The performance of Mn-TiO2/sepiolite photocatalysts prepared by the solgel method and calcinated at different temperatures was studied in the photocatalytic degradation of direct fast emerald green dye under visible l...The performance of Mn-TiO2/sepiolite photocatalysts prepared by the solgel method and calcinated at different temperatures was studied in the photocatalytic degradation of direct fast emerald green dye under visible light irradiation,and a series of analytical techniques such as XRD,SEM,FTIR,TG-DSC,XPS,UV-vis-DRS and Raman spectroscopy were used to characterize the morphology,structure and optical properties of the photocatalysts.It is found that the anatase TiO2 was formed in all photocatalysts.Mn4+might incorporate into the lattice structure of TiO2 and partially replace Ti4+,thus causing the defects in the crystal structure and the broadening of the spectral response range of TiO2.At the same time,TiO2 particles were dispersed on the surface of the sepiolite,which immobilized TiO2 particles with sepiolite via the bond of Ti-O-Si.Mn-TiO2/sepiolite calcined at 400°C exhibits the highest photocatalytic activity and the degradation rate of direct fast emerald green is up to 98.13%.Meanwhile,it also shows good stability and universality.展开更多
A facile and reproducible method has been developed for the synthesis of ordered anatase Mn-TiO2 nanospheres with controllable sizes in the range 200-300 nm by simply varying the amount of manganese（lI） chloride add...A facile and reproducible method has been developed for the synthesis of ordered anatase Mn-TiO2 nanospheres with controllable sizes in the range 200-300 nm by simply varying the amount of manganese（lI） chloride added. The samples were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscope （SEM）, and transmission electron microscope （TEM） measurements, and it was found that the manganese exists in multivalent forms （Mn4＋/Mn3＋） and substitutes for some of the Ti4＋ in the anatase TiO2 lattice. The presence of Mn significantly influences the morphology and high-temperature stability of TiO2, and extends its light absorption range. Surface photovoltage and photocurrent measurements revealed that an electronic interaction between the Mn and TiO2 was present, in which Mn served as an electron acceptor and effectively inhibited the charge recombination in TiO2; this is thought to be responsible for the highly efficient photocatalytic activity of the material in the degradation of rhodarnine B （RhB） under visible-light irradiation （λ 〉 420 nm）.展开更多
The TiO2-Mn-TiO2multilayers are successfully grown on glass and silicon substrates by alternately using radio frequency reactive magnetron sputtering and direct current magnetron sputtering. The structures and the mag...The TiO2-Mn-TiO2multilayers are successfully grown on glass and silicon substrates by alternately using radio frequency reactive magnetron sputtering and direct current magnetron sputtering. The structures and the magnetic behaviours of these films are characterised with x-ray diffraction, transmission electron microscope （TEM）, vibrating sample magnetometer, and superconducting quantum interference device （SQUID）. It is shown that the multi-film consists of a mixture of anatase and rutile TiO2 with an embedded Mn nano-film. It is found that there are two turning points from ferromagnetic phase to antiferromagnetic phase. One is at 42 K attributed to interface coupling between ferromagnetic Mn3O4 and antiferromagnetic Mn2O3, and the other is at 97 K owing to the interface coupling between ferromagnetic Mn and antiferromagnetic MnO. The samples are shown to have ferromagnetic behaviours at room temperature from hysteresis in the M-H loops, and their ferromagnetism is found to vary with the thickness of Mn nano-film. Moreover, the Mn nano-film has a critical thickness of about 18.5 nm, which makes the coercivity of the multi-film reach a maximum of about 3.965 × 10^-2 T.展开更多
[Objective] The study aimed to extract fulvic acid from brown coal using N-Mn-TiO2 as a catalyst and H2O2 or HNO3 as an oxidizer. [Method] The effects of catalyst N-Mn-TiO2 on the yield and structure of fuMc acid were...[Objective] The study aimed to extract fulvic acid from brown coal using N-Mn-TiO2 as a catalyst and H2O2 or HNO3 as an oxidizer. [Method] The effects of catalyst N-Mn-TiO2 on the yield and structure of fuMc acid were studied, and the content of functional groups in fulvic acid was analyzed qualitatively and quantitatively. [ Reselt] Two catalysts could improved the yield of fulvic acid, that is, catalyst 1 （N： Mn： 13 = 16： 0.001：1, roasting temperature was 400 ℃） and catalyst 2 （N： Mn： Ti = 16： 0.001：1, roasting temperature was 100 ℃） increased OFA yield by 10.69% and 32.17% and NFA by 8.61% and 7.49% respectively. After the addition of catalysts, the content of total acid radicals in OFA changed little, and carboxyi content increased slightly, but phenolic hydroxyl content decreased. When HNO3 was used as an oxidizer, the content of total acid radicals and phenolic hydroxyl in NFA decreased. In addition, the structure of OFA was different from that of NFA. [Condusion] The research could provide scientific references for the development and application of brown coal in future.展开更多
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China(Grant No.21406184)the Foundation of Youth Science and Technology Innovation Team of Sichuan Province(Grant No.2015TD0007).
