The nitrogen-doped carbon dots(N-CDs)were prepared by using coke powder as carbon source and one-step hydrothermal method.The N-CDs were studied as a fluorescent chemosensor for determining Cr(Ⅵ)in water.The selectiv...The nitrogen-doped carbon dots(N-CDs)were prepared by using coke powder as carbon source and one-step hydrothermal method.The N-CDs were studied as a fluorescent chemosensor for determining Cr(Ⅵ)in water.The selective,sensitive,reproducibility and stability of as-prepared N-CDs were investigated.The morphology,composition and properties of N-CDs were characterized by a series of methods.The fluorescence quenching of N-CDs by Cr(Ⅵ)was explored.The experimental results reveal that the obtained N-CDs have great hydrophilicity and strong luminescence properties,which demonstrates the successful doping of nitrogen into the CDs.The surface-active groups and emission wavelength range of CDs increase due to the electronegativity and electron donor effect of doping N atom.Furthermore,the N-CDs exhibit good photochemical properties for the detection of Cr(Ⅵ),including a wide linear range from 0.3 to 200μM(R^(2)=0.9935)and a low detection limit of 0.10μM at the signal-to-noise ratio of 3(S/N=3).Moreover,the N-CDs as a sensor was used successfully for Cr(Ⅵ)detection in real water samples with recovery rates of 99.9%-110.6%.This sensor also shows highly reproducibility and stability.The N-CDs fluorescent chemical sensor may be a potential candidate for applying in the field of other fluorescent chemical sensing,catalysis,photoelectric devices and other fields.展开更多
Terephthalic acid,2,5-furandicarboxylic acid and 1,8-octanediol were adopted as monomers and antimony trioxide as catalyst,and poly(terephthalic acid-2,5-furandicarboxylic acid-1,8-octanediol) copolyesters identified ...Terephthalic acid,2,5-furandicarboxylic acid and 1,8-octanediol were adopted as monomers and antimony trioxide as catalyst,and poly(terephthalic acid-2,5-furandicarboxylic acid-1,8-octanediol) copolyesters identified as PEOT-x,where x is the mole fraction of furandicarboxylic acid in the samples,were synthesized by direct esterification.The molecular structure of the copolyesters was characterized by FTIR and 1H NMR spectroscopy.Gel permeation chromatography (GPC),differential scanning calorimetry (DSC),and thermogravimetric analysis (TGA) were used to characterize the molecular weight,molar mass dispersity,glass transition temperature,and thermal stability of the copolyesters,respectively.The mechanical properties of the samples were also investigated.The number-average molecular weight (M_(n)) of the samples varies from 9 700-18 800 g/mol,and molar mass dispersity (■=M_(w)/M_(n)) from 2.15-3.34.The initial decomposition temperature of the copolyesters is in the 332-356 ℃ range,with maximum decomposition rates at 390-410 ℃,while the glass transition temperature (Tg) varies from 0-33 ℃.Mechanical test shows that PEOT-10 has the highest tensile strength,while PEOT-90 has the largest tensile modulus and elongation at break.The experimental results show that these copolyesters can be synthesized with relatively high molecular weights,good thermal stability,and fair mechanical properties,which makes them excellent replacements for commercial polyesters,such as PET,and these properties can be tuned through the relative amounts of biomass monomer 2,5-furandicarboxylic acid used in the reactions.展开更多
