Zinc oxide films (ZnO) were synthesized by the spray pyrolysis technique using zinc acetate as precursor salt. Afterwards, bismuth oxide (Bi2O3) dots (2 mm in diameter) were deposited on the surface of the ZnO thin films by magnetron sputtering forming a hybrid photocatalyst. X-ray diffraction, profilometry, and scanning electron microscopy were used to characterize the films. The characterization showed that the ZnO films presented a hexagonal wurzite structure and nanoflake morphology while the Bi2O3 dots presented the cubic delta phase and nanograin morphology. The photocatalytic activity for the hybrid material was evaluated testing the degradation of 5 ppm indigo carmine dye solution (C16H8N2Na2O8S2) under ultraviolet and white light. The dye degradation and the kinetic of the reaction were estimated using the variation of the corresponding absorption band as a function of the irradiation time. The results pointed out that the photocatalytic activity of the ZnO with and without Bi2O3 dots was similar using UV light but under white light illumination, the mechanism was different and the photodegradation is slightly larger with the hybrid material. This is also confirmed by the analysis of the total organic carbon, which showed about 30% more mineralization with the hybrid material. These results suggest that the proposed design of the two semiconductor films works as a heterojunction.

Photocatalytic activity enhancement of ZnO thin films under visible light using Bi2O3 dots

253rd National Meeting (2017)

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