Evaluating the Photocatalytic Activity of Ba₂FeNbO₆

Chinchu Gibi

Department of Chemistry, National Institute of Technology, Tiruchirappalli 620 015, Tamil Nadu

Dr. N. Lakshminarasimhan

Functional Materials Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630 003, Tamil Nadu

ABSTRACT

Solar energy is one of the viable and renewable energy sources to meet the ever increasing global energy demand. In addition to electricity production using solarcells, solar energy can also be used to produce hydrogen fuel by splitting water and in the environmental remediation for the removal of toxic pollutants present in water using semiconductor photocatalysis. Semiconductor photocatalysis is a process in which solar energy excite the valence band electron in the semiconductor leaving behind holes, which combine with surface hydroxyl groups resulting in the production of hydroxyl radicals oxidizing the organic pollutant molecules . Pollutants also directly react with the valence band holes and get oxidized. The conduction band electron can also produce superoxide radicals from dissolved oxygen in water, which are powerful oxidants of organic and inorganic pollutants. The wide band gap (3.2 eV) limits the application of TiO₂, a well- known photocatalyst, in the visible spectrum of solar light and thus there is a search for alternative semiconducting material with narrow band gap, long term stability and with suitable valence and conduction band positions. Iron oxide based materials with narrow band gaps are suitable materials for visible light photocatalysis. From the literature,it has been found that there is one report in which the visible light photocatalyticH₂ production activity of Ba₂FeNbO₆ was studied in the solid solution SrTiO₃-Ba₂FeNbO₆ .Hence, Ba₂FeNbO₆ with an optical band gap of 2.28 eV can be a potential candidate as a visible light active photocatalyst. The present work involves the synthesis of Ba₂FeNbO₆ by flux method, characterization using powder XRD, FT-IR and Laser Raman spectroscopic techniques,scanning electron microscopy, and evaluating its photocatalytic activity towards dye removal.

Keywords: Photocatalyst, Oxide, Flux Method, Powder X-ray diffraction, EPR, Methylene Blue