bismuth oxyiodide is an excellent photocatalyst with peroxidase-like activity and superior stability, enabling it to be used for the treatment of wastewater. This material has a narrow band gap and a specific layered structure that favors visible light absorption and electron-hole pair separation. It has a high thermal stability, which makes it a desirable candidate for use in solar energy conversion applications.
In this article, we report the synthesis and characterization of a new type of bismuth oxyiodide single crystal functional material with numerous mesopores by using a mild heat-treatment process. The average diameter of the mesopores was 9.2 nm and they were able to effectively catalyze RhB and salicylic acid mineralization under visible light irradiation.
SEM images and TEM analyses show that the mesopores of this material are formed by intercalation between Bi 2 O 2 slabs with a specific configuration. This type of mesopore is a common feature of the Bi 2 O 2 ion-selective nanoporous structures.
XPS analysis of the films suggests that these mesopores are not caused by the adsorbed organic contaminants or moisture, but rather by changes in the composition of iodine and oxygen at the surface. The surface atomic fraction of iodine decreased significantly from the nonannealed film to the vacuum-annealed film, while the fraction of oxygen increased.
These results indicate that the crystalline morphology and facets of these mesopores play an important role in the photocatalytic activity of the Bi 2 O 2 ion-selective materials. Moreover, they are able to promote the formation of photogenerated electrons and holes that can contribute to the NO oxidation reaction.