Bio based nitrogen doped carbon dots(N-CDs)were obtained from empty fruit bunch carboxymethylcellulose and ethylenediamine(EDA)through one-pot hydrothermal carbonization route.The optimum as-formed NCDs were thoroughl...Bio based nitrogen doped carbon dots(N-CDs)were obtained from empty fruit bunch carboxymethylcellulose and ethylenediamine(EDA)through one-pot hydrothermal carbonization route.The optimum as-formed NCDs were thoroughly characterized via Transmission electron microscopy(TEM),high-resolution TEM(HRTEM),Fourier transform infrared(FTIR),X-ray photoelectron spectra(XPS),UV–vis spectra(UV–Vis)and Fluorescence spectra(PL).Response surface methodology was statistically used to assess three independent variables that have major influence on the fluorescence quantum yield(QY),including temperature(230–270℃),time(2–6 h)and EDA mass(10%–23.3%).Based on analysis of variance(ANOVA)results,synthesis temperature was found to be the most influential factor on the QY,followed by time and EDA mass.Higher temperature,long synthesis time and high amount of EDA were satisfactorily enough for efficient carbonization conversion rate and obtaining highest QY of N-CDs.The obtained quadratic model(R^2=0.9991)shows a good correlation between the experimental data and predicted values.The optimum synthetic parameters are of 270℃temperature,6 h reaction time and 23.3%of EDA mass.The optimized as-made N-CDs exhibited blue photoluminescence with both excitation dependent/independent phenomena and high nitrogen content.The maximum emission intensity was 426 nm at a maximum excitation wavelength of 320 nm,with a QY of up to 22.9%.XPS and FTIR data confirmed the existence of polar containing groups,such as carbonyl,carboxyl,hydroxyl and amino groups over the surface of N-CDs whereas nitrogen species in the form of(pyridinic and graphitic-N)were introduced in the aromatic carbon domains,which imparts the hydrophilic and photostability of N-CDs.Taking into account the low-cost and sustainable production of N-CDs,this method considered a feasible route for converting low quality waste into value-added nanomaterials and utilizing for different functionalization processes and analytical applications.展开更多
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
基金Universiti Putra Malaysia for funding this project(GP-IPS/2017/9556800).
文摘Bio based nitrogen doped carbon dots(N-CDs)were obtained from empty fruit bunch carboxymethylcellulose and ethylenediamine(EDA)through one-pot hydrothermal carbonization route.The optimum as-formed NCDs were thoroughly characterized via Transmission electron microscopy(TEM),high-resolution TEM(HRTEM),Fourier transform infrared(FTIR),X-ray photoelectron spectra(XPS),UV–vis spectra(UV–Vis)and Fluorescence spectra(PL).Response surface methodology was statistically used to assess three independent variables that have major influence on the fluorescence quantum yield(QY),including temperature(230–270℃),time(2–6 h)and EDA mass(10%–23.3%).Based on analysis of variance(ANOVA)results,synthesis temperature was found to be the most influential factor on the QY,followed by time and EDA mass.Higher temperature,long synthesis time and high amount of EDA were satisfactorily enough for efficient carbonization conversion rate and obtaining highest QY of N-CDs.The obtained quadratic model(R^2=0.9991)shows a good correlation between the experimental data and predicted values.The optimum synthetic parameters are of 270℃temperature,6 h reaction time and 23.3%of EDA mass.The optimized as-made N-CDs exhibited blue photoluminescence with both excitation dependent/independent phenomena and high nitrogen content.The maximum emission intensity was 426 nm at a maximum excitation wavelength of 320 nm,with a QY of up to 22.9%.XPS and FTIR data confirmed the existence of polar containing groups,such as carbonyl,carboxyl,hydroxyl and amino groups over the surface of N-CDs whereas nitrogen species in the form of(pyridinic and graphitic-N)were introduced in the aromatic carbon domains,which imparts the hydrophilic and photostability of N-CDs.Taking into account the low-cost and sustainable production of N-CDs,this method considered a feasible route for converting low quality waste into value-added nanomaterials and utilizing for different functionalization processes and analytical applications.
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.
