Characterization of the Photocatalytic Activity of Bismuth Oxychloride Nanostructures

Bismuth oxychloride materials were synthesized by a one-step procedure with high purity precursors with variation of the pH from 1 to 6. The materials were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Brunauer Emmett Teller measurements, and photoluminescence. Photocatalytic properties were characterized by the degradation of methylene blue with visible light from a 100W lamp and natural sunlight. All samples contained the tetragonal phase with platelet structures. The thickness of the platelets was sensitive to pH during synthesis and increased from 97 to 227nm with an increase in pH. The photoactivity of the sample decreased with an increase in pH. The highest photocatalytic activity of 0.00295min(-1) for the 100W electric lamp and 0.00316min(-1) for sunlight was observed for the material prepared at pH 1. The photocatalytic activity values of these materials were approximately one order or magnitude higher than titanium dioxide in the visible region. Photoluminescence studies confirmed the presence of mid-band gap states that enabled the material to absorb light in the 400 to 450nm region.