Photocatalytic activity of bismuth doped SrAl2O4 ceramic powders

Abstract The Photocatalytic activity of bismuth doped SrAl 2 O 4 ceramic powders was studied by monitoring the degradation of the Methylene Blue (MB) and Congo Red (CR) dyes in water solution under ultraviolet (254 nm) and solar irradiation. The SrAl 2 O 4 :xBi powders were synthesized by a combustion method with different Bi weight percentages. XRD patterns of these powders indicate the presence of pure monoclinic phase. SEM images of SrAl 2 O 4 :Bi powders show a morphology of polygonal irregular grains with sizes in the range of 0.2–1.9 μm. An enhancement of absorbance was observed in the UV-VIS-NIR regions as the Bi content increases. A comparison of degradation performance among samples indicates that the sample doped with 1% Bismuth produced the highest degradation rates of 0.65%/min and 0.33%/min for MB and CR dyes, respectively, under solar irradiation. When the same catalyst was used under UV irradiation, the highest degradation rates for MB and CR were 1.05%/min and 0.38%min respectively. MB and CR dyes were completely degraded (decolorized) after 130 min and 320 min under solar irradiation respectively, while total degradation of MB and CR was observed after 210 min and 360 min under UV exposure respectively. Hence, our results suggest that SrAl 2 O 4 :Bi(1%) powders could be useful for solar photocatalytic degradation of dyes in water treatment plants.