Synthesis, Characterization and Photocatalytic Activity of Transition Metal Vanadates Based Nanocomposites

Abstract

As a result of industrial revolution, a remarkable increase has been observed in the global energy utilization and environmental pollution. Currently, major energy requirements are being fulfilled by non-renewable energy sources. Renewable energy sources are gaining popularity with time, because of being an infinite source of energy, cost effectiveness etc. World is facing severe energy and environmental crisis, and majorly the organic effluents from industrial wastes are damaging environment to an alarming degree. Water pollution, a major type of pollution, is a cause of various potential acute health diseases and potential chronic health diseases. Contaminants must be decomposed to smaller levels before disposal, so that they are not harmful to humans and the environment. Various methods used for the removal of toxic organic pollutants include biological, physical and chemical methods. Among the available chemical methods, heterogeneous photocatalytic oxidation is an effective method for the degradation of large number of persistent organic pollutants. Semiconductor based photocatalysts are commonly used materials for the photodegradation of organic pollutants and toxic dyes. Factors that affect the efficiency of a photocatalytic system include nanostructuralization, doping, heterostructure formation, sensitization etc. Here, use of Zn3V2O8/Co3V2O8 and Co3V2O8 /g-C3N4 for photocatalytic dye degradation has been discussed. Co-precipitation method has been used for the synthesis of UV light active Zn3V2O8 and visible light active Co3V2O8 nanoparticles. Thermal decomposition method has been used for the synthesis of g-C3N4. Both Zn3V2O8 and Co3V2O8 have orthorhombic geometry, and the composite shows good photocatalytic efficiency towards the degradation of Congo red which is upto 70%. Photocatalytic activity of nanocomposites of cubic g-C3N4 and orthorhombic Co3V2O8 was investigated against congo red, a high %age efficiency i.e. 86% for dye degradation was obtained. Different techniques were used for the characterization of as-synthesized photocatalysts. Crystal structure, morphology, purity, composition and band gaps of photocatalysts and their heterostructures were studied by XRD, IR, SEM/EDX, and UV-Vis. DRS, UV-Vis absorption spectroscopy