0D/2D Bi2WO6:Yb3+,Tm3+/Bi12O17Cl2 S-scheme heterojunction photocatalyst with enhanced full spectrum light activity by upconversion luminescence

Abstract

To effectively utilize near-infrared light in the solar spectrum, expanding the spectral response range of photocatalysts is one of the main issues at present. Herein, a novel 0D/2D Bi2WO6:Yb3+, Tm3+/Bi12O17Cl2 S-scheme heterostructure with full spectral response is successfully synthesized through a hydrothermal method. The optimized Bi2WO6:Yb3+,Tm3+/Bi12O17Cl2 (1:1) photocatalyst degraded 68.2% and 59.1% of methylene blue (MB) and Rhodamine B (RhB) at 980 nm NIR light irradiation for 240 min, and the degradation of MB and RhB was 96.1% and 92.3% under visible light irradiation for 40 min, respectively. The enhanced photocatalytic activity could be attributed to these synergistic effects including the unique 0D/2D contact interface, the expanded photoresponse range, enhanced upconversion luminescence, as well as efficient energy transfer process between Yb3+/Tm3+ and Bi2WO6. Based on characterization and photocatalytic experiments, the introduction of Bi2WO6:Yb3+, Tm3+ can construct S-scheme heterojunctions with Bi12O17Cl2 and produce a full-spectrum response to sunlight. The result, the Bi2WO6:Yb3+, Tm3+/Bi12O17Cl2 photocatalysts possessed effective charge distribution and migration and maintained the excellent redox capacity of semiconductor materials. The hydroxyl radicals (·OH), superoxide radicals (·O2), and holes (h+) as active species played crucial roles in the degradation process. This work describes a potential method to construct S-scheme photocatalyst with great upconversion activity that possesses full spectral response for water pollution control.