A highly efficient perovskite oxides composite as a functional catalyst for tetracycline degradation

Abstract

• A steady heterojunction interface between Bi 4 Ti 3 O 12 and LaCoO 3 was exquisitely constructed for the boosting oxidation of tetracycline. • A direct Z-scheme heterostructure with highly efficiency electron transport capability can be founded in this heterojunction. • This heterojunction system between Bi 4 Ti 3 O 12 and LaCoO 3 is first applied for the photocatalytic oxidation of tetracycline. • The degradation activity of LCBT-2 for SMX reaches 87.8% (100 min) and its stability can maintain 78.4% even after 4 cycles. Of large amounts of catalysts that have been developed to date for high catalytic activity and durability, perovskite oxides have appealed the attention due to their inherent performance as well as structural flexibility. Especially, the aurivillius perovskites could be a fantastic “pollutants oxidizer”. Therefore, we designed a novel catalyst, LCBT-2 (LaCoO 3 :Bi 4 Ti 3 O 12 = 1:2, mole ratio), composed by ultrathin aurivillius perovskite Bi 4 Ti 3 O 12 nanosheets and typical perovskite LaCoO 3 particles. This new type of composite catalyst appeared exceptional catalytic activity and high stability for tetracycline (TC) degradation. The activity of TC degradation by LCBT-2 reached 87.8% and the activity could maintain 78.4% after 4 cycles, proving the high durability of LCBT-2. A proposed mechanism for the synergistic effects between Bi 4 Ti 3 O 12 and LaCoO 3 was analyzed by active species trapping experiment and electron paramagnetic resonance (EPR). Moreover, the possible pathways of TC degradation were proposed according to the results of high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS). This study aims at the application of coupled perovskite oxides as photocatalysts for TC degradation and reveals the reason of synergistic effects between the two part of perovskite oxides (Z-scheme heterojunction interface) by experiments and in-depth mechanistic analysis.