MICROCHIMICA ACTA
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2018
·Vol. 185
·期 12
·1-9
·
IF 5.705
Wang Yongping,Yue Qiaoli,Tao Lixia,Zhang Cong,Li Chen-Zhong
N/S/P-codoped carbon dots (CDs) are shown to be a viable fluorescent probe in a turn-off-on fluorometric assay for hydroquinone (HQ). The preparation of CDs was carried out using a one-step hydrothermal reaction starting with glyoxal and isocarbophos. The method is based on the formation of ground state complexes between CD and Fe(III) which leads to quenching of blue fluorescence (with excitation/emission peaks at 363/448 nm). On addition of HQ, it will be oxidized by Fe(III) upon which fluorescence recovers. This turn-off-on system can be utilized to quantify HQ. A linear relationship exists between fluorescence recovery and HQ concentration in range between 0.56 and 375 μM. The limit of detection is 0.16 μM. The assay was successfully applied to the determination of HQ in spiked water samples and developer samples.
Fluorometric determination of hydroquinone (with good selectivity over catechol and resorcinol) by using blue-emitting N/S/P-codoped carbon dots and the quenching effect of Fe(III).
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2015
·
IF 7.435
Renfeng Nie,Meng Miao,Weichen Du,Juanjuan Shi,Yingchun Liu,Zhaoyin Hou
In this work, N-doped reduced graphene oxides (NRGO) was synthesized via a facile urea-hydrothermal treatment of graphene oxide and used as support for ultrafine Pd nanoparticles (NPs). It was found that N in NRGO can improve the dispersion of Pd NPs. NRGO supported Pd catalyst (Pd/NRGO) is highly active and selective for the hydrogenation of C C bond in cinnamaldehyde and hydrogenation of phenol to cyclohexanone under mild conditions. X-ray diffraction, X-ray photoelectron spectra and transmission electron microscopy characterizations confirmed the interaction between NRGO and Pd enhanced with the amount of N atom in NRGO. Raman spectroscopy of adsorbed cinnamaldehyde on Pd/NRGO suggested that NRGO played a positive role in the selective activation of C C bond in cinnamaldehyde.
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Artificial Cells Nanomedicine and Biotechnology
·
2014
·
IF 0
Meihao Liang,Xiaoliang Zheng,Linglan Tu,Zhen Ma,Zunyuan Wang,Dongmei Yan,Zhengrong Shen
In order to study the liver targeting of the N-galactosylated chitosan (GC) polymer in liver, we first conjugated the lactobionic acid with chitosan (CS) to obtain the carrier of GC with different degree of substitution of lactosyl group. Western blot was performed to detect the expression levels of the asialoglycoprotein receptors (ASGPR) in the cell lines of HepG2, SMMC-7721, and HL-7702. The protein level of ASGPR was lower in HepG2 compared to HL-7702 and SMMC-7721. Although all treated by CS, viabilities of HL-7702 and HepG2 did not experience any significant drop, while viability of SMMC-7721 decreased 15% on average from control. It was the first data about the inhibitory effect of GC on the liver cells. Fluorescein isothiocyanate (FITC) labeled GC (GC-FITC) was injected intravenously into mice at a dose of 0.02 μmol/mouse. GC-FITC showed maximum liver localization at 5 min and even detectable at 48 h after injection. Further, the accumulation of GC in liver was about 5.4-fold higher than that of CS. In conclusion, GC demonstrated its higher efficacy in drug liver targeting and thus could be a more promising drug or gene carrier in future therapies.
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MONATSHEFTE FUR CHEMIE
·
2014
·Vol. 145
·期 12
·1925-1931
·
IF 1.347
Tu Xingzhao,Zhou Lihong,Li Zhijie,Lei Ning,Zeng Qingle
Abstract The carbon-heteroatom bond formation is an important research field. Transition-metal-free synthesis of medicinally important heterocycles avoids products of transition metal contamination, and thus it is an environmentally friendly and cost-saving process. A transition-metal-free domino C-S/C-N formation for the synthesis of imidazobenzothiazines from 2-mercaptobenzimidazoles and 2-halobenzyl bromides is developed. The desired products were obtained in good to excellent yields. The mechanism of domino nucleophilic substitution (S N 2) and nucleophilic aromatic substitution (S N Ar) is proposed. Graphical abstract
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Nano Research
·
2014
·Vol. 7
·期 12
·1809-1819
·
IF 6.963
Han Chuanlong,Wang Shiping,Wang Jing,Li Mingming,Deng Jiang,Li Haoran,Wang Yong
Encompassing ecological and economic concerns, the utilization of biomass to produce carbonaceous materials has attracted intensive research and industrial interest. Using nitrogen containing precursors could realize an in situ and homogeneous incorporation of nitrogen into the carbonaceous materials with a controlled process. Herein, N-doped hollow core-disordered mesoporous shell carbonaceous nanospheres (HCDMSs) were synthesized from glucosamine hydrochloride (GAH), an applicable carbohydrate-based derivative. The obtained HCDMSs possessed controlled size (∼450-50 nm) and shell thickness (∼70-10 nm), suitable nitrogen contents (∼6.7-4.4 wt.%), and Brunauer-Emmett-Teller (BET) surface areas up to 770 m 2 ·g −1 . These materials show excellent electrocatalytic activity as a metal-free catalyst for the oxygen reduction reaction (ORR) in both alkaline and acidic media. Specifically, the prepared HCDMS-1 exhibits a high diffusion-limited current, and superior durability and better immunity towards methanol crossover and CO poisoning for ORR in alkaline solution than a commercial 20 wt.% Pt/C catalyst.
