Emerging layered BiO2−x for photocatalysis: status, challenges, and outlook
It is highly desired to develop new kinds of semiconductor photocatalysts for environmental remediation and energy production. Recently, BiO2−x, a new bismuth-based oxide has attracted considerable interest due to its narrow band gap, high number of defect sites, and its unique layered structure, which will play a significant role in photocatalysis in the future. By synthesizing BiO2−x-based nanocomposites with a thin layer structure, doped with various elements, or coupled with other semiconductors, it was demonstrated that they showed good photoactivity for H2 production, organic pollutant degradation, O2 activation, and so on. In this perspective, recently published works about bare BiO2−x, doped BiO2−x, and BiO2−x-based heterogeneous nanocomposites were summarized, including discussion about current issues, such as preparation method, non-defined structure, and poor charge separation. Finally, potential applications of BiO2−x photocatalysts were proposed in renewable energy production and environmental remediation.