Engineering of BiVO4/MIL-88 A(Fe)-C Composite for Synergistic Degradation of Tetracycline Over Piezophotocatalytic and Photo-Fenton Reactions

This work discusses the fabrication of a robust stable organic MIL-88 A(Fe) framework (MAF) assembled with visible-light-induced BiVO₄ and carbon nanomaterials to establish integrated piezophotocatalytic system. The ternary BiVO₄/MIL-88 A(Fe)-C (Bi/MAF-C) catalyst was precisely characterized by various sophisticated technologies. The Bi/MAF-C composite revealed a powerful piezophotocatalytic activity (95.7%) towards tetracycline (TC) antibiotic in a short reaction time (40 min). Our composite exhibited the highest TC degradation rate (0.06460 min⁻¹), far exceeding the binary Bi/MAF, BiVO₄, and MIL-88 A(Fe) by 1.45, 2.78, and 3.8, respectively. The improved performance was associated with the multifunctional mechanisms of Bi/MAF-C in one integrated system. MIL-88 A(Fe) showed excellent response to piezoelectric effects, generating an internal electric field that further extended the photocarrier lifetime. Besides, BiVO₄ contributes to consuming wider visible light wavelengths due to its moderate band gap energy, synergy improving the piezophotocatalytic reaction. The MIL-88 A(Fe) component implies a robust photo-Fenton effect by activating H₂O₂ to generate ^•OH radicals, enhancing the oxidative degradation of pollutants under light irradiation. Additionally, further improvement in catalytic mechanism was obtained by carbon nanosheets, which act as an efficient electron conductor, accelerating the transfer of photocarriers in the Z-scheme heterojunction. The radical experiments confirmed the predominant role of ^•OH and ^•O₂⁻ in TC decomposition, further supporting the Z-scheme conception. In conclusion, this integrated piezophotocatalytic system reflects a promising strategy towards designing highly efficient multifunctional catalysts to control environmental pollution with enhanced efficiency.

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