Silver and yttrium-doped bismuth vanadate for photoluminescent activity and boosted visible light-induced photodegradation

摘要

Silver and ytterbium-doped bismuth vanadate (Ag_xYb_yBi_(z_xy)VO_4) composites have been synthesized via solid state-reaction in one-step at 950 °C for 6 h in the open air atmosphere. The effect of dopants concentration on the morphology, the optical property and the dye degradation efficiency was studied by X-ray Diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy, thermogravi-metric analysis (TGA), scanning electron microscope (SEM), photoluminescence (PL) spectroscopy and Fourier transform infrared (FTIR) and UV-Visible spectroscopy. The scanning electron microscopic analysis has revealed the presence of most irregular-shaped particles; however, some definite grain-like particles have also been seen. EDX analysis disclosed the presence of V, Bi, Ag, Yb and O in the doped materials. TGA has described the stability of doped materials at the ordinary temperature. Fourier transform infrared results of Ag_xYb_yBi_(z_xy)VO_4 composites have indicated the formation of vanadium pentaoxide based materials and the presence of V-O bond. The calculated optical band gaps of V_2O_5 and composites have been recorded as 2.25, 1.56 and 1.75 eV, respectively. The Nyquist plot has demonstrated nearly straight lines for V_2O_5 and composites which is attributed to the higher charge transfer potential. The photoluminescence spectra of the doped materials have revealed the presence of spectral bands in the red and red to infrared regions which could be used in the optical devices. The degradation efficiency of crystal violet (CV) dye was explored under the solar-light irradiation. A remarkable dye degradation efficiency of 94.57% has been recorded for 7 mg/L of the dye solution within 120 min. Besides, the proposed dye degradation mechanism and reusability experiment was also discussed in detail. The photoluminescent study of the materials exhibited emission bands at 1088 and 1045 nm are recorded which could be used in optical devices.