Effective Degradation of Aqueous Nitrobenzene Using the SrFeO_3−δ Photocatalyst under UV Illumination and Its Kinetics and Mechanistic Studies

Abstract

In this article, the SrFeO 3−δ photocatalyst was synthesized by a solution combustion method and applied for the photocatalytic degradation of aqueous nitrobenzene in the presence and absence of H 2 O 2 . The SrFeO 3−δ photocatalyst was characterized by XRD, FT-IR, FE-SEM, TEM, TG-DTG, XPS, and UV–visible spectroscopy. The band gap energy of SrFeO 3−δ was found to be 3.75 eV which lies in the UV region. The XPS results indicate that the oxidation state of Sr and Fe in SrFeO 3−δ was 2+ and 3+, respectively, and the surface atomic ratio of Sr and Fe is 0.995. The photocatalytic activity reveals that the degradation of nitrobenzene over the SrFeO 3−δ catalyst itself (UV/SFO) is superior compared to SrFeO 3−δ in the presence of H 2 O 2 (UV/SFO/H 2 O 2 ) with a degradation efficiency of 99–96%. The degradation of nitrobenzene obeys first-order kinetics in both UV/SFO and UV/SFO/H 2 O 2 processes. The decrease in degradation efficiency with UV/SFO/H 2 O 2 was attributed due to the formation of strontium carbonate on the photocatalyst surface.