Microwave-induced nitrogen-doped titanate nanotubes（NTNTs） were characterized by transmission electron microscopy（TEM）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, Fourier transform infrared...Microwave-induced nitrogen-doped titanate nanotubes（NTNTs） were characterized by transmission electron microscopy（TEM）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, Fourier transform infrared spectroscopy（FT-IR）, Zeta potential analysis,specific surface area（SBET）, and UV-Visible spectroscopy. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti-O-N linkage observed in the XPS N 1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. FT-IR results demonstrated the existence of H3O＋, which could be excited by photo-generated holes to form hydroxyl radicals and degrade environmental pollutants. After sintering at 350°C, the UV-Vis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic degradation of Rhodamine B（RhB） via NTNTs show good efficiency, with pseudo first-order kinetic model rate constants of 3.7 × 10-3, 2.4 × 10-3and 8.0 × 10-4sec-1at pH 3, 7, and 11, respectively.展开更多
This study employed microwave-assisted hydrothermal method to synthesize Ti-MCM-41,which are mesoporous materials with a high surface area and excellent photocatalytic ability. Fourier transform infrared spectroscopy...This study employed microwave-assisted hydrothermal method to synthesize Ti-MCM-41,which are mesoporous materials with a high surface area and excellent photocatalytic ability. Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, transmission electron microscopy（TEM）, and ultraviolet–visible spectroscopy（UV–Vis） were employed. The XRD findings showed that Ti-MCM-41 exhibited a peak at 2θ of 2.2°, which was attributed to the hexagonal MCM-41 structure. The BET（Brunauer–Emmett–Teller） results agreed with the TEM findings that Ti-MCM-41 has a pore size of about 3–5 nm and a high surface area of 883 m-2/g. FTIR results illustrated the existence of Si–O–Si and Si–O–Ti bonds in Ti-MCM-41. The appearance of Ti2 p peaks in the XPS results confirmed the FTIR findings that the Ti was successfully doped into the MCM-41 structure. Zeta（ζ）-potential results indicated that the iso-electric point（IEP） of Ti-MCM-41 was at about pH 3.02. In this study, the photocatalytic degradation of oxytetracycline（OTC） at different pH was investigated under Hg lamp irradiation（wavelength 365 nm）. The rate constant（K′obs） for OTC degradation was 0.012 min-1at pH 3. Furthermore, TOC（total organic carbon） and high resolution LC–MS（liquid chromatography–mass spectrometry） analyses were conducted to elucidate the possible intermediate products and degradation pathway for OTC. The TOC removal efficiency of OTC degradation was 87.0%, 74.4% and 50.9% at pH 3, 7 and 10, respectively. LC–MS analysis results showed that the degradation products from OTC resulted from the removal of functional groups from the OTC ring.展开更多
Several methods have been used to tailor nanomaterials structure and properties.Sometimes,slight changes in the structure outcomes expressive improvements in the optical and photocatalytic properties of semiconductor ...Several methods have been used to tailor nanomaterials structure and properties.Sometimes,slight changes in the structure outcomes expressive improvements in the optical and photocatalytic properties of semiconductor nanoparticles.In this context,the influence of the metal doping and the morphology on a catalyst performance was studied in this work.Here,ruthenium doped titanate nanotubes(RuTNT)were synthesised for the first time using an amorphous Ru-containing precursor.Afterwards,the photocatalytic performance of this sample was compared to the one obtained for ruthenium titanate nanowires(RuTNW),recently reported.Two samples,RuTNW and RuTNT,were produced using the same Ru-containing precursor but distinct hydrothermal methodologies.The powders were structural,morphological and optical characterized by X-ray diffraction and fluorescence,transmission electron microscopy,Raman,X-ray photoelectron and photoluminescence spectroscopies.Distinct variations on the structural and optical properties of the RuTNT and RuTNW nanoparticles,due to ruthenium incorporation were observed.Their potential use as photocatalysts was evaluated on the hydroxyl radical photo-assisted production.Both samples were catalytic for this reaction,presenting better performances than the pristine counterparts,being RuTNT the best photocatalyst.Subsequently,the degradation of two emergent pollutants,caffeine and sulfamethazine,was studied.RuTNT demonstrated to be better photocatalyst than RuTNW for caffeine but identical performances were obtained for sulfamethazine.For both catalysts,the degradation mechanism of the pollutants was explored through the identification and quantification of the intermediate compounds produced and several differences were found.This indicates the importance of the structural and morphological aspects of a material on its catalytic performance.展开更多
采用水热法制备了稀土元素钕掺杂的钛酸钡与碳纳米管（CNTs）的复合吸波材料。利用红外光谱（IR）、X-射线衍射仪（XRD）及能谱仪（EDS）测试了样品的结构与成分,并采用透射电子显微镜（TEM）对样品的形貌进行了表征。考察了Nd掺杂及不...采用水热法制备了稀土元素钕掺杂的钛酸钡与碳纳米管（CNTs）的复合吸波材料。利用红外光谱（IR）、X-射线衍射仪（XRD）及能谱仪（EDS）测试了样品的结构与成分,并采用透射电子显微镜（TEM）对样品的形貌进行了表征。考察了Nd掺杂及不同的CNTs复合量对复合材料在低频区（0-6 000 MHz）吸波性能的影响。结果表明,Nd掺杂后钛酸钡的吸波性能得到一定的提升,随着CNTs复合量的增加,吸收峰的位置先向低频移动后又移向高频。当CNTs含量为7%时,复合材料在频率为4 270.8 MHz处出现了-13.5 d B的最强吸收峰,〈-5 d B的频宽达520.8 MHz。展开更多
文摘Microwave-induced nitrogen-doped titanate nanotubes（NTNTs） were characterized by transmission electron microscopy（TEM）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, Fourier transform infrared spectroscopy（FT-IR）, Zeta potential analysis,specific surface area（SBET）, and UV-Visible spectroscopy. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti-O-N linkage observed in the XPS N 1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. FT-IR results demonstrated the existence of H3O＋, which could be excited by photo-generated holes to form hydroxyl radicals and degrade environmental pollutants. After sintering at 350°C, the UV-Vis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic degradation of Rhodamine B（RhB） via NTNTs show good efficiency, with pseudo first-order kinetic model rate constants of 3.7 × 10-3, 2.4 × 10-3and 8.0 × 10-4sec-1at pH 3, 7, and 11, respectively.
