Nanosized metal （Pt or Pd）-decorated TiO2 nanofibers （NFs） were synthesized by a wet impregnation method. CdSe quantum dots （QDs） were then anchored onto the metal-decorated TiO2 NFs. The photocatalytic performa...Nanosized metal （Pt or Pd）-decorated TiO2 nanofibers （NFs） were synthesized by a wet impregnation method. CdSe quantum dots （QDs） were then anchored onto the metal-decorated TiO2 NFs. The photocatalytic performance of these catalysts was tested for activation and reduction of CO2 under UV-B light. Gas chromatographic analysis indicated the formation of methanol, formic acid, and methyl formate as the primary products. In the absence of CdSe QDs, Pd-decorated TiO2 NFs were found to exhibit enhanced performance compared to Pt-decorated TiO2 NFs for methanol production. However, in the presence of CdSe, Pt-decorated TiO2 NFs exhibited higher selectivity for methanol, typically producing -90 ppmg^-1.h^-1 methanol. The CO2 photoreduction mechanism is proposed to take place via a hydrogenation pathway from first principles calculations, which complement the experimental observations.展开更多
This paper describes a detailed analysis of the dependence of Raman scattering intensity on the polarization of the incident and inelastically scattered light in PbSc_(0.5)Nb_(0.5)O_(3)(PSN)single crystals and epitaxi...This paper describes a detailed analysis of the dependence of Raman scattering intensity on the polarization of the incident and inelastically scattered light in PbSc_(0.5)Nb_(0.5)O_(3)(PSN)single crystals and epitaxially compressed thin films grown on(100)-oriented MgO substrates.It is found that there are significant differences between the properties of the crystals and films,and that these differences can be attributed to the anticipated structural differences between these two forms of the same material.In particular,the scattering characteristics of the oxygen octahedra breathing mode near 810 cm^(-1) indicate a ferroelectric state for the crystals and a relaxor state for the films,which is consistent with the dielectric behaviors of these materials.展开更多
文摘Nanosized metal （Pt or Pd）-decorated TiO2 nanofibers （NFs） were synthesized by a wet impregnation method. CdSe quantum dots （QDs） were then anchored onto the metal-decorated TiO2 NFs. The photocatalytic performance of these catalysts was tested for activation and reduction of CO2 under UV-B light. Gas chromatographic analysis indicated the formation of methanol, formic acid, and methyl formate as the primary products. In the absence of CdSe QDs, Pd-decorated TiO2 NFs were found to exhibit enhanced performance compared to Pt-decorated TiO2 NFs for methanol production. However, in the presence of CdSe, Pt-decorated TiO2 NFs exhibited higher selectivity for methanol, typically producing -90 ppmg^-1.h^-1 methanol. The CO2 photoreduction mechanism is proposed to take place via a hydrogenation pathway from first principles calculations, which complement the experimental observations.
基金supported by the Czech Science Foundation(Projects CSF 15-04121S and 15-15123S)the United Stated Office of Naval Research(Grant No.N00014-12-1-1045)the Natural Science&Engineering Research Council of Canada(NSERC).
文摘This paper describes a detailed analysis of the dependence of Raman scattering intensity on the polarization of the incident and inelastically scattered light in PbSc_(0.5)Nb_(0.5)O_(3)(PSN)single crystals and epitaxially compressed thin films grown on(100)-oriented MgO substrates.It is found that there are significant differences between the properties of the crystals and films,and that these differences can be attributed to the anticipated structural differences between these two forms of the same material.In particular,the scattering characteristics of the oxygen octahedra breathing mode near 810 cm^(-1) indicate a ferroelectric state for the crystals and a relaxor state for the films,which is consistent with the dielectric behaviors of these materials.
