Template-free synthesis of Bi2O2CO3 hierarchical nanotubes self-assembled from ordered nanoplates for promising photocatalytic applications.

In this study, we have adopted a one-step hydrothermal route to synthesize an interesting type of Bi2O2CO3 hierarchical nanotubes self-assembled from ordered nanosheets. The effects of reaction time on the morphological and structural evolution, light absorption properties, photoelectrochemical performance, and photocatalytic performance of the prepared hierarchical nanotubes were investigated. Among the products synthesized at different reaction times, the 3-hour-derived Bi2O2CO3 hierarchical nanotubes were identified to possess the highest photocatalytic performance. To promote the photocatalytic application of the as-synthesized Bi2O2CO3 hierarchical nanotubes, their performance was systematically evaluated via the photodegradation of various organic pollutants (e.g., methyl orange (MO), rhodamine B (RhB), methylene blue (MB), ciprofloxacin (CIP), sulfamethoxazole (SMX) and tetracycline hydrochloride (TC)) and the photoreduction of Cr(VI) under simulated-sunlight irradiation. Furthermore, their photocatalytic performance was also evaluated by purifying simulated industrial wastewater (i.e., a MO/RhB/MB mixed solution) at different pH values and containing different inorganic anions. Based on the experimental data and density functional theory (DFT) calculations, the involved photocatalytic mechanism was discussed.