphyrin rings, Mn-porphyrin renders the NMOFs strong T1-weighted MR contrast capacity and high photothermal conversion for efficient PTT. S-Nitrosothiol (SNO) is conjugated to the surfaces of the NMOFs for heat-sensitive NO generation. Moreover, single near-infrared (NIR) light triggers the controllable NO release and PTT simultaneously for their efficient synergistic therapy with one-step operation. Upon intravenous injection, NMOF–SNO shows effective tumor accumulation as exposed by the MR images of the tumor-bearing mice. When exposed to the NIR laser, the tumors of mice injected with NMOF–SNO are completely inhibited, verifying the efficiency of NMOF–SNO. For the first time, Mn-porphyrin NMOFs are developed to be an effective theranostic system for MR imaging-guided controllable NO release and photothermal synergetic therapy under single NIR irradiation.
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Journal of Materials Chemistry B
·
2018
·Vol. 6
·期 21
·3586-3599
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IF 4.776
Xiaoqin Chen,Jing Sun,Huan Zhao,Ke Yang,Yuda Zhu,Hongrong Luo,Kui Yu,Hongsong Fan,Xingdong Zhang
For synchronous theranostic systems, there are two areas of focus. These are: excellent in vivo imaging and a multi-drug resistance (MDR) reversing ability for chemotherapy. Upconversion nanoparticles (UCNPs) exhibiting bright red emission in the “optical window in biological tissue (600–1100 nm)” could be a very useful candidate, although there have only been a few reports on UCNP-based conjugates with a MDR reversal ability explored for chemotherapy. Herein, we report an innovative theranostic system (D-UNT) via binding of an antitumor drug (DOX) and a MDR reversal agent (TPGS) to NaY(Mn)F4:Yb/Er UCNPs (UN) with synthetic optimized red emission and properties. The in vitro study demonstrated that the D-UNT was uptaken into drug-resistant MCF-7/ADR cells via caveolin dependent endocytosis and overcame P-gp mediated efflux. The cytotoxicity was significantly promoted to be much higher than that of free DOX. Accordingly, our D-UNT illustrates an enhanced reversal ability for chemotherapy. Our in vivo study further indicated that the D-UNT had excellent therapeutic efficacy against MDR tumors with minimal organ toxicity detected. In vivo deep-tissue imaging showed that the D-UNT accurately diagnosed MDR tumors at a 1.5 cm depth with high-contrast luminescent signals. Thus, the D-UNT is an effective theranostic system for the diagnosis and therapeutic treatment of MDR tumors. The present work opens new pathways to engineering powerful theranostic agents to simultaneously target, image and kill deep-tissue MDR tumor cells.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
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IF 11.698
Hua Zhou,Huanghui Xu,Yun Liu
Deriving more valuable products from renewable lignocellulosic biomass is attractive but still remains major challenges, the insufficient lignin valorization is considered as one of the main obstacles. Here, we report a novel catalyst comprised of cobalt nanoparticles (NPs) encapsulated in graphitic carbon tailored with manganese and nitrogen heteroatoms (Co-Mn/N@C), fabricated by pyrolyzing a mixture of Co/Mn-lignin complex and dicyandiamide. The as-synthesized Co-Mn/N@C catalyst exhibits excellent activity and recyclability for oxidizing biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) in aqueous system using O 2 as oxidant. The structure-performance relations of the catalyst are investigated, suggesting that Mn/N-doped carbon can activate the reactivity of Co NPs for HMF oxidation by tuning the electronic structure of embedded metal NPs. Additionally, isotopic labelling experiments reveal the role of water and O 2 for FDCA production using Co-Mn/N@C as catalyst. This work not only demonstrates the integrated biorefinery strategy, but also provides a new approach for sustainable, low-cost heterogenous catalysts preparation.
