Green Synthesis of Iron-Doped Carbon Dots Derived from Ferrous Gluconate as Efficient Photocatalysts for Visible-Light-Promoted Peroxymonosulfate Activation for Photogenerated Hole Mediated Ace Degradation

This work first put forward ferrous gluconate (FG) as a precursor to facilely prepare iron-doped carbon dots (Fe-CDs) with abundant catalytic active sites for the degradation of acetaminophen (ACE) by photoactivation of PMS. Within 20 minutes, Fe-CDs/PMS/Vis system can achieve a 100% degradation of ACE (15 μM) with low-addition of PMS (0.2 mM) and Fe-CDs (12 μg/L). The mediating role of h+ on the generation of active species in the photo-assisted PMS activation oxidation process is elaborated, which has long been overlooked. DFT calculations are used to in-depth analysis of h+ mediation nonfree radical (1O2) and free radical pathway (•OH). The results show that compared to CDs, Fe3+ sites on Fe-CDs can effectively reduce the activation energy of PMS, leading to a greater advantage of h+ in activating PMS. This work provides experimental and mechanistic insights for further research on visible-light-assisted Fe-CDs/PMS activation and h+ mediated advanced oxidation process.