Fabrication of GO-TiO2/(Ca,Y)F2:Tm,Yb composites with high-efficiency optical driving photocatalytic activity for degradation of organic dyes and bacteriostasis

Development of photocatalytic materials able to profit from the whole spectrum of sun for efficient organic pollution removal and bacterial elimination is a fascinating strategy in environmental engineering. In current work, GO-TiO2/(Ca,Y)F2:Tm,Yb, a full-spectrum composite photocatalyst, was prepared via hydrothermal processing with TiO2/(Ca,Y)F2:Tm,Yb particles deposited on the surface of graphene oxide (GO). The surface properties of GO-TiO2/(Ca,Y)F2:Tm,Yb were characterized using various characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) surface area analyzer. Besides, ultraviolet–visible (UV–Vis) diffuse reflectance spectroscopy, electron spin resonance (ESR) and other methods were used to systematically explore the photocatalytic mechanism of GO enhancement of TiO2/(Ca,Y)F2:Tm,Yb. In photocatalytic degradation study, the degradation rate of methyl orange (MO) was improved by 40% when GO was added into the TiO2/(Ca,Y)F2:Tm,Yb system. In addition, the presence of GO also improves the antibacterial ability of TiO2/(Ca,Y)F2:Tm,Yb against Escherichia coli and Staphylococcus aureus. All results reveal high efficacy of GO-TiO2/(Ca,Y)F2:Tm,Yb under full spectrum light irradiation, in which (Ca,Y)F2:Tm,Yb and TiO2 can improve its utilization of full spectrum sunlight, and GO can enhance adsorption ability of dye and electron–hole pair differentiation ability of TiO2/(Ca,Y)F2:Tm,Yb.