Synthesis, characterization and photocatalytic activity of Mn2O3/Al2O3/Fe2O3 nanocomposite for degradation of malachite green

A Mn2O3/Al2O3/Fe2O3 nanocomposite photocatalyst was prepared by a co-precipitation method. Flame atomic absorption spectroscopy (FAAS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and UV–Vis diffuse absorption spectroscopy (UV–Vis DAS) were employed to study elemental composition, functional group identification, structure, morphology, and band gap of the as-synthesized nanocomposite. The highest photodegradation efficiency was recorded for the sample containing the 10/10/80 percentages composition of Mn2O3/Al2O3/Fe2O3, respectively. The average crystallite size calculated from XRD for this sample was 40 nm. UV-Vis diffuse absorbance of the sample showed strong absorption in visible region at 550 nm, which is comparable to Fe2O3 which has absorption at 563.6 nm. This confirmed that coupling with alumina and manganese oxide did not contribute to the band gap narrowing but to delay the electron-hole recombination as witnessed by the highest photodegradation efficiency.