Microwave-assisted synthesis of nanostructured perovskite-type oxide with efficient photocatalytic activity against organic reactants in gaseous and aqueous phases

Microwave-assisted synthesis as a straightforward, efficient and time-saving approach is used for the synthesis of LaFeO3 nanoparticles. The obtained perovskite showed a narrow band gap energy (2.12 eV), high crystallinity, great oxygen adsorption/ desorption ability and mesoporous structure. In order to assess the photocatalytic activity, benzene and reactive black 5 (RB5) dye are used as gaseous and aqueous reactants, respectively. Under visible light irradiation, almost 85% benzene and 96% RB5 degradation are obtained over the perovskite. The reactions are monitored for 60 min using Gas Chromatography (FID&TCD) and UV-VIS spectrophotometer. The dye degradation process is studied thoroughly, from the mechanistic point of view. Surface charge density of LaFeO3 is measured at different dye concentration to identify the electrical nature of the surface whether it is positive or negative. Moreover, a series of reactions are conducted to monitor the effect of scavengers on the rate of the photocatalytic dye degradation and decipher which active species (hydroxyl and superoxide radicals or the holes) have dominated the dye oxidation reaction. In the present study, hydroxyl radicals are found as the main active species in the photocatalytic degradation reaction.