Preparation of Yb, N, and F doped Er3+:Y3Al5O12/TiO2 composite films for visible-light photocatalytic degradation of organic dyes

Abstract

Several up-conversion luminescent materials (Er3+:Y3Al5O12, Yb doped Er3+:Y3Al5O12, Yb and N co-doped Er3+:Y3Al5O12, Yb and F co-doped Er3+:Y3Al5O12, and Yb, N, and F co-doped Er3+:Y3Al5O12) were synthesized using sol–gel method. The corresponding TiO2 composite films (Er3+:Y3Al5O12/TiO2, Yb doped Er3+:Y3Al5O12/TiO2, Yb and N co-doped Er3+:Y3Al5O12/TiO2, Yb and F co-doped Er3+:Y3Al5O12/TiO2, and Yb, N, and F co-doped Er3+:Y3Al5O12/TiO2) were prepared by sol–gel dip-coating method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). The UV–Vis absorption and PL spectra of Er3+:Y3Al5O12 were also determined. The visible-light photocatalytic activity of the synthesized materials was evaluated in the degradation of Azo Fuchsine (AF) dye in aqueous solution. The concentration of the dye was monitored by UV–Vis spectroscopy. Some key factors, such as layer number, heat-treatment temperature and time on the photocatalytic activity of Yb, N, and F co-doped Er3+:Y3Al5O12/TiO2 composite films were studied. The doping of Yb, N, and F into Er3+:Y3Al5O12/TiO2 significantly enhanced the visible-light photocatalytic activity of Er3+:Y3Al5O12/TiO2 composite film in the degradation of organic dyes. The experiments also indicated that the Yb, N, and F co-doped Er3+:Y3Al5O12/TiO2 composite film has a good visible-light photocatalytic activity to degrade other organic dyes under visible-light irradiation.