Optical, dielectric and photocatalytic properties of Ag-doped Sr1_xAgxFe12O19 and CV dye degradation under visible light irradiation

In the present study, a series of silver-doped strontium hexaferrite (Sr1_xAgxFe12O19) were fabricated by microemulsion route. The influence of dopant (Ag) on the structural, dielectric, optical and photocatalytic properties was analyzed, which were characterized by XRD, Raman, SEM, FTIR and UV-visible techniques along with photoluminescence and dielectric measurements. The XRD and Raman studies display the M-type hexagonal ferrite formation with a P63/mmc space group with an average crystallite size of 25-32 nm. For Ag-doped SrFe12O19, the UV-visible absorption coefficient showed a substantial red shift, leading to the reduction of the bandgap to 3.2-2.6 eV. The PL spectra reveal that highly doped materials displayed lower re-combination and enhanced charge-separation (e --h+). With dopant concentration, the dielectric loss decreased, while AC con-ductivity and dielectric constant increased. The photocatalytic activity was studied by degradation of the crystal violet (CV) dye under visible light irradiation and up to 86% dye degradation was achieved for Sr1_xAgxFe12O19 versus SrFe12O19 (54%) in 120 min. Moreover, the stability was confirmed by consecutive cycles and doped material showed higher stability and reusability versus undoped. The effect of different scavengers was also studied to evaluate the dye degradation mechanism. In view of enhanced optical and catalytic properties, the Sr1_xAgxFe12O19 could be employed for the remediation of dyes in textile effluents under solar light irradiation, which will make the process economical versus UV light-based photocatalytic processes.