Fabrication of Sm2(WO4)3/g-C3N4 heterojunction for boosting photodegradation of methyl parathion and ofloxacin: Characteristics, mechanism insight and pathways

Abstract

This paper describes a novel Sm2(WO4)3@g-C3N4(SmW@CN) heterojunction photocatalyst system thatwas fabricated viaa simple hydrothermal route and followed by ultrasonic treatment. The crystallographic properties, physicochemical parameters, morphological features, and optical information were confirmed byP-XRD, SEM-EDX, TEM, XPS, BET, UV-DRS, and PL analysis.The SmW@CN shows fabulous photodegradation activity against hazardous methyl parathion (MP) and ofloxacin (OFX) under visible light. Energy gap values of g-C3N4, Sm2(WO4)3 and SmW@CN are 2.7, 3.3 and 2.6 eV respectively.The investigation finds that, the specific surface area of the SmW@CN nanocomposite could reach 31.5 m2g−1 when its mass ratio of g-C3N4 and Sm2(WO4)3 is 8.6 m2g−1.The complete degradation of MPand OFX was achieved within 80 and 40 min of irradiation, respectively. Interestingly, the enhanced photocatalytic properties could be attributed to the synergetic effects of Sm2(WO4)3 and g-C3N4whichinhibits the rapid recombination of e– h+charge carriers at the interface of the photocatalyst. The oxidative radicals quenching experiment portrayed the O2•−and •OH radicals that play a critical role in the photodegradation process. Furthermore, the tentative photocatalytic mechanism of SmW@CN heterojunction was ultimately provided in detail. Lastly, a feasible charge separation pathway was suggested to explain the development of the reactive oxidative species and GCMS– analysis was utilized to track the photodegradation process of OFX. In addition,catalyst laid out excellent durability over a cycle of 5th consecutively runs exhibiting only 12% reduction resulting from the fifth cycle.This work depicts versatility of the SmW@CN composite with its ability to perform photocatalysis adaptability in terms of detoxifying both organic and inorganic contaminants in waste water treatment.