Synergistic and efficient photocatalytic degradation of rhodamine B and tetracycline in wastewater based on novel S-scheme heterojunction phosphotungstic Acid@MIL-101(Cr).

To efficiently treat rhodamine B (RhB) and tetracycline (TC) in wastewater, MIL-101(Cr) was prepared by hydrothermal method and encapsulated with phosphotungstic acid (H ₃ PW ₁₂ O ₄₀ , abbreviated as PTA) to form an S-scheme heterojunction PTA@MIL-101(Cr)-x (P@M-x, x = 50, 100, 150, 200). The experimental results showed that after 180 min under visible light at pH 7, the degradation rates of RhB and TC were 97.81% and 99.9%, respectively. Meanwhile, the cycling experiments have showed that the P@M-100 S-scheme heterojunction exhibits good stability. Density Functional Theory (DFT) calculations theoretically verified the experimental results and elucidated the electrons migrate to MIL-101(Cr) and hole enrichment on the PTA surface. It was also revealed that the P@M-x photocatalyst belongs to the S-scheme heterojunction. Moreover, •O ₂ ^- and h ⁺ had been identified as the main active constituents during the photocatalytic degradation process. The synergistic effect of MIL-101(Cr) and PTA enhances the visible light absorption of P@M-x S-scheme heterojunction, resulting in more efficient electron transfer ability and faster photoreaction rate, thereby improved its photocatalytic performance. This study provides a potential solution for addressing aromatic pollutants in water.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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