Au-modified In2O3 nanoparticles for photocatalytic degradation of diverse antibiotics

Abstract

The co-existence of diverse antibiotics in wastewater systems necessitates the development of multifunctional catalysts for simultaneous pollutant remediation. While indium oxide (In₂O₃) presents advantages as a semiconductor photocatalyst through its high electrical conductivity, low resistivity, and inherent oxygen vacancies, practical applications in broad-spectrum pollutant degradation remain constrained by rapid charge carrier recombination and limited visible-light utilization efficiency. To address these challenges, we developed plasmonic Au nanoparticle-decorated In₂O₃ composites (Au_NPs/In₂O₃) via a controlled in-situ reduction strategy. Systematic characterization revealed that the localized surface plasmon resonance (LSPR) effect of Au nanoparticles synergistically enhanced UV–vis absorption characteristics while effectively suppressing photogenerated electron-hole recombination, as evidenced by photoelectrochemical analyses including transient photocurrent response and electrochemical impedance spectroscopy. The optimized Au_NPs/In₂O₃ hybrid demonstrated exceptional photocatalytic performance, achieving 99.0 % degradation efficiency for both ofloxacin and tetracycline antibiotics under visible-light irradiation, along with remarkable cycling stability (>90 % efficiency retention after three cycles) and practical applicability across varied water matrices. Mechanistic investigations through radical trapping experiments identified the predominant roles of hole (h⁺) and superoxide radical (·O₂⁻) species in the multi-pathway degradation processes. This study not only provides an effective strategy for engineering plasmon-enhanced In₂O₃ photocatalysts but also establishes a methodological framework for developing multifunctional catalytic systems for environmental remediation.