Bile Acid-Assisted Self-Assembly of BiOCl Nanosheets into Hierarchical Structures for Photocatalytic Degradation in Water Treatment

In this study, we present a facile and eco-friendly method to synthesize hierarchical, flower-like bismuth oxychloride (BiOCl) microstructures with nanoscale features using bile acids (BAs) as directing agents in an aqueous environment at room temperature. The chirality of BAs significantly influenced the helical stacking of nano- and microplates, resulting in the formation of nanosheet flowers with controllable structures and distinct nanoscale characteristics. Time-dependent X-ray diffraction and scanning electron microscopy studies elucidated the growth process of these nanoscale-influenced nanosheet flower structures, which adhered to the Ostwald ripening process. The as-synthesized BiOCl nanosheet flowers, with their unique nanoscale attributes, exhibited superior photocatalytic performance for the degradation of rhodamine B under visible-light irradiation. Moreover, the incorporation of BiOCl nanosheet flowers with nanoscale features into an agarose/chitosan aerogel formed a monolithic shape that offered high efficiency and easy recyclability for wastewater treatment applications. Our work introduces a promising strategy for designing and creating hierarchical nanosheet structures with significant nanoscale properties using biobased materials, with potential applications in photocatalysis and water treatment.