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RSC Advances
·
2015
·Vol. 5
·期 76
·62024-62032
·
IF 3.84
Qian Feng,Dongyan Tang,Haitao Lv,Weile Zhang,Wenbo Li
Well fabricated ZnO nanorods (ZnO NRs) arrays with preferred-orientation that grown on pre-deposited ZnO seed layers substrate were selected to graft thermo-responsive polymers of poly(N-isopropylacrylamide) (PNIPAM) by surface-initiated atom transfer radical polymerization (SI-ATRP). As a controlled/“living” radical polymerization, SI-ATRP could endow the systems with the characteristics of the grafted PNIPAM, meanwhile, with the maintaining of the properties of the ZnO NRs. The structures of ZnO and the grafted polymer with the relatively high molecular weights (Mn, 24 300) and narrow molecular weight distributions (Mw/Mn, 1.19) that determined by GPC detection, were characterized by XRD and FT-IR. The graft amount of PNIPAM on ZnO NRs and the interactions between the two components were determined by TG and XPS, respectively. The relatively thin layers of PNIPAM (∼15 nm) formed around NRs via SI-ATRP method were observed by SEM. And the temperature-sensitivity of the grafted nanorods were proved by contact angles measurements. Furthermore, photodegradation of Rhodamine B (Rh-B) by the grafted nanorods revealed that ZnO NRs–PNIPAM exhibited photocatalysis and temperature responsibility characteristics, indicating the significant potential applications with tunable responsiveness by changing the environmental conditions.
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ChemSusChem
·
2015
·Vol. 8
·期 15
·2487-2491
·
IF 7.657
Qun Li,Wei Cui,Jingqi Tian,Zhicai Xing,Qian Liu,Wei Xing,Abdullah M. Asiri,Xuping Sun
Graphical Who WON the race? N-Doped carbon-coated tungsten oxynitride nanowire arrays on carbon cloth (WON@NC NAs/CC) are prepared by annealing the WO 3 NAs/CC precursor under an Ar atmosphere in the presence of dicyandiamide and are used as a 3 D hydrogen evolution cathode with superior activity and stability over the pH 0–14 range. PBS=phosphate-buffered saline, RHE=reversible hydrogen electrode. It is highly desired but still challenging to develop active nonprecious metal hydrogen evolution reaction (HER) electrocatalysts operating under all pH conditions. Herein, the development of three-dimensional N-doped carbon-coated tungsten oxynitride nanowire arrays on carbon cloth as a highly efficient and durable HER cathode was explored. The material delivers current densities of 10 and 100 mA cm −2 at overpotentials of 106 and 172 mV, respectively, in acidic medium, and it also performs well in neutral and basic electrolytes.
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RSC Advances
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2015
·Vol. 5
·期 29
·22343-22349
·
IF 3.84
Zhao Chen,Xiaochi Wang,Hua Li,Chao Li,Qinghua Lu,Guang Yang,Jiangang Long,Lingjie Meng
A facile but effective bottom-up method for the mass preparation of N-doped carbon dots (N–C-dots) was developed by the direct heating of a solid mixture of folic acid (FA) and sodium citrate (SC) for several minutes at 300 °C. The nitrogen content of the resulting N–C-dots could be easily and precisely tuned from 0% to 14% by adjusting the SC to FA mass ratio. Uniform N–C-dots with honeycomb-like ordered structures were obtained, with sizes ranging from 1 to 3 nm in diameter. The N-doping content affected not only the emission quantum yield but also the emission wavelength. The N–C-dots emitted strong blue-green fluorescence based on the excitation wavelength and N-doping content. Because of their excellent water solubility, low toxicity, powerful fluorescence, and high resistance to photobleaching, the N–C-dots can enter various cells and serve as ideal candidates for multicolour cell imaging.
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Nanoscale
·
2015
·Vol. 7
·期 28
·11956-11961
·
IF 7.394
Wenxiu Yang,Xiaoyu Yue,Xiangjian Liu,Junfeng Zhai,Jianbo Jia
A highly efficient N, S co-doped porous carbon ORR catalyst was simply designed in our report from ordered mesoporous carbon (OMC) and trace ionic liquids (ILs). The microstructure OMC was chosen as the template for improving the specific area, confining the ILs in the mesopores, and promoting the formation of the planar N and S doping. The resulting IL/OMC (IOMC) nanostructure exhibits comparable ORR activity and better stability than the commercial Pt/C catalyst in 0.10 M KOH solution, which makes it one of the best-performing metal-free carbon ORR catalysts. We deduced that the excellent ORR activity is attributed to the synergistic effect of N, S, and the ordered mesoporous structure. Interestingly, the ORR activity can be further boosted in both basic and acidic solutions after Fe doping into the IOMC nanostructures which clearly emphasizes that transition metal Fe is important for the construction of ORR active functional sites especially in acidic solution.
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POLYMERS FOR ADVANCED TECHNOLOGIES
·
2014
·Vol. 25
·期 6
·684-688
·
IF 1.964
Chang Peng,Wu Pan,Lin Bao,Shu Chen,Yi Chen,Mingsong Han,Yuanqin Xiong,Weijian Xu
We report a facile method that combined sol–gel reaction, reversible addition–fragmentation chain transfer (RAFT)/macromolecular design via interchange of the xanthates process and thiol-ene click reaction to prepare monodisperse silica core-poly( N -vinylimidazole) (PVim) shell microspheres of 200 nm in average diameters. First, silica with C = C double bonds was prepared by the sol–gel reaction of 3-(trimethoxysilyl)propyl methacrylates (MPS) with tetraethoxysilane in ethanol; SiO 2 @PVim were subsequently prepared by grafting PVim chain (Mn = 9800 g/mol, polydispersity index = 1.22) to MPS-SiO 2 via the thiol-ene click chemisty. The obtained SiO 2 @PVim microspheres show higher catalytic activity toward the hydrolysis of p -nitrophenyl acetate compared with the PVim homopolymers. The as-prepared composites have been characterized by scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis and Fourier transform infrared spectrometry analysis. Copyright © 2014 John Wiley & Sons, Ltd.
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Nano Energy
·
2013
·
IF 0
Yan-Qing Zhang,De-Kun Ma,Yan-Ge Zhang,Wei Chen,Shao-Ming Huang
N-doped nanostructured carbon materials have attracted much attention because the doping can induce new unique physical and chemical properties of carbon. In this study, we report, for the first time, that N-doped carbon quantum dots (NCQDs) can combine with rutile TiO 2 and form NCQDs/TiO 2 hierarchical microspheres assembled by nanorods with enhanced photocatalytic activities under visible light irradiation. As a result, the pseudo-first-order reaction constant for the degradation of rhodamine B (RhB) on NCQDs/TiO 2 (0.11 min −1 ) is 215.7, 7.3 and 1.3 times much larger than that of NCQDs (0.00051 min −1 ), TiO 2 (0.015 min −1 ), and CQDs/TiO 2 (0.086 min −1 ), respectively. The functions of NCQDs were discussed and a new synergistic photosensitized mechanism was proposed for the degradation of RhB on the as-synthesized NCQDs/TiO 2 nanocomposites based on the experimental results. NCQDs were also applied as metal-free sensitizers in dye-sensitized solar cells (DSSCs) for the first time. A preliminary study shows that under one sun illumination (AM 1.5), the open circuit voltage and fill factor values reach 0.46 V and 43%, respectively, achieving a power conversion efficiency of 0.13% in the proof-of-concept TiO 2 -based DSSCs device. The performance of NCQDs sensitized solar cells surpasses that of N-free counterpart as well. N-doping lowered the work function of CQDs, which was responsible for enhanced photocatalytic activity of NCQDs/TiO 2 and better NCQDs sensitized TiO 2 -based solar cell performance.
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CARBOHYDRATE POLYMERS
·
2017
·
IF 4.811
Zehong Chen,Xinwen Peng,Xiaoting Zhang,Shuangshuang Jing,Linxin Zhong,Runcang Sun
Producing hierarchical porous N-doped carbon from renewable biomass is an essential and sustainable way for future electrochemical energy storage. Herein we cost-efficiently synthesized N-doped porous carbon from renewable cellulose by using urea as a low-cost N source, without any activation process. The as-prepared N-doped porous carbon (N-doped PC) had a hierarchical porous structure with abundant macropores, mesopores and micropores. The doping N resulted in more disordered structure, and the doping N content in N-doped PC could be easily tunable (0.68–7.64%). The doping N functionalities could significantly improve the supercapacitance of porous carbon, and even a little amount of doping N (e.g. 0.68%) could remarkably improve the supercapacitance. The as-prepared N-doped PC with a specific surface area of 471.7 m 2 g −1 exhibited a high specific capacitance of 193 F g −1 and a better rate capability, as well as an outstanding cycling stability with a capacitance retention of 107% after 5000 cycles. Moreover, the N-doped porous carbon had a high energy density of 17.1 W h kg −1 at a power density of 400 W kg −1 .
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