Preparation of Ce0.9Zr0.1O2/SnIn4S8 composite photocatalyst and its degradation of typical antibiotic pollutants

Abstract

Considering the high environmental risk, the remediation of antibiotic pollutants attracted numerous attentions. In this work, a novel photocatalyst, Ce_0.9Zr_0.1O₂/SnIn₄S₈, was fabricated by in situ precipitation and hydrothermal method and then applied to the degradation of norfloxacin under the irritation of visible light. The SEM, TEM, XRD, XPS, and electrochemical results clearly showed that the n-type heterojunction between Ce_0.9Zr_0.1O₂ and SnIn₄S₈ was successfully constructed, which greatly reduces the recombination of the photogenic electron and holes, leading to the improvement of photocatalytic performance and stability (recycled over eight times). Besides, the Ce_0.9Zr_0.1O₂/SnIn₄S₈ composite also exhibited good ability to mineralize norfloxacin. Under the optimal condition (pH 3, 1 g L⁻¹ of 10% Ce_0.9Zr_0.1O₂/SnIn₄S₈, and 8 mg L⁻¹ of initial norfloxacin concentration), norfloxacin could be fully and rapidly degraded in 60 min, and completely mineralized in 4 h (99.3 ± 1.7%). LC-QTOF-MS results evidently displayed eight intermediates during norfloxacin degradation. In addition, with the attack of the reactive oxygen species (h⁺, •OH, and •O₂⁻), norfloxacin could be effectively decomposed via deoxygenation, hydroxylation, and carboxylation reactions. Notably, compared to photodegradation, the photocatalytic process could completely eliminate the norfloxacin from water because it could avoid the accumulation of toxic byproducts.