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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
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2018
·Vol. 18
·期 4
·2993-2999
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IF 1.354
Liu Chun-Ling,Hou Chang-Jun,Huo Dan-Qun
In this work, a simple room-temperature phosphorescence (RTP) method was first proposed to detect adriamycin, by using a functional material of Mn doped ZnS quantum dots (Mn–ZnS QDs) composited with poly(diallyldimethylammonium chloride) (PDDA). After PDDA was associated to the
Mn–ZnS QDs, the RTP intensity was significantly enhanced. As a result, Mn–ZnS QDs/PDDA nanoassemblies greatly improve the adriamycin detection ability of QDs and provide an important method for developing more effective and sensitive adriamycin detection sensor. The method based
upon RTP has a linear range from 0.5 to 64.0 μM with a detection limit (3σ/s) for adriamycin of 0.45 μM. The developed method was further successfully applied to detect adriamycin in human serum samples (diluted 50 times) with satisfactory results, and
the recovery ranged from 98.3 to 101.3.
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SENSORS AND ACTUATORS B-CHEMICAL
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2014
·
IF 3.84
Yang Zhang,Jinchao Shen,Hong Yang,Yan Yang,Zhiguo Zhou,Shiping Yang
A magnetic sensor for Cd 2+ has been developed based on (Zn, Mn)-doped iron oxide nanoparticles [(Zn, Mn)Fe 3 O 4 NPs], which was modified by ethyl 1-(2-(3′,4′-dihydroxyphenyl)-2-oxoethyl)-1H-1,2,3-triazole-4-carboxylate (ETC). ETC provided the binding sites to Cd 2+ to induce the transformation of (Zn, Mn)Fe 3 O 4 NPs from a dispersed to an aggregated state with a corresponding increase in the transverse relaxation time ( T 2 ) of surrounding water protons. Owing to the special strong interaction between ETC and Cd 2+ , ETC coordinated (Zn, Mn)Fe 3 O 4 [(ETC-(Zn, Mn)Fe 3 O 4 )] NPs exhibited a low limit of detection of Cd 2+ of 3.5 nM and a high selectivity over other metal ions . Furthermore, ETC-(Zn, Mn)Fe 3 O 4 NPs can be used to detect Cd 2+ in living cells by magnetic resonance (MR) imaging.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2015
·
IF 5.33
Bo Sun,Xiaohong Guan,Jingyun Fang,Paul G. Tratnyek
MnO4– was activated by HSO3–, resulting in a process that oxidizes organic contaminants at extraordinarily high rates. The permanganate/bisulfite (PM/BS) process oxidized phenol, ciprofloxacin, and methyl blue at pHini 5.0 with rates (kobs ≈ 60–150 s–1) that were 5–6 orders of magnitude faster than those measured for permanganate alone, and ∼5 to 7 orders of magnitude faster than conventional advanced oxidation processes for water treatment. Oxidation of phenol was fastest at pH 4.0, but still effective at pH 7.0, and only slightly slower when performed in tap water. A smaller, but still considerable (∼3 orders of magnitude) increase in oxidation rates of methyl blue was observed with MnO2 activated by HSO3– (MO/BS). The above results, time-resolved spectroscopy of manganese species under various conditions, stoichiometric analysis of pH changes, and the effect of pyrophosphate on UV absorbance spectra suggest that the reactive intermediate(s) responsible for the extremely rapid oxidation of organic contaminants in the PM/BS process involve manganese(III) species with minimal stabilization by complexation. The PM/BS process may lead to a new category of advanced oxidation technologies based on contaminant oxidation by reactive manganese(III) species, rather than hydroxyl and sulfate radicals.
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CHEMISTRY OF MATERIALS
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2013
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IF 8.238
Jun Xie,Changzhi Yan,Yu Zhang,Ning Gu
Monodisperse magnetic Mn–Zn ferrite nanostructures with various morphologies have been successfully synthesized via high-temperature decomposition of metal acetylacetonate (acac) in the presence of oleic acid (OA) and oleyamine (OAm). In a classical crystal nucleation/growth process, differential stabilization of OA on specific crystal facets may alter relative crystal growth rates, resulting in the formation of zero-dimensional (0-D) spherical, cubical, and starlike nanocrystals (ca. 9, 11, 16 nm), respectively. Furthermore, shortening nucleation duration might bring a deficient nucleation and a rapid increase in monomer concentration, which accelerates the subsequent growth process of nanocrystals, leading to the formation of the starlike nanocrystals with larger size (ca. 19–23 nm). They are further oriented to assemble reciprocally, gradually forming initial three-dimensional (3-D) “branched” nanoclusters (ca. 30–40 nm) to minimize the magnetostatic energy, owing to their size-dependent magnetic dipolar interaction. In addition, the surface-defect-induced secondary growth of the “branched” nanoclusters may considerably improve their uniformity, accompanied by the size increase in the presence of the monomers, resulting in the final “multibranched” nanoclusters with formation of sharp or obtuse edges (ca. 45–50 nm). Our study reveals the transformation of 0-D nanocrystals to 3-D nanoclusters as well as the shape evolution mechanism, which provide a versatile synthetic strategy for shape-controlled nanostructure. The multibranched nanoclusters have the higher magnetization and magnetically induced heating efficiency in an alternating current magnetic field, which can be used as promising heating agents for biomedical application.
