Solar light photocatalysis using Bi2O3/Bi2SiO5 nanoheterostructures formed in mesoporous SiO2 microspheres

There have been significant efforts to find novel photocatalytic materials with improved properties, such as an extended absorption wavelength from the UV to the visible-light region. Among the semiconductors with high photocatalytic activities, considerable attention has been given to bismuth-based oxides with suitable band gaps, which provide an opportunity to harvest visible light. Herein, we report Bi2O3/Bi2SiO5 nanoheterostructures formed in mesoporous SiO2 microspheres. The as-prepared nanocomposite exhibited excellent photocatalytic activities for the decomposition of both bisphenol A and acetaldehyde under irradiation by simulated solar light. The enhanced photocatalytic activity is due to (i) the reduction in the electron-hole recombination rate because of the reduced dimensions of the photocatalyst, (ii) a more efficient utilization of the photogenerated electrons and holes as a result of the high surface area to bulk ratio of the mesoporous structure, and (iii) a better electron-hole pair separation due to the formation of the Bi2O3/Bi2SiO5 nanoheterostructure. The high efficiency in the degradation of organic pollutants under mild conditions makes the as-prepared mesoporous photocatalyst a promising candidate for photocatalytic environmental purification.