Kinetics of the photocatalytic degradation of methylene blue under natural sunlight irradiation using nanocatalysts Ce3+ and Mg2+ co-doped CaFeO3−δ

Nanoparticles of pure and co-doped according to the formula Ca1−yCeyFe1−xMgxO3−δ (x = y = 0.0, y = 0.1; x = 0.0, 0.1, 0.2) have been successfully synthesized through a wet chemical sol–gel method using citric acid as a chelating agent. So, the prepared materials after calcination at 800 °C for 6 h were examined for structural, optical, and photocatalytic properties using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (IRTF), and ultraviolet–visible spectrophotometer (UV–Vis). The X-ray diffraction measurements of all the compositions confirm the formation of a single-phase orthorhombic perovskite-related structure, with a Pcmn space group without any other heterogeneity or structural transition. The crystallite size is found to decrease with increasing Mg2+ doping in Ca0.9Ce0.1Fe1−xMgxO3−δ. The results of the FTIR analysis confirmed the presence of the typical band characteristics of metal oxygen bonds, which are features of FeO6 octaedra in the oxide perovskite materials. UV–Vis optical spectra revealed that the band gap of pure CaFeO3−δ observed in the visible range was tuned by doping Ce3+ and Mg2+, which has improved the photodegradation efficiency and kinetic degradation rates of methylene blue under sunlight irradiation. The possible mechanism of the photocatalytic activity is also proposed in this contribution.