Piezo-promoted Fe3+/Fe2+ cycling in Bi4Ti3O12/α-FeOOH heterojunction for enhanced Fenton-like degradation of refractory organic pollutants: A sustainable strategy and mechanism insights

In heterogeneous Fenton-like systems, the unsustainable cycle of Fe³⁺/Fe²⁺ is the primary limitation on degradation efficiency. We proposed a novel strategy for enhancing catalytic performance of heterogeneous Fenton-like system through piezoelectric effect-driven Fe³⁺ reduction. Therefore, the Bi₄Ti₃O₁₂/α-FeOOH composite was synthesized, and it had exceptional piezoelectric characteristics. A piezoelectric Fenton-like system based on Bi₄Ti₃O₁₂/α-FeOOH was constructed and achieved near-complete norfloxacin (NOR) removal (≈100 %) within 120 min. The improved electron transfer efficiency was corroborated by EIS and piezoelectric current responses. The contributions of free radicals follow order: OH > h⁺ > ¹O₂ > O₂⁻. XPS and DFT calculations revealed an electron transfer pathway from Bi₄Ti₃O₁₂ to α-FeOOH. Under mechanical stress Bi₄Ti₃O₁₂ generated electrons, which reacted with Fe³⁺ to sustain the chain reaction of Fe³⁺/Fe²⁺, ultimately promoting the heterogeneous Fenton-like reaction. A total of 12 NOR intermediates were detected, and the degradation pathway of NOR was deduced. The piezoelectric Fenton-like degradation reduces the toxicity of pollutant. Finally, the good degradation stability and practical application potential of Bi₄Ti₃O₁₂/α-FeOOH piezoelectric Fenton-like system was confirmed. This work presented the feasibility and mechanism of piezoelectric effect promoting heterogeneous Fenton-like reaction, and provided a sustainable solution for refractory organic wastewater purification.