PHOTOCATALYTIC DEGRADATION OF AQUEOUS METHYL ORANGE USING NANOTITANIA LOADED Mo-MCM-41

Abstract

Nanocrystalline titanium dioxide, TiO2 , is a well studied and commonly used material for photocatalytic applications. However, the control of particle size, monodispersity, large catalytic surface for sufficient adsorption of organic pollutants, recovery and recycle of TiO2 nanoparticles are challenging tasks. Hence in this work, titania has been introduced into the nanopores (2–10 nm size) of MCM-41 to produce stable nanoparticles of uniform size and shape. Further, the photocatalytic efficiency can be improved by lengthening the life time of the excited electrons/holes during photoreaction. This could be achieved by incorporating molybdenum in to the MCM-41 silica matrix in addition to titania loading. In the present study, the synthesis and the photocatlaytic efficiency of a new photocatalyst TiO2@Mo -MCM-41 (25 wt.% TiO2 loaded Mo incorporated MCM-41) are reported. Mo -MCM-41, with different ratios of Si to Mo ( Si/Mo = 25,50,75), is synthesized by hydrothermal method and loaded with 25 wt.% TiO2 using sol–gel method. The photocatalytic activity of the prepared samples was evaluated using methyl orange as a model organic compound. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and nitrogen adsorption–desorption isotherm (BET analysis) measurements were used to investigate the effects of the incorporated elements in the structure of MCM-41. It was found that the photodegradation ability of 25% TiO2 loaded Mo -MCM-41 was highly related to the amount of Mo atoms present in the sample with the optimum atomic ratio of Si to Mo being 50.