Enhanced photocatalytic activity of layered MoO₃ in removal of organic pollutant under visible light

One of the fundamental problems throughout the world is the environment pollution and out of which water pollution is very acute one of them. The aim of the work is to synthesize visible light driven photocatalysts to decompose organic pollutants dissolved in wastewater through the conversion of solar energy. Molybdenum trioxide is one of the most interesting transition metal oxides, which is being used as a promising photocatalyst due to its multiple valance states, high thermal and chemical stability. MoO₃ crystallizes with three basic polytypes: orthorhombic MoO₃ (α), monoclinic MoO₃ (β) and hexagonal MoO₃ (h), among which α-phase is most interesting because of its layered crystal structure. Various synthesis procedures have been made to prepare α-MoO₃ such as hydrothermal/solvothermal method, sol-gel method, self-propagating combustion, flash evaporation, vapour phase deposition, flame synthesis technique and so on. Applications of MoO₃ have been widely spread in many fields such as wastewater treatment, capacitors, heterojunction photovoltaic, cathode materials for lithium and sodium ion batteries and electrolytic materials. The present study investigates the structure, morphologies, optical and photocatalytic properties of α-MoO₃ sintered at different elevated temperatures in open air. The photocatalytic performance of the prepared samples has been investigated with organic pollutant, Rhodamine B dye molecules and under 200W tungsten filament lamp as a source of visible light. The photocatalytic activity of the sample is found to enhance significantly with increasing sintering the temperature. (author)