Micellar interface modulation self-assembly strategy towards mesoporous bismuth oxychloride-based materials for boosting photocatalytic pharmaceuticals degradation

The spontaneous recombination of photogenerated carriers greatly limits the improvement of photocatalytic efficiency for bismuth oxychloride-based catalysts. Constructing porous or heterostructure photocatalysts can effectively inhibit their recombination. However, owing to the fast hydrolysis/condensation rates and uncontrollable nucleation/growth kinetics of Bi3+ species, it is difficult to achieve inorganic–organic co-assembly, and form mesoscopic structure and heterostructure. Herein, a series of mesoporous bismuth oxychloride-based materials (Bi2O3 at a stoichiometric ratio of 0 for Cl, Bi12O17Cl2, heterostructured Bi12O17Cl2/BiOCl and BiOCl) with various stoichiometry, tunable compositions and large surface areas are synthesized by a micellar interface modulation self-assembly strategy. In this strategy, Pluronic P123 and cetyltrimethyl ammonium chloride (CTAC) form P123/CTA+ composite micelles, which assemble with Bi3+ precursors by Coulomb interactions. Moreover, the Cl- ions are induced and modulated through composite micelles to involve in the slow hydrolysis and condensation of Bi3+ precursors at the hydrophilic-hydrophobic interface of composite micelles to form mesophase, thereby realizing the synthesis of mesoporous bismuth oxychloride with various stoichiometry and compositions by regulating CTAC amount. The prepared mesoporous Bi12O17Cl2/BiOCl-OV shows superior photocatalytic activity (degrade 83% within 30 min for 10 mg/L carbamazepine and 99% within 10 min for 10 mg/L ciprofloxacin), which can be ascribed to the mesoporous architecture, intimate contact heterojunction and abundant surface oxygen vacancies. This work provides a new idea and strategy for design and synthesis of high-efficiency mesoporous bismuth oxychloride-based photocatalysts.