基金financial support provided by the Tunghai University Global Research and Education on Environment and Society (No. 103GREEnS 005-2)
文摘This study employed microwave-assisted hydrothermal method to synthesize Ti-MCM-41,which are mesoporous materials with a high surface area and excellent photocatalytic ability. Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, transmission electron microscopy（TEM）, and ultraviolet–visible spectroscopy（UV–Vis） were employed. The XRD findings showed that Ti-MCM-41 exhibited a peak at 2θ of 2.2°, which was attributed to the hexagonal MCM-41 structure. The BET（Brunauer–Emmett–Teller） results agreed with the TEM findings that Ti-MCM-41 has a pore size of about 3–5 nm and a high surface area of 883 m-2/g. FTIR results illustrated the existence of Si–O–Si and Si–O–Ti bonds in Ti-MCM-41. The appearance of Ti2 p peaks in the XPS results confirmed the FTIR findings that the Ti was successfully doped into the MCM-41 structure. Zeta（ζ）-potential results indicated that the iso-electric point（IEP） of Ti-MCM-41 was at about pH 3.02. In this study, the photocatalytic degradation of oxytetracycline（OTC） at different pH was investigated under Hg lamp irradiation（wavelength 365 nm）. The rate constant（K′obs） for OTC degradation was 0.012 min-1at pH 3. Furthermore, TOC（total organic carbon） and high resolution LC–MS（liquid chromatography–mass spectrometry） analyses were conducted to elucidate the possible intermediate products and degradation pathway for OTC. The TOC removal efficiency of OTC degradation was 87.0%, 74.4% and 50.9% at pH 3, 7 and 10, respectively. LC–MS analysis results showed that the degradation products from OTC resulted from the removal of functional groups from the OTC ring.
基金Fundacao para a Ciencia e Tecnologia(FCT)(projects PEst-OE/QUI/QUI0612/2019 and IF/01210/2014)CICECO-Aveiro Institute of Materials(project POCI-01-0145FEDER-007679)financed by national funds through the FCT/MEC+2 种基金appropriate cofinanced by FEDER(Fundo Europeu de Desenvolvimento Regional)under the PT2020 Partnership AgreementFCT for her grant(No.SFRH/BD/101220/2014)funded by national funds(OE),through FCT。
文摘Several methods have been used to tailor nanomaterials structure and properties.Sometimes,slight changes in the structure outcomes expressive improvements in the optical and photocatalytic properties of semiconductor nanoparticles.In this context,the influence of the metal doping and the morphology on a catalyst performance was studied in this work.Here,ruthenium doped titanate nanotubes(RuTNT)were synthesised for the first time using an amorphous Ru-containing precursor.Afterwards,the photocatalytic performance of this sample was compared to the one obtained for ruthenium titanate nanowires(RuTNW),recently reported.Two samples,RuTNW and RuTNT,were produced using the same Ru-containing precursor but distinct hydrothermal methodologies.The powders were structural,morphological and optical characterized by X-ray diffraction and fluorescence,transmission electron microscopy,Raman,X-ray photoelectron and photoluminescence spectroscopies.Distinct variations on the structural and optical properties of the RuTNT and RuTNW nanoparticles,due to ruthenium incorporation were observed.Their potential use as photocatalysts was evaluated on the hydroxyl radical photo-assisted production.Both samples were catalytic for this reaction,presenting better performances than the pristine counterparts,being RuTNT the best photocatalyst.Subsequently,the degradation of two emergent pollutants,caffeine and sulfamethazine,was studied.RuTNT demonstrated to be better photocatalyst than RuTNW for caffeine but identical performances were obtained for sulfamethazine.For both catalysts,the degradation mechanism of the pollutants was explored through the identification and quantification of the intermediate compounds produced and several differences were found.This indicates the importance of the structural and morphological aspects of a material on its catalytic performance.
基金supported by the Key Laboratory of Preparation and Application Environmentally Friendly Materials of the Ministry of Education of ChinaScientific Research Innovation Plan for Young Talented Person and Plans of Scientific Research Innovation for Postgraduates of Jilin Normal University,China~~
文摘采用水热法制备了稀土元素钕掺杂的钛酸钡与碳纳米管（CNTs）的复合吸波材料。利用红外光谱（IR）、X-射线衍射仪（XRD）及能谱仪（EDS）测试了样品的结构与成分,并采用透射电子显微镜（TEM）对样品的形貌进行了表征。考察了Nd掺杂及不同的CNTs复合量对复合材料在低频区（0-6 000 MHz）吸波性能的影响。结果表明,Nd掺杂后钛酸钡的吸波性能得到一定的提升,随着CNTs复合量的增加,吸收峰的位置先向低频移动后又移向高频。当CNTs含量为7%时,复合材料在频率为4 270.8 MHz处出现了-13.5 d B的最强吸收峰,〈-5 d B的频宽达520.8 MHz。