文摘The performance of Mn-TiO2/sepiolite photocatalysts prepared by the solgel method and calcinated at different temperatures was studied in the photocatalytic degradation of direct fast emerald green dye under visible light irradiation,and a series of analytical techniques such as XRD,SEM,FTIR,TG-DSC,XPS,UV-vis-DRS and Raman spectroscopy were used to characterize the morphology,structure and optical properties of the photocatalysts.It is found that the anatase TiO2 was formed in all photocatalysts.Mn4+might incorporate into the lattice structure of TiO2 and partially replace Ti4+,thus causing the defects in the crystal structure and the broadening of the spectral response range of TiO2.At the same time,TiO2 particles were dispersed on the surface of the sepiolite,which immobilized TiO2 particles with sepiolite via the bond of Ti-O-Si.Mn-TiO2/sepiolite calcined at 400°C exhibits the highest photocatalytic activity and the degradation rate of direct fast emerald green is up to 98.13%.Meanwhile,it also shows good stability and universality.
基金This work was supported by National Program on Key Basic Research Project （973 Program） （No. 2007CB613303） and the National Natural Science Foundation of China （Nos. 20703020 and 20873053）.
文摘A facile and reproducible method has been developed for the synthesis of ordered anatase Mn-TiO2 nanospheres with controllable sizes in the range 200-300 nm by simply varying the amount of manganese（lI） chloride added. The samples were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscope （SEM）, and transmission electron microscope （TEM） measurements, and it was found that the manganese exists in multivalent forms （Mn4＋/Mn3＋） and substitutes for some of the Ti4＋ in the anatase TiO2 lattice. The presence of Mn significantly influences the morphology and high-temperature stability of TiO2, and extends its light absorption range. Surface photovoltage and photocurrent measurements revealed that an electronic interaction between the Mn and TiO2 was present, in which Mn served as an electron acceptor and effectively inhibited the charge recombination in TiO2; this is thought to be responsible for the highly efficient photocatalytic activity of the material in the degradation of rhodarnine B （RhB） under visible-light irradiation （λ 〉 420 nm）.
基金supported by the Innovation Foundation of Beijing University of Aeronautics and Astronautics for PhD Graduates,China(Grant No.292122)the Equipment Research Foundation of China (Grant No.373974)
文摘The TiO2-Mn-TiO2multilayers are successfully grown on glass and silicon substrates by alternately using radio frequency reactive magnetron sputtering and direct current magnetron sputtering. The structures and the magnetic behaviours of these films are characterised with x-ray diffraction, transmission electron microscope （TEM）, vibrating sample magnetometer, and superconducting quantum interference device （SQUID）. It is shown that the multi-film consists of a mixture of anatase and rutile TiO2 with an embedded Mn nano-film. It is found that there are two turning points from ferromagnetic phase to antiferromagnetic phase. One is at 42 K attributed to interface coupling between ferromagnetic Mn3O4 and antiferromagnetic Mn2O3, and the other is at 97 K owing to the interface coupling between ferromagnetic Mn and antiferromagnetic MnO. The samples are shown to have ferromagnetic behaviours at room temperature from hysteresis in the M-H loops, and their ferromagnetism is found to vary with the thickness of Mn nano-film. Moreover, the Mn nano-film has a critical thickness of about 18.5 nm, which makes the coercivity of the multi-film reach a maximum of about 3.965 × 10^-2 T.
基金Supported by the Bidding Project of Qujing Normal University(2011ZB005)
文摘[Objective] The study aimed to extract fulvic acid from brown coal using N-Mn-TiO2 as a catalyst and H2O2 or HNO3 as an oxidizer. [Method] The effects of catalyst N-Mn-TiO2 on the yield and structure of fuMc acid were studied, and the content of functional groups in fulvic acid was analyzed qualitatively and quantitatively. [ Reselt] Two catalysts could improved the yield of fulvic acid, that is, catalyst 1 （N： Mn： 13 = 16： 0.001：1, roasting temperature was 400 ℃） and catalyst 2 （N： Mn： Ti = 16： 0.001：1, roasting temperature was 100 ℃） increased OFA yield by 10.69% and 32.17% and NFA by 8.61% and 7.49% respectively. After the addition of catalysts, the content of total acid radicals in OFA changed little, and carboxyi content increased slightly, but phenolic hydroxyl content decreased. When HNO3 was used as an oxidizer, the content of total acid radicals and phenolic hydroxyl in NFA decreased. In addition, the structure of OFA was different from that of NFA. [Condusion] The research could provide scientific references for the development and application of brown coal in future.
