Domino effect enables dynamic electronic structure evolution for stable and efficient water purification

The purification of water contaminated by persistent organic pollutants remains a critical global challenge, largely due to the intrinsic trade-off between high catalytic activity and long-term stability in advanced oxidation processes. Despite the tremendous potential of single-atom catalysis, its traditional static design strategies cannot adapt to dynamic and multi-step reactions. Here, we break the limitation of this static design by reporting a domino catalysis within a heteronuclear MgCo dual-single-atom catalyst. In this system, the Mg site selectively photoreduces O₂ to H₂O₂ under light irradiation. This in-situ generated H₂O₂ and its derived surface hydroxyl groups act as dynamic modulators, progressively tailoring the electronic structure of the adjacent Co site. This on-demand electronic refinement optimally lowers the energy barriers for subsequent peroxymonosulfate activation and radical desorption, thereby driving efficient pollutant degradation while intrinsically stabilizing the Co center against leaching. Experiments and theoretical calculations elucidate that this seamless and spatially ordered cascade avoids competitive adsorption and maximizes efficiency. The system exhibits the highest normalized rate constant of 595.3 min^-1 M^-1 among various refractory contaminants over thirty regeneration cycles, outperforming the most state-of-the-art catalytic systems. This work introduces a dynamic and self-evolving catalytic approach that breaks the traditional activity-stability trade-off, suggesting a potential pathway toward effective and sustainable water purification technologies.