Mn single atoms for one-electron photoozonation of aqueous organics

Photocatalytic ozonation offers a potential approach for highly efficient organic degradation by in-situ generation of reactive •OH via electron reduction of ozone. Herein, we synthesized a Mn single atom photocatalyst for promoting the •OH generation from O3 activation under visible light irradiation. Theoretical calculation and experimental studies reveal that Mn single atoms on carbon nitride significantly promote the excitation and transfer of photo-generated electrons, making charge carriers enriched around MnN4 sites and shortening their migration path to participate in surface reactions. Meanwhile, Mn single atoms serve as adsorption and catalytic sites for O3, favoring a fast one-electron-reduction reaction kinetics. More importantly, the trade-off between the number of available electrons and active sites in photocatalytic performance was observed from regulating the density of Mn single atoms. This work offers an intriguing regulation strategy for enriching surface charges on single atom catalyst interface toward efficient •OH production and removal of aqueous organics. [Display omitted] •Mn single atom catalysts demonstrate high performance in photocatalytic ozonation.•The anchored Mn single atoms enrich photo charge carriers for promoting O3 adsorption.•One-electron reduction path ensures efficient O3 activation to hydroxyl radicals.•A higher Mn single atom density favors higher photocatalytic performance.