Evidence of upconversion luminescence contribution to the improved photoactivity of erbium doped TiO 2 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.