By electrodeposition in organic system,NiO films with reversible electrochromic property were fabricated.Fluorine-doped tin oxide glass slices were used as substrates,i.e.cathodes.Cyclic voltammetry and ultraviolet-vi...By electrodeposition in organic system,NiO films with reversible electrochromic property were fabricated.Fluorine-doped tin oxide glass slices were used as substrates,i.e.cathodes.Cyclic voltammetry and ultraviolet-visible transmission spectroscopy were adopted to study the electrochromic properties of the films.High resolution transmission electron microscopy(HRTEM) was employed to analyze the composition and structure of the films.It is found that the films are composed of fine NiO crystal grains of a few nanometers in diameter,endowing them with large visible light transmittance variation,rapid switch rate(i.e.rapid response time) between the bleached and colored states.Their cycling durability reached 6000 cycles.展开更多
Perylene tetracarboxylic diimide (PTCDI),widely used in organic photovoltaic devices,is an n-type semiconductor with strong absorption in the visible-light spectrum.There has been almost no study of the PTCDI-sensitiz...Perylene tetracarboxylic diimide (PTCDI),widely used in organic photovoltaic devices,is an n-type semiconductor with strong absorption in the visible-light spectrum.There has been almost no study of the PTCDI-sensitized TiO2 composite used to photocatalytically degrade pollutants.In this study,PTCDIand copper phthalocyanine tetrasulfonic acid (CuPcTs)-sensitized TiO2 composites were prepared using a hydrothermal method.The morphologies and structures of the two composites were characterized by X-ray diffraction,transmission electron microscopy,ultraviolet-visible spectroscopy,and fluorescence spectroscopy.The visible-light photocatalytic activities of the composites were evaluated using the degradation of rhodamine B as a model reaction.Results showed that dye-sensitized TiO2 samples had a wider absorption spectrum range and higher visiblelight photocatalytic activity compared to TiO2 samples.The double dye-sensitized (or co-sensitized) TiO2 composite with efficient electron collection exhibited higher photocatalytic activity than did the single dye-sensitized TiO2 composite.The electron transfer processes of single and double dye-sensitized TiO2 composites were illustrated according to band theory.展开更多
A water-in-oil microemulsion made up of a cyclohexane/n-hexyl alcohol/Polyethylene glycol tertoctylphenyl/aqueous solution including Bi3+ and VO+3 ions yields the spherical BiVO4 precursors with the size from 5 to 300...A water-in-oil microemulsion made up of a cyclohexane/n-hexyl alcohol/Polyethylene glycol tertoctylphenyl/aqueous solution including Bi3+ and VO+3 ions yields the spherical BiVO4 precursors with the size from 5 to 300 nm. Well-crystallized monoclinic scheelite BiVO4 particles with nanometer or micrometer size are fabricated in control by heating microemulsion precursors under various temperatures. The corresponding nucleation and growth process of as-prepared samples has also been investigated via TEM,which demonstrates the detailed morphological evolution of nuclei inside the precursors. As-prepared BiVO4 photocatalysts exhibit enhanced photocatalytic activity under visible-light irradiation in comparison with the bulk BiVO4 prepared by solid-state reaction. The highest RB degrading efficiency of 98% in 180 min under visible-light irradiation is observed for the sample calcined at 600 °C.展开更多
Nitrogen-doped HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide （TBAOH） to obtain HTiNbO5 nanosheets and then heating the nanosheets with ure...Nitrogen-doped HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide （TBAOH） to obtain HTiNbO5 nanosheets and then heating the nanosheets with urea. The resulting samples were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, energy-dispersive X-ray （EDX）, X-ray photoelectron spectroscopy （XPS）, UV-vis spectroscopy and N2 adsorption-desorption measurements. It was found that N-doping resulted in a much higher thermostability of the layered structure, intrinsic bandgap narrowing and a visible light response. The doped nitrogen atoms were mainly located in the interstitial sites of TiNbOs- lamellae and chemically bound to hydrogen ions. Compared with N-doped HTiNbOs, N-doped HTiNbO5 nanosheets had a much larger specific surface area and richer mesoporosity due to fee rather loose and irregular arrangement of fitanoniobate nanosheets. Both N-doped layered HTiNbOs and HTiNbO5 nanosheets showed a very high visible-light photocatalytic activity for the degradation of rhodamine B （RhB） aqueous solution. Moreover, due to the considerably larger surface area, richer mesoporosity and stronger acidity, N-doped HTiNbO5 nanosheets had an even higher activity than N-doped HTiNbOs, although the latter had a stronger absorption in the visible region. The dye molecules were mainly degraded to aliphatic organic compounds and partially mineralized to CO2 and/or CO, rather than being simply decolorized. The effect of photosensitization was insignificant and RhB was degraded mainly via the typical photocatalytic reaction routes. Two different reaction routes for the photodegradation of RhB under visible light irradiation over N-doped HTiNbO5 nanosheets have been proposed. The present method can be extended to a large number of layered metal oxides that have the characteristics of intercalation and exfoliation, thus providing new opportunities for the fabrication of highly effective and potentially practical visible-light photocatalysts.展开更多
基金sponsored by the Natural Science Foundation of Shandong Province of China (Grant No. ZR2010EM027)the Applied and Basic Research Project (11-2-4-1-(2)-jch) of Qingdao Municipal Science Technology Commission of China
文摘By electrodeposition in organic system,NiO films with reversible electrochromic property were fabricated.Fluorine-doped tin oxide glass slices were used as substrates,i.e.cathodes.Cyclic voltammetry and ultraviolet-visible transmission spectroscopy were adopted to study the electrochromic properties of the films.High resolution transmission electron microscopy(HRTEM) was employed to analyze the composition and structure of the films.It is found that the films are composed of fine NiO crystal grains of a few nanometers in diameter,endowing them with large visible light transmittance variation,rapid switch rate(i.e.rapid response time) between the bleached and colored states.Their cycling durability reached 6000 cycles.
基金supported by the National Natural Science Foundation of China (20407002)National Basic Research Program of China (2002CB410802)Special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control
文摘Perylene tetracarboxylic diimide (PTCDI),widely used in organic photovoltaic devices,is an n-type semiconductor with strong absorption in the visible-light spectrum.There has been almost no study of the PTCDI-sensitized TiO2 composite used to photocatalytically degrade pollutants.In this study,PTCDIand copper phthalocyanine tetrasulfonic acid (CuPcTs)-sensitized TiO2 composites were prepared using a hydrothermal method.The morphologies and structures of the two composites were characterized by X-ray diffraction,transmission electron microscopy,ultraviolet-visible spectroscopy,and fluorescence spectroscopy.The visible-light photocatalytic activities of the composites were evaluated using the degradation of rhodamine B as a model reaction.Results showed that dye-sensitized TiO2 samples had a wider absorption spectrum range and higher visiblelight photocatalytic activity compared to TiO2 samples.The double dye-sensitized (or co-sensitized) TiO2 composite with efficient electron collection exhibited higher photocatalytic activity than did the single dye-sensitized TiO2 composite.The electron transfer processes of single and double dye-sensitized TiO2 composites were illustrated according to band theory.
基金supported by the Foundation for Outstanding Young Scientist of Shandong Province (BS2010CL049)the Program for New Cen-tury Excellent Talents in University (NCET-08-0511)
文摘A water-in-oil microemulsion made up of a cyclohexane/n-hexyl alcohol/Polyethylene glycol tertoctylphenyl/aqueous solution including Bi3+ and VO+3 ions yields the spherical BiVO4 precursors with the size from 5 to 300 nm. Well-crystallized monoclinic scheelite BiVO4 particles with nanometer or micrometer size are fabricated in control by heating microemulsion precursors under various temperatures. The corresponding nucleation and growth process of as-prepared samples has also been investigated via TEM,which demonstrates the detailed morphological evolution of nuclei inside the precursors. As-prepared BiVO4 photocatalysts exhibit enhanced photocatalytic activity under visible-light irradiation in comparison with the bulk BiVO4 prepared by solid-state reaction. The highest RB degrading efficiency of 98% in 180 min under visible-light irradiation is observed for the sample calcined at 600 °C.
基金Acknowledgements The authors greatly appreciate the financial support of the National Natural Science Foundation of China （Grant Nos. 21073084 and 20773065）, the National Basic Research Program （973 Project） （Grant No. 2007CB936302） and the Modern Analysis Center of Nanjing University.
文摘Nitrogen-doped HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide （TBAOH） to obtain HTiNbO5 nanosheets and then heating the nanosheets with urea. The resulting samples were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, energy-dispersive X-ray （EDX）, X-ray photoelectron spectroscopy （XPS）, UV-vis spectroscopy and N2 adsorption-desorption measurements. It was found that N-doping resulted in a much higher thermostability of the layered structure, intrinsic bandgap narrowing and a visible light response. The doped nitrogen atoms were mainly located in the interstitial sites of TiNbOs- lamellae and chemically bound to hydrogen ions. Compared with N-doped HTiNbOs, N-doped HTiNbO5 nanosheets had a much larger specific surface area and richer mesoporosity due to fee rather loose and irregular arrangement of fitanoniobate nanosheets. Both N-doped layered HTiNbOs and HTiNbO5 nanosheets showed a very high visible-light photocatalytic activity for the degradation of rhodamine B （RhB） aqueous solution. Moreover, due to the considerably larger surface area, richer mesoporosity and stronger acidity, N-doped HTiNbO5 nanosheets had an even higher activity than N-doped HTiNbOs, although the latter had a stronger absorption in the visible region. The dye molecules were mainly degraded to aliphatic organic compounds and partially mineralized to CO2 and/or CO, rather than being simply decolorized. The effect of photosensitization was insignificant and RhB was degraded mainly via the typical photocatalytic reaction routes. Two different reaction routes for the photodegradation of RhB under visible light irradiation over N-doped HTiNbO5 nanosheets have been proposed. The present method can be extended to a large number of layered metal oxides that have the characteristics of intercalation and exfoliation, thus providing new opportunities for the fabrication of highly effective and potentially practical visible-light photocatalysts.
