An Investigation on the Synthesis of Molybdenum Oxide and Its Silica Nanoparticle Composites for Dye Degradation

The molybdenum oxide (MoO(3)) and MoO(3)@SiO(2) nanoparticles were successfully prepared using the chemical bath deposition (CBD) method. The photocatalytic activities of molybdenum oxide (MoO(3)), SiO(2), and MoO(3)@SiO(2) nanoparticles composite have shown a synergistic photocatalytic effect of SiO(2) combined with MoO(3). The first-order degradation rate constants for MoO(3), SiO(2), and MoO(3)@SiO(2) nanocomposite were 10.3 × 10(−3) min(−1), 15.1 × 10(−3) min(−1), and 16.3 × 10(−3) min(−1), respectively. The MoO(3)@SiO(2) composite showed degradation efficiencies in the methylene blue solution close to 100% after 60 min of UV irradiation. The X-ray diffraction (XRD) showed that the MoO(3) powder has a hexagonal crystal structure and the silica is the tridymite type of SiO(2). The crystallite size was about 94 nm, 32 nm, and 125 nm for MoO(3), silica, and MoO(3)@SiO(2), respectively, as calculated by the Scherrer equation. The scanning electron microscopy (SEM) images revealed that the MoO(3) powder consisted of a uniform hexagonal structure; the silica showed a rod-like micro-flake morphology and the MoO(3)@SiO(2) composite had the appearance of coral-like structures.