Evidence of upconversion luminescence contribution to the improved photoactivity of erbium doped TiO2 systems.

Er(3+)-TiO(2) synthesized by a surfactant free hydrothermal method exhibits good photoactivities under sun-like excitation for the degradation of phenol. The presence of Er(3+) does not affect the structural and morphological features of the TiO(2) significantly. The best photocatalytic performance was attained for the samples with 2 wt% of Er. Different photocatalytic runs indicated that the incorporation of the Er(3+) cation would be responsible for the enhanced photocatalytic activity, which participates in different mechanisms under UV and NIR excitation.