Dong Zhang,Xuanxuan Ma,Qi Zhang,Yanru Xie,Qiang Shi,Qiangru Wang,Wenjun Wang
Zn x Al 2 O 4 :Cr 3+ (0.8 ≤ x ≤ 4) phosphors with spinel structure were prepared by using sol-gel method. The structure, morphology and photoluminescence properties were analyzed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR) and photoluminescence (PL). The spinel structure of ZnAl 2 O 4 was formed for all samples, and hexagonal structure of ZnO appeared in the powders with x ≥ 1.1. The results of XRD, SEM and TEM showed that the crystallinity of Zn x Al 2 O 4 :Cr 3+ phosphors was improved with increasing the value of x . The PL spectra showed a series of sharp emission peaks ranging from 650 nm to 730 nm assigned to spin-forbidden 2 E g → 4 A 2 g transition of Cr 3+ ions in spinel lattices. The most intense emission was observed in Zn 1.2 Al 2 O 4 :Cr 3+ powders, and the results of EPR showed that this enhancement resulted from the best dispersity of Cr 3+ ions in Zn x Al 2 O 4 lattices.
In recent years, the excessive use of antibiotics has become a serious problem for human health. BiVO 4 regarded as one of the most promising visible-light-driven photocatalysts was used to degrade the antibiotics. In this paper, we fabricated Bi/BiVO 4 plasmonic photocatalysts which enhanced the photocatalytic activity of BiVO 4 for degradation of tetracycline (TC) antibiotic. The Bi/BiVO 4 photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy . In addition, the photocatalytic experiment results show that the 0.04-Bi/BiVO 4 sample has the best photocatalytic activity for 2 times than the pure BiVO 4 photocatalyst. The cycle experiments, after four repetitions of the experiments, showed the sample still maintained a high photocatalytic activity. Finally, the photocatalytic reaction mechanism was also studied by free radical capture experiments and electron paramagnetic resonance spectroscopy .