Boosting Benzene Hydroxylation via Hydroxyl-Migration-Mediated Synergy of Spatially Isolated Cu and La Single Atoms

Abstract Single-atom catalysts (SACs) offer high atom utilization efficiency and chemical selectivity for benzene hydroxylation using H2O2, yet their isolated mononuclear active sites are typically insufficient to mediate the two consecutive elementary steps required