Advanced oxidation processes (AOPs) have been widely accepted as an efficient and promising strategy for treating organic pollutants, is mainly dominated by hydroxyl radicals (•OH); however, its further practical application has been hindered by its low decomposition rate of H2O2. Hence, for the first time, we propose an eco-friendly and facile synthesis methodology synthesize water-soluble Co9S8 quantum dots (QDs) derived from commercial cobalt disulfide (CoS2), which can serve as excellent co-catalysts to dramatically enhance the decomposition rate of H2O2. It is demonstrated that the conversion rate of H2O2 into •OH is ca. 80.02% promoted by Co9S8 QDs, whereas the conventional Fenton process is ca. 34.9%. The result shows that unsaturated edged S atoms on the surface of Co9S8 play a pivotal role in this enhancement, where the number of protons will react with sulfur atoms to form H2S and expose reductive metallic active sites to accelerate the Fe3+/Fe2+ conversion. In addition, to tackle the issue for difficult recovery of liquid quantum dots, the magnetic Co9S8 QDs/Fe3O4 nanoparticles are particularly synthesized, which show excellent performance for degradation of 20 mg/L Rhodamine B (RhB). Moreover, the TOC degradation rate can remain stable at 80% even after five cycles. It is expected that this work will provide a new pathway of thinking in the Fenton process and impulse the usage of liquid quantum dots in practical AOPs application.
Keywords: Co(9)S(8) QDs; Co-catalytic; Fenton process; Recovery; Transition metal disulfides.
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