The thioglycollic acid（TGA） as a capping agent, CdTe/TGA quantum dots（QDs） with excellent properties were synthesized under microwave irradiation. The TGA/Cd/Te molar ratios, reaction time, temperature and p H are...The thioglycollic acid（TGA） as a capping agent, CdTe/TGA quantum dots（QDs） with excellent properties were synthesized under microwave irradiation. The TGA/Cd/Te molar ratios, reaction time, temperature and p H are the crucial factors for properties of QDs. The QDs were characterized by UVvis absorption and fluorescence spectra, transmission electron microscopy and Fourier transform infrared spectroscopy. The experimental results show that when the p H value is 11.5 and molar ratio of TGA：Cd：Te is 1.2：1：0.4 at 100 ℃ heating for 15 min, the resulted QDs exhibit a high fluorescence quantum yield of 78%. The fluorescence full width at half maximum（FHMW） of QDs is around 23 nm. The products are spherical with average size of 3-5 nm. There is a strong coordination effect between TGA and Cd2＋. Moreover, the results of interaction between as-made QDs and bovine serum albumin（BSA） suggest that the QDs-BSA binding reaction is a static quenching. The negative values of free energy（△G〈0） suggest that the binding process is spontaneous, △H〈0 and △S〈0 show that hydrogen bonds and van der Waals interactions play a major role in the binding reaction between QDs and BSA.展开更多
A new kind of zirconium（Zr） complex containing ligand of salicylaldehyde-imine was successfully synthesized with ZrCl_4·2 THF and salicylaldehyde-imine as raw materials. The ligand was characterized by means of...A new kind of zirconium（Zr） complex containing ligand of salicylaldehyde-imine was successfully synthesized with ZrCl_4·2 THF and salicylaldehyde-imine as raw materials. The ligand was characterized by means of ~1HNMR, IR, and GC-MS, and Zr complex was characterized by means of ~1HNMR and IR, respectively. The Zr complex, combined with co-catalyst of Al（i-Bu）_3, was explored to be effective catalytic system for the polymerization of butyl methacrylate（BMA）, to prepare poly-n-butyl methacrylate（PBMA）, which was characterized by IR, ~13C-NMR and GPC. Compared with other double-component（MAO/Cat, AlEt_3/Cat） catalytic systems, catalytic system of Al（i-Bu）_3 and the Zr complex provided the best catalytic activity under the same conditions. The influence of polymerization parameters, such as molar ratio of Al（i-Bu）_3/Cat and BMA/Cat, polymerization temperature and polymerization time, was studied with Zr complex/Al（i-Bu）_3 system. With increasing polymerization time from 4 to 24 hour, the monomer conversion increased from 40.14% to 96.56%. Viscosity-average molecular weight（M_v） of PBMA, detected by the viscosity methodology, increased from 12.67×10~4Da to 44.97×10~4Da and lower molecular weight distribution was obtained. According to these results, the Zr complex contained ligand of salicylaldehyde-imine was a kind of readily, long lifetime and high activity catalyst for BMA polymerization.展开更多
High molecular weight poly(1,4-butylene 2,5-furandicarboxylate-co-isosorbide 2,5-furandicarboxylate)copolyesters(PBSIF-x)were synthesized via melt-polycondensation of 2,5-furandicarboxylic acid(FDCA),with varying rati...High molecular weight poly(1,4-butylene 2,5-furandicarboxylate-co-isosorbide 2,5-furandicarboxylate)copolyesters(PBSIF-x)were synthesized via melt-polycondensation of 2,5-furandicarboxylic acid(FDCA),with varying ratios of isosorbide(ISB)and 1,4-butylene glycol(BDO)catalyzed by antimony trioxide(Sb_(2)O_(3)).The PBSIF-x structures were investigated using FTIR and~1H NMR,while the GPC analysis exhibited the copolyesters molecular weights with number average molecular mass(M_n)in the range of 11079-15153 g/mol.The DSC results show that PBSIF-x copolyesters have a single glass-transition temperature(T_(g))(77.45-110.96℃),increasing with the increase in ISB content,while TGA analysis demonstrates excellent thermal stability up to 320℃.From the thermal result,properties of PBSIF-x copolyesters are found to be within the interval of their parent homologues poly(butylene 2,5-furandicarboxylate)(PBF)and poly(isosorbide 2,5-furandicarboxylate)(PIF),which confirms the aromatic/aliphatic blending within the polymer matrix for enhanced polymer stability and performance.展开更多
