Heterogenization of Fe³⁺ Ions on Chiral Carbon Dots With Enhanced Activity and Stability in DOPA Oxidation

The heterogenization of homogeneous catalysts represents a major research direction in modern green catalysis, as it combines the high activity and selectivity features of molecular catalysts with the high stability and facile recyclability benefits of solid materials. A common drawback in most heterogenized catalyst systems is the significant decrease in catalytic activity compared to their homogeneous counterparts. Herein, we propose a facile strategy to heterogenize Fe³⁺ ions through coordination with the terminal ─COO^- groups of serine-derived chiral carbon dots (C-CDs), forming a heterogeneous catalyst with COO^-─Fe³⁺ active sites. The resulting Fe-CDs exhibit excellent stability across a broad pH range and display markedly enhanced peroxidase-like catalytic activity toward dihydroxyphenylalanine (DOPA) oxidation by 278.53% in average compared to the homogeneous Fe³⁺ catalyst. By combining excellent catalytic efficiency with well-resolved active-site architectures, the CDs-based ion-coordination-driven transition from homogeneous to heterogeneous catalysis successfully avoids the activity loss commonly linked to catalyst heterogenization.