Photoluminescence and photocatalytic activity of flowerlike hierarchical TiO2:Sm3+ microspheres

Flowerlike hierarchical TiO2:Sm3+ microspheres were successfully prepared via a solvothermal method. The results of the X-ray diffraction measurements revealed that the TiO2:Sm3+ microspheres were anatase phase. The crystalline size of microspheres decreased with increasing Sm3+ concentrations. Each TiO2:Sm3+ microsphere consists of several dozen nanopetals, which are composed of several aggregated nanothorns. Under 290, 360, 362, and 368 nm excitation, the 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, and 4G5/2 → 6H9/2 transitions were observed. The luminescence intensity increased with increasing Sm3+ concentration, up to about 1.5 mol%, and then decreased abruptly. The peak positions and the shape of emissions were independent of Sm3+ concentrations. In addition to the aforementioned photoluminescence properties, TiO2:Sm3+ microspheres can possess superior photocatalytic activity for the degradation of RhB. In addition, the BET surface areas increased with increasing Sm3+ concentrations, which should be benefit for RhB adsorption.