Ternary TiO2@Bi2O3@TiO2 hollow photocatalyst drives robust visible-light photocatalytic performance and excellent recyclability

The development of visible-light photocatalysts with excellent catalytic activity and recyclability still remains a big challenge. Here, we present a facile template and self-assemble strategy to design new confined ternary photocatalyst by embedding Bi2O3 (p-type) into hierarchical hollow TiO2 (n-type) spheres (TiO2@Bi2O3@TiO2). The obtained TiO2@Bi2O3@TiO2 photocatalyst exhibits strong visible-light absorption and efficient charge separation due to its unique n-p-n heterojunction, effectively driving the complete degradation (100%) of tetracycline according to the characteristic peak (∼350 nm) and TOC results of TC under visible light (λ > 420 nm). Interestingly, the introduction of confinement effect considerably promotes cyclic stability, especially in a strong acid (pH=3.0) or alkali (pH=11) environment. Moreover, the photodegradation intermediates and pathways are demonstrated by LC-MS measurement. This finding provides a new idea to design other confined photocatalysts with a ternary heterojunction for clean energy and environment applications.