Carbon Quantum Dots Induced Ultrasmall BiOI Nanosheets
with Assembled Hollow Structures for Broad Spectrum Photocatalytic
Activity and Mechanism Insight
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Abstract
Carbon
quantum dots (CQDs) induced ultrasmall BiOI nanosheets with
assembled hollow microsphere structures were prepared via ionic liquids
1-butyl-3-methylimidazolium iodine ([Bmim]I)-assisted synthesis method
at room temperature condition. The composition, structure, morphology,
and photoelectrochemical properties were investigated by multiple
techniques. The CQDs/BiOI hollow microspheres structure displayed
improved photocatalytic activities than pure BiOI for the degradation
of three different kinds of pollutants, such as antibacterial agent
tetracycline (TC), endocrine disrupting chemical bisphenol A (BPA),
and phenol rhodamine B (RhB) under visible light, light above 580
nm, or light above 700 nm irradiation, which showed the broad spectrum
photocatalytic activity. The key role of CQDs for the improvement
of photocatalytic activity was explored. The introduction of CQDs
could induce the formation of ultrasmall BiOI nanosheets with assembled
hollow microsphere structure, strengthen the light absorption within
full spectrum, increase the specific surface areas and improve the
separation efficiency of the photogenerated electron–hole pairs.
Benefiting from the unique structural features, the CQDs/BiOI microspheres
exhibited excellent photoactivity. The h<sup>+</sup> was determined
to be the main active specie for the photocatalytic degradation by
ESR analysis and free radicals trapping experiments. The CQDs can
be further employed to induce other nanosheets be smaller. The design
of such architecture with CQDs/BiOI hollow microsphere structure can
be extended to other photocatalytic systems