Optimized enhanced photodegradation activity of sintered molybdenum oxide: A morphological hierarchy in wastewater treatment

Abstract Morphological transformations of the MoO2 sample sintered at 550°C, 650°C, 750°C and 850°C in the open air are revealed by the respective FESEM images. Microstructure characterization of these sintered samples has been accomplished by analyzing the XRD patterns employing Rietveld refinement technique, TEM images and FTIR spectra. Formation of a single orthorhombic α-MoO3 phase with layered microbar morphology has been revealed after sintering at 650°C and with increasing sintering temperature existence of another isostructural MoO2.5(OH)0.5 phase is noticed with a significant increase in the length of these microbars. Optical bandgaps of the sintered semiconducting samples have been determined using respective UV–vis absorption spectra. The degradation of the model organic pollutant RhB under visible light in aqueous solution has been investigated by the sample sintered at different temperatures and compared with the unsintered sample. Significantly degradation of RhB (∼91 %) under visible light with the sample sintered at 650°C for 2h.