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MICROCHIMICA ACTA
·
2014
·Vol. 182
·期 1
·193-200
·
IF 3.719
Ren Xiaohui,Liu Haochi,Chen Ligang
We show that Mn(II)-doped ZnS quantum dots coated with an acrylamide-based molecularly imprinted polymer (MIP-coated QDs) can act as a fluorescent probe for the selective and sensitive detection of the insecticide chlorpyrifos (CPF). The fluorescence of the coated QDs is quenched on loading the MIP with CPF, and the effect is much stronger for the MIP than for the non-imprinted polymer. The MIP-coated QDs were characterized by fluorescence spectrophotometry, X-ray powder diffraction, and scanning electron microscopy. Under optimal conditions, the relative fluorescence intensity of the MIP-coated QDs decreases linearly with the increasing concentration of CPF in the 0.3–60 μmol L −1 concentration range, and the detection limit is 17 nmol L −1 . The method has been used for the determination of CPF in spiked water samples and gave recoveries in the range from 87.1 to 94.5 % with relative standard deviations in the 2.9 to 6.5 % range. The method is simple, safe and inexpensive.
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ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Hongyan Chen,Yani Ai,Fan Liu,Xing Chang,Yuan Xue,Qi Huang,Chi Wang,Hualin Lin,Sheng Han
Hierarchical nanoarchitecture and composition can offer preponderances for enhancing pseudocapacitor performances. This paper reports on the three-dimensional hierarchical carbon-coated Ni–Mn layered double hydroxide on nickel foam (LNC) electrode material prepared via a facile two-step hydrothermal reaction. The resulting performance of the LNC composite material has high specific capacitance (1916 F g −1 ) and good cycling stability (91% retention after 5000 charge–discharge cycles). Moreover, the material can be directly used as an integrated flexible electrode with excellent rate capability (79.5% retention at 10 A g −1 ), which is significant in practical applications and large-scale syntheses. Furthermore, the LNC materials acting as a positive electrode for the asymmetric supercapacitor also exhibit high specific capacitance of 120.67 F g −1 at 0.5 A g −1 and excellent cycling stability with 84.2% capacitance retention after 5000 cycles at a current density of 5 A g −1 .
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FUEL PROCESSING TECHNOLOGY
·
2016
·
IF 3.847
Wei Li,Rui-tang Guo,Shu-xian Wang,Wei-guo Pan,Qi-lin Chen,Ming-yuan Li,Peng Sun,Shu-ming Liu
Heavy metals (such as Zn and Pb) have a deactivation effect on the catalyst for selective catalytic reduction of NO with NH 3 . In this study, it was found that the modification of Mn/TiO 2 catalyst by Nb could greatly enhance its Zn resistance. From the characterization results of BET, XRD, H 2 -TPR, NH 3 -TPD, it may be concluded that the introduction of Nb into Mn/TiO 2 catalyst would lead to its lower crystallinity , more acid sites and higher concentrations of Mn 4 + and surface chemisorbed oxygen. The results of in situ DRIFT study reveal that the NH 3 -SCR reactions over Mn/TiO 2 and Mn-Nb/TiO 2 all obey both the Langmuir-Hinshelwood mechanism and the Eley–Rideal mechanism, and the doping of Nb on Mn/TiO 2 catalyst could promote the adsorption of NH 3 and NOx species on it. All these features make a contribution to the high SCR activity and good Zn resistance of Mn-Nb/TiO 2 catalyst.
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