Preparation of catalytically active bismuth tungstate: effects of organic additives and dopants

Bismuth tungstate (Bi2WO6) with dominant orthorhombic crystalline phase was prepared using hydrothermal procedure. Introducing organic species including ethylenediamine-tetraacetic acid (EDTA) and polyacrylic acid (PAA) into the synthesis media leads to obtain particles with various sizes, different morphologies and distinctive adsorptive behaviours. Effects of adding lanthanum or iodine as dopants for the structural modifications of bismuth tungstate were also investigated. The prepared materials were characterised using structural, textural and microscopic techniques. The photocatalytic activities of the prepared samples were investigated using methylene blue and 2,4,6-trichlorophenol as probe molecules. Two different light sources (UV-A and visible) were tested. It was found that particle size and subsequently catalytic efficiency of the prepared catalysts can be affected by alteration of synthesis conditions. Those catalysts produced in the presence of EDTA and PAA showed better catalytic activity under irradiation of both light sources. Better adsorptive and photocatalytic activities were also observed for La-doped samples.