Hexagonal phase MoO3 with three-dimensional crystal structure as heterogeneous photocatalyst for tetracycline degradation: Degradation pathways and mechanism

Molybdenum trioxide (MoO3) has attracted tremendous interests as a promising photocatalyst for wastewater treatment due to its non-toxicity, excellent stability and good charge transfer efficiency. Herein, the crystals of h-MoO3 (complex 1) has been synthesized and characterized by X-ray single crystal diffractometer measurement, demonstrating a three-dimensional framework. Complex 1 displays excellent photocatalytic activity, stability and resuability toward tetracycline (TC) photodegradation with rate of 80.0 % (120 min), which is much higher than that of α-MoO3 samples (35.1 %, 120 min) due to different crystalline phase structure. The charge transfer from O centers to Mo centers in 1 is vital for enhanced degradation efficiency, which has been evidenced by XPS spectra before and after photodegradation. The degradation products and the degradation pathways have been speculated through liquid chromatography–mass spectrometry (LC–MS). This work presents an example of studying structure–activity relationship of metal oxide for antibiotic photodegradation.