Rational Design of Inverted F‐Type Heterojunctions for Photocatalytic Emerging Contaminant Degradation

Abstract The development of efficient photocatalytic systems for antibiotic degradation remains hindered by the inherent limitations of conventional heterojunctions, particularly the rapid charge recombination associated with Type‐I band alignments. Herein, we report an inverted F‐type heterojunction composed of ZnWO ₄ /In ₂ S ₃ (ZWO/IS) that delivers exceptional photocatalytic performance while preserving strong oxidation potentials. By using work function engineering, we establish a built‐in electric field that facilitates asymmetric charge separation, with photogenerated electrons from directed ZWO to IS and holes retained in ZWO to drive oxidative reactions. This unique charge transfer mechanism is directly captured via in situ X‐ray photoelectron spectroscopy (XPS), Kelvin probe force microscopy (KPFM), revealing a marked reduction in carrier recombination lifetime compared to pristine IS. The ZWO/IS heterojunction achieves outstanding degradation efficiency for tetracycline hydrochloride (TCH), with three distinct detoxification pathways elucidated through high‐performance liquid chromatography‐mass spectrometry (HPLC‐MS) and density functional theory (DFT) calculations. Comprehensive toxicity assessments, including microbial viability tests, phytotoxicity assays, and mammalian cell studies, confirm complete detoxification, with degradation by‐products exhibiting negligible developmental toxicity and mutagenicity. This work positions inverted F‐type heterojunctions as transformative platforms for photocatalytic water treatment, effectively integrating interfacial band engineering, scalable reactor design, and process optimization to bridge the gap between mechanistic insight and real‐world applications.