TiO₂- and BaTiO₃-Assisted Photocatalytic Degradation of Selected Chloroorganic Compounds in Aqueous Medium: Correlation of Reactivity/Orientation Effects of Substituent Groups of the Pollutant Molecule on the Degradation Rate

Abstract

Investigation of the photocatalytic activity of BaTiO(3), a perovskite wideband gap semiconductor has been done in comparison with a widely used photocatalyst TiO(2) for the degradation of 4-chlorophenol (4-CP), 4-chloroaniline (4-CA), 3,4-dichloronitrobenzene (3,4-DCNB), and 2,4,5-trichlorophenol (2,4,5-TCP). BaTiO(3)/TiO(2) nanoparticles were prepared by gel-to-crystalline conversion method. BaTiO(3) has exhibited better catalytic efficiency and process efficiency compared with TiO(2) in most of the cases. The present research focuses mainly on two aspects: first the photocatalytic activity of BaTiO(3), as there are very few reports in the literature, and second the reactivity/orientation effects of substituent groups of the pollutant molecules on the degradation rate. The above chloroorganic compounds have at least one chlorine substituent in common, along with other functional groups such as -OH, -NH(2), and -NO(2). Furthermore, the effect of electron acceptors and pH on the rate of degradation is presented. The reactions follow first-order kinetics. The degradation reaction was followed by UV-vis, IR, and GC-MS spectroscopic techniques. On the basis of the identification of the intermediates, a probable degradation reaction mechanism has been proposed for each compound.

Synergistic effect of Ag deposition and nitrogen doping in TiO2 for the degradation of phenol under solar irradiation in presence of electron acceptor

“…Therefore, Ag loading can effectively decrease the rate of charge carrier recombination and the photocatalytic activity is better than the nitrogen doped TiO 2 . The presence of electron acceptors can accelerate the electron transfer and inhibit the fast electron-hole recombination in various catalysts like TiO 2 /BaTiO 3 /TiO 2−x N x as reported in our previous work [21,42]. The experiment with electron acceptors was repeated for the present catalyst Ag-TiO 2−x N x and results shows that the presence of electron acceptor enhances the rate.…”

Photocatalytic activity of CaTaO 2 N nanocrystals obtained from a hydrothermally synthesized oxide precursor

“…On the other hand, photocatalytic wastewater treatment is another highly interesting use for oxynitrides [20][21][22][23][24]. Possible applications are treatment of hospital sewerage containing pharmaceutical substances as well as processing of drinking water.…”

Enhanced photocatalytic activity of BaTiO3@g-C3N4 for the degradation of methyl orange under simulated sunlight irradiation

“…Titanium dioxide and various titanium-based oxide semiconductors are famously known to be an important class of photocatalysts and have been the focus of research interest. Among them, BaTiO 3 , a well-known perovskite-type multimetallic oxide with a bandgap energy of $3.2 eV, has been shown to exhibit a photocatalytic activity toward degradation of methyl red, methyl orange, methylene blue, herbicide pendimethalin and safranin T [5][6][7][8]. Moreover, the conduction-and valence-band edges of BaTiO 3 straddle the redox potentials of H + /H 2 and O 2 /H 2 O [9], thus making it have the ability to photocatalytically split water into H 2 and O 2 .…”