From one to three: in-situ transformation of Bi3O4Cl to Bi/BiOCl/Bi3O4Cl core-shell nanocomposites with highly photocatalytic activities

Abstract

Although many attempts have been made to construct ternary heterojunctions, however, the currently reported composites suffer from complicated preparation processes and poor interface matching. Inspired by the BiOCl and Bi3O4Cl have quite similar [Bi2O2]2+ structural units, the Bi/BiOCl/Bi3O4Cl ternary core-shell heterostructured photocatalyst were constructed by in-situ transformation method. During the reaction process, the external layer of Bi3O4Cl was dissolved, and the BiOCl nanosheets were recrystallized in situ on the surface of Bi3O4Cl. At the same time, the ethylene glycol reduced part of Bi3+ to Bi and sequentially deposits on the surface of BiOCl. Compared with pure Bi3O4Cl, the tight heterojunction formed between Bi/BiOCl and BiOCl/Bi3O4Cl increased the charge carrier concentration and effectively promoted photogenerated electrons and holes separation. Therefore, the composite photocatalysts exhibit extremely high efficiency in degrading organic pollutants, the photocatalytic degradation of organic pollutants (ciprofloxacin and rhodamine B) with 7% Bi/BiOCl/Bi3O4Cl had the highest rate constants k of 0.029 and 0.079 min−1, which about 97 and 41 times higher than that of the pure Bi3O4Cl photocatalyst. This work provides a feasible method for constructing tightly bound composite nanomaterials by simple in situ transformation methods, which can be used as photocatalysts and electrocatalysts, among others.