Coordinating the exciton-mediated and carrier-mediated photocatalytic mechanisms of carbon nitride using acetylacetone for enhancing emerging contaminants removal

The neglect of exciton-mediated energy and electron transfer mechanisms and the lack of efficient co-catalysts are two essential obstacles to expanding the application of photocatalysis in emerging contaminant treatment. Herein, acetylacetone (AA) was indirectly excited in the visible light region with the assistance of oxygen-doped carbon nitride (OCN) and showed a unique co-catalyst effect through coordinating exciton-mediated and carriermediated energy and electron transfer pathways. Specifically, introducing AA enhances the energy transfer efficiency of OCN, promotes reactive oxygen species generation through carrier-mediated and triplet excitonmediated pathways, and improves exciton-mediated direct energy and electron transfer to diclofenac. As expected, the OCN/AA system showed superior activity for photocatalytic degradation of diclofenac and several other emerging contaminants. Hence, this study offers a ground-breaking viewpoint on the effective co-catalyst effect of AA and an in-depth understanding of how AA coordinates on multiple exciton-mediated and carriermediated photocatalytic mechanisms.