Solution-combustion synthesis of anion (iodine) doped TiO2 nanoparticles for photocatalytic degradation of Direct Blue 199 dye and regeneration of used photocatalyst

Abstract

Citric acid assisted undoped and I doped TiO2, Ti1-xIxO2 (x = 0.00, 0.01, 0.03, 0.05, 0.07 and 0.09) have been synthesized successfully by solution-combustion technique. The characterization of synthesized photocatalysts was done using different characterization techniques such as XRD, DRS, FT-IR, XPS, TEM, and EDX. The XRD diffraction patterns revealed that synthesized photocatalysts have only the anatase phase of TiO2. The DRS analysis indicates that with increasing the doping concentration of I in TiO2, a continuous shifting in absorbance was observed towards the visible light region. The FT-IR spectra determine the various functional groups which are present in the synthesized photocatalysts. The XPS spectra confirm the existence of all expected elements (Ti, O, and I) in the synthesized photocatalysts and determine their binding energies and chemical state. The shape and crystallite size of undoped and I doped TiO2 (Ti0.97I0.03O2) photocatalysts were determined by TEM analysis. The chemical composition of the synthesized photocatalysts was examined by EDX analysis. Simulated solutions of dye (Direct Blue 199) of different concentrations were photodegraded by the synthesized photocatalysts to determine photocatalytic activities of the synthesized photocatalysts in the UV photochemical reactor (UV-PCR) and open pan reactor (OPR). The Ti0.97I0.03O2 photocatalyst shows the highest photocatalytic activity among all the synthesized undoped, and I doped TiO2 photocatalysts. The synthesized photocatalyst (Ti0.97I0.03O2) was also found better than commercially available Aeroxide P-25 photocatalyst in respect of the dye photodegradation. The used I doped TiO2 photocatalyst (Ti0.97I0.03O2) was regenerated five times and investigated its photocatalytic activity again. © 2020