Synthesis and characterisation of visible light-responsive Fe-doped BiOCl NPs and their application for the remediation of textile dye by LED irradiation

In the present research work, Fe-doped bismuth oxychloride (Fe-doped BiOCl) photocatalyst is synthesised through the precipitation technique, and the mineralisation of textile dye is investigated in the presence of light-emitting diode (LEDs) irradiation (400-700 nm). The prepared photocatalysts were characterised through various spectroscopic techniques for the detailed morphological, elemental and surface properties. The UV-vis absorbance maxima of Fe-doped BiOCl by UV-Vis was near 358 nm, while the band gap was 4.8 eV which is comparatively higher than the average value. Fourier transform infrared spectra showed typical bands of Fe doped BiOCl at 506 cm-1, 1601, 2337 and at 3565.0 cm-1. From the X-ray diffraction (XRD) pattern, the crystalline nature of the Fe-doped nanocomposite was confirmed whose calculated crystallite size was 41.12 nm. The major and sharp two theta peaks of XRD were at 11.95 degrees, 24.07 degrees, 25.81 degrees, 32.46 degrees, 33.39 degrees, 36.47 degrees. The microscopic technique showed that the size of the nanocomposite was 200-400 nm which was in the form of small nanosheets. The energy dispersive X-ray spectroscopy (EDS) showed peaks for Bi, O, Cl and Fe 36.91%, 26.48%, 36.37% and 0.24%, respectively, indicating the formation of the nanocomposite. The BET surface area of the Fe-doped BiOCl photocatalyst was 10.224 m2/g, while the pore volume was 0.065 cc/g. Further, the potential of the developed photocatalytic nanocomposite was evaluated for the photocatalytic degradation of the ethyl violet dye from the aqueous solutions. Various optimisation parameters have been discussed, and it has been found that 89% of the dye was degraded in 125 min with a 5.11 x 10-4 s-1 rate constant. The photocatalyst had shown excellent reusability and stability during the degradation of ethyl violet. The photocatalytic activity of Fe-doped BiOCl was compared with other photocatalysts and current literature and exhibited enhanced efficiency.