Boosted photocatalytic removal of tetracycline on S-scheme Bi12O17Cl2/α-Bi2O3 heterojunctions with rich oxygen vacancies

Abstract

Construction of heterojunctions and introduction of oxygen vacancies (OVs) have been regarded as well-accepted strategies to enhance photocatalytic activity. In this demonstration, novel Bi12O17Cl2/ α-Bi2O3 S-scheme heterojunctions with rich OVs were successfully constructed by a facile chlorinating-calcining route. The characterization results confirm that the concentration of OVs was significantly enhanced after ultrathin Bi12O17Cl2 nanoflakes were anchored on the surface of α-Bi2O3. The experimental results exhibit that Bi12O17Cl2/α-Bi2O3 heterojunctions prepared by 2.33 g α-Bi2O3 and 2.5 mL of 0.01 M HCl solution possess the highest photocatalytic activity in photocatalytic removal of tetracycline (TC). The enhanced photocatalytic performance of Bi12O17Cl2/α-Bi2O3 heterojunctions originates from the excellent separation and migration mobility of photoinduced carriers induced by the interaction between the interfacial electric fields and abundant OVs. Furthermore, the recycling experiments suggest that Bi12O17Cl2/α-Bi2O3 S-scheme heterojunctions have exceptional stability in TC removal. Detailed studies have shown that the photogenerated charge pairs in Bi12O17Cl2/α-Bi2O3 heterojunctions conform to an S-scheme mechanism. This work presents a deep insight into designing S-scheme photocatalysts with rich OVs to effectively treat water pollution.