PEROVSKITE HETERO-NANOSTRUCTURES FOR SOLAR HYDROGEN GENERATION

Abstract

The performance of an efficient photocatalyst is attributed to its high light absorption, efficient charge separation, carrier transportation and surface adsorption. This study attempts to synthesise an efficient photocatalyst for hydrogen generation via water split ting under solar irradiation. Layered aurivillius perovskites have shown good photoac tivity under UV and visible spectrum. This work investigates the higher layered (n = 4, 5) aurivillius structures. In the first phase Bi6−xSrxTi3+xFe2−xO18 system has been substituted with Lanthanum. Solid state synthesis methods have been used for this sub stitution. The compounds Bi5.75−xLaxSr0.25Ti3.25Fe1.75O18 (x=0.5, 1.0) are synthesised. The substituted system shows change in energy band gap, band position and crystal dimensions. Hydrogen evolution via water splitting and dye-degradation have been in vestigated. The compounds Bi4.75LaSr0.25Ti3.25Fe1.75O18 shows higher photocatalytic activity than the parent system. To further enhance the photocatalytic activity, In the second phase of this work, heterostructure of Bi5.75−xLaxSr0.25Ti3.25Fe1.75O18 (x=0.5, 1.0) compounds are constructed with La0.7Ca0.3MnO3 and SrTiO3. Hydrothermal methods have been used to deposit the compounds. Heterostructuring increased the activity of Bi5.25La0.5Sr0.25Ti3.25Fe1.75O18 and the parent Bi5.75Sr0.25Ti3.25Fe1.75O18.