Tailoring bidirectional electronic transfer interaction tunnels triggers sustainable and high activity of ozone catalysis for water purification

Heterogeneous catalytic ozonation shows promise in destroying organic pollutants in water, yet developing catalysts with both high activity and stability remains challenging. In this study, we propose a catalyst design strategy involving the anchoring of electron-sharing sites near single-atom sites to construct bidirectional electron transfer interaction tunnels. The developed catalyst (MnN3–Fe1@FeN4) features Fe1@FeN4 atomic clusters as electron-sharing sites, coordinated Mn single-atom centers through shared nitrogen bridges, successfully establishing a synergistic system. The design not only enables rapid electron supply to ozone (i.e., the internal electron transport), reducing electron loss at single atoms through shared electron flow, but also facilitates electron transfer from pollutants to the catalyst via surface reactive species (i.e., the external electron transport), compensating for the electron depletion of active sites. By taking advantage of the dual bidirectional electronic transport interactions tunnels, MnN3–Fe1@FeN4 exhibits an extraordinary catalytic activity towards ozone, achieving over three times higher reactivity than Fe and Mn single atom catalyst and 2–4 orders of magnitude higher reactivity than conventional metal oxides. Moreover, the sustainability of the ozone catalytic activity surpasses almost all of the state-of-the-art catalysts. A catalytic ozone fixed-bed reactor with this catalyst has run continuously for over 260 h, treating 3125 times the bed volume of actual wastewater. Our work unveils a critical role of atomic clusters in modulating catalyst activity and long-term stability in heterogeneous catalytic ozonation, which could inspire innovative material design for more sustainable water purification applications.