基金by the National Nature Science Foundation of China(61904130)the Open Fund of the Fujian Universities and Colleges Engineering Research Center of Modern Facility Agriculture of Fujian University(G2-KF2002)+4 种基金the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education,Jianghan University(JDGD202017)the Open Fund of the Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steel Making(Wuhan University of Science and Technology)of China(KF-20-5)the Fund of Hangzhou Meishi Technology Co.,Ltd of China(2021420112000081)the Key Research and Development Program of Hubei Province(2020BAB084)the Program(BG20190227001)of High-end Foreign Experts of the State of the State Administration of Foreign Experts Affairs(SAFEA)。
文摘The nitrogen-doped carbon dots(N-CDs)were prepared by using coke powder as carbon source and one-step hydrothermal method.The N-CDs were studied as a fluorescent chemosensor for determining Cr(Ⅵ)in water.The selective,sensitive,reproducibility and stability of as-prepared N-CDs were investigated.The morphology,composition and properties of N-CDs were characterized by a series of methods.The fluorescence quenching of N-CDs by Cr(Ⅵ)was explored.The experimental results reveal that the obtained N-CDs have great hydrophilicity and strong luminescence properties,which demonstrates the successful doping of nitrogen into the CDs.The surface-active groups and emission wavelength range of CDs increase due to the electronegativity and electron donor effect of doping N atom.Furthermore,the N-CDs exhibit good photochemical properties for the detection of Cr(Ⅵ),including a wide linear range from 0.3 to 200μM(R^(2)=0.9935)and a low detection limit of 0.10μM at the signal-to-noise ratio of 3(S/N=3).Moreover,the N-CDs as a sensor was used successfully for Cr(Ⅵ)detection in real water samples with recovery rates of 99.9%-110.6%.This sensor also shows highly reproducibility and stability.The N-CDs fluorescent chemical sensor may be a potential candidate for applying in the field of other fluorescent chemical sensing,catalysis,photoelectric devices and other fields.
基金Funded by the Program (BG20190227001) of High-end Foreign Experts of the State Administration of Foreign Experts Affairs (SAFEA)the 2021 Innovative Training Program for College Students in Hubei Province。
文摘Terephthalic acid,2,5-furandicarboxylic acid and 1,8-octanediol were adopted as monomers and antimony trioxide as catalyst,and poly(terephthalic acid-2,5-furandicarboxylic acid-1,8-octanediol) copolyesters identified as PEOT-x,where x is the mole fraction of furandicarboxylic acid in the samples,were synthesized by direct esterification.The molecular structure of the copolyesters was characterized by FTIR and 1H NMR spectroscopy.Gel permeation chromatography (GPC),differential scanning calorimetry (DSC),and thermogravimetric analysis (TGA) were used to characterize the molecular weight,molar mass dispersity,glass transition temperature,and thermal stability of the copolyesters,respectively.The mechanical properties of the samples were also investigated.The number-average molecular weight (M_(n)) of the samples varies from 9 700-18 800 g/mol,and molar mass dispersity (■=M_(w)/M_(n)) from 2.15-3.34.The initial decomposition temperature of the copolyesters is in the 332-356 ℃ range,with maximum decomposition rates at 390-410 ℃,while the glass transition temperature (Tg) varies from 0-33 ℃.Mechanical test shows that PEOT-10 has the highest tensile strength,while PEOT-90 has the largest tensile modulus and elongation at break.The experimental results show that these copolyesters can be synthesized with relatively high molecular weights,good thermal stability,and fair mechanical properties,which makes them excellent replacements for commercial polyesters,such as PET,and these properties can be tuned through the relative amounts of biomass monomer 2,5-furandicarboxylic acid used in the reactions.
基金Funded by the China Scholarship Council and Hubei Provincial Department of Education of China(201308420539)the Science and Technology Research Program of Hubei Provincial Department of Education of China(Q20131105,B2016008)+1 种基金the Coal Conversion and New Carbon Materials Hubei Key Laboratory(Wuhan University of Science and Technology(WKDM201505,WKDM201507)the Wuhan University of Science and Technology Foundation of China(z00980,2014XG006)
文摘The thioglycollic acid（TGA） as a capping agent, CdTe/TGA quantum dots（QDs） with excellent properties were synthesized under microwave irradiation. The TGA/Cd/Te molar ratios, reaction time, temperature and p H are the crucial factors for properties of QDs. The QDs were characterized by UVvis absorption and fluorescence spectra, transmission electron microscopy and Fourier transform infrared spectroscopy. The experimental results show that when the p H value is 11.5 and molar ratio of TGA：Cd：Te is 1.2：1：0.4 at 100 ℃ heating for 15 min, the resulted QDs exhibit a high fluorescence quantum yield of 78%. The fluorescence full width at half maximum（FHMW） of QDs is around 23 nm. The products are spherical with average size of 3-5 nm. There is a strong coordination effect between TGA and Cd2＋. Moreover, the results of interaction between as-made QDs and bovine serum albumin（BSA） suggest that the QDs-BSA binding reaction is a static quenching. The negative values of free energy（△G〈0） suggest that the binding process is spontaneous, △H〈0 and △S〈0 show that hydrogen bonds and van der Waals interactions play a major role in the binding reaction between QDs and BSA.
基金Funded by the Natural Science Foundation of Hubei Province(2017CFB680)the Excellent Youth Project of Hubei Provincial Department of Education(Q20162806)+1 种基金the National Undergraduate Science Foundation of China(No.201510488004)the Open Foundation of Hubei Province Key Laboratory of Coal Conversion and Novel Materials(WKDM201509)
文摘A new kind of zirconium（Zr） complex containing ligand of salicylaldehyde-imine was successfully synthesized with ZrCl_4·2 THF and salicylaldehyde-imine as raw materials. The ligand was characterized by means of ~1HNMR, IR, and GC-MS, and Zr complex was characterized by means of ~1HNMR and IR, respectively. The Zr complex, combined with co-catalyst of Al（i-Bu）_3, was explored to be effective catalytic system for the polymerization of butyl methacrylate（BMA）, to prepare poly-n-butyl methacrylate（PBMA）, which was characterized by IR, ~13C-NMR and GPC. Compared with other double-component（MAO/Cat, AlEt_3/Cat） catalytic systems, catalytic system of Al（i-Bu）_3 and the Zr complex provided the best catalytic activity under the same conditions. The influence of polymerization parameters, such as molar ratio of Al（i-Bu）_3/Cat and BMA/Cat, polymerization temperature and polymerization time, was studied with Zr complex/Al（i-Bu）_3 system. With increasing polymerization time from 4 to 24 hour, the monomer conversion increased from 40.14% to 96.56%. Viscosity-average molecular weight（M_v） of PBMA, detected by the viscosity methodology, increased from 12.67×10~4Da to 44.97×10~4Da and lower molecular weight distribution was obtained. According to these results, the Zr complex contained ligand of salicylaldehyde-imine was a kind of readily, long lifetime and high activity catalyst for BMA polymerization.
基金Funded by the Program(BG2021)of High-end Foreign Experts of The State Administration of Foreign Experts Affairs(SAFEA)the Young Talent Project of Hubei Provincial Department of Education,China(No.Q20201108)。
文摘High molecular weight poly(1,4-butylene 2,5-furandicarboxylate-co-isosorbide 2,5-furandicarboxylate)copolyesters(PBSIF-x)were synthesized via melt-polycondensation of 2,5-furandicarboxylic acid(FDCA),with varying ratios of isosorbide(ISB)and 1,4-butylene glycol(BDO)catalyzed by antimony trioxide(Sb_(2)O_(3)).The PBSIF-x structures were investigated using FTIR and~1H NMR,while the GPC analysis exhibited the copolyesters molecular weights with number average molecular mass(M_n)in the range of 11079-15153 g/mol.The DSC results show that PBSIF-x copolyesters have a single glass-transition temperature(T_(g))(77.45-110.96℃),increasing with the increase in ISB content,while TGA analysis demonstrates excellent thermal stability up to 320℃.From the thermal result,properties of PBSIF-x copolyesters are found to be within the interval of their parent homologues poly(butylene 2,5-furandicarboxylate)(PBF)and poly(isosorbide 2,5-furandicarboxylate)(PIF),which confirms the aromatic/aliphatic blending within the polymer matrix for enhanced polymer stability and performance.
