Photocatalytic activity and luminescent properties of Y, Eu, Tb, Sm and Er-doped ZrO_{2 nanoparticles obtained by hydrothermal method

Nanoparticles in the ZrO2-Me2O3 system (where Me = Y, Eu, Tb, Sm, Er) with different phase composition (m-ZrO2, t-ZrO2, c-ZrO2), size (5÷25 nm) and morphology (spheres, hollow spheres, rods and star structure) were obtained by hydrothermal synthesis. Photocatalytic activity was measured for the reaction of photoinduced hydrogen evolution from aqueous isopropyl alcohol. Dependence of photocatalytic activity on specific surface area and crystallite size of the particles was shown. Introduction of lanthanide ions in the ZrO2 structure did not lead to the change in the band gap energy and had no significant effect on the amount of hydrogen generated. Luminescence bands of the ZrO2-based solid solution nanoparticles with lanthanide ions (LnIII), which are located in different regions of the visible spectrum with distinctive LnIII for quasi-monochromatic lines (Tb - green area, Eu, Sm - orange-red), were shown by fluorescent spectroscopy. The maxima in the photon-absorbing region of the ZrO2 matrix for excitation spectra of these systems were observed. It may be owing to the states of charge transfer from the O atom to LnIII.