Synthesis of bismuth-containing photocatalyst by spray pyrolysis and their characteristics

Abstract

Alternative energy and environmental pollution problems are serious global issues and one of the solution is the photocatalyst. Conventional photocatalytsts such as $TiO_2, SrTiO_3, BaTiO_3, ZnO$ and ZnS are only able to have activity under UV light which occupies the very small portion in the sun light. Therefore, to broaden the active region of photocatalyst and use widely, the photocatalyst activated under visible light is needed to develop. In this work, the Bismuth-containing phtocatalysts are the attractive materials to satisfy the requirements due to the effect of $Bi^{3+}$ ion. Spray pyrolysis which has some advantages such as high purity of product, uniformity of particle size and shape, convenience to make multicomponent product and etc. was used to synthesize the materials. Additionally, for $BiVO_4$ photocatalyst, PO4 doping and composite with cobalt oxide were conducted to increase the photocatalytic activity. As a result, all Bismuth-containing photocatalysts were well synthesized by spray pyrolysis and showed enhanced activities under visible light irradiation compared with other synthesis methods. Also, 0.5 mol % doped BiVO4 showed 1.17 times increased activity for degradation of methylene blue and 1.2 wt.% $CoO_x/BiVO_4$ composite had 1.43 and 1.29 times improved activity for methylene blue and rhodamine B degradation, respectively. Finally, prepared $Bi_3NbO_7$ was possible not only to degrade organic dyes also to evolve the $H_2$ gas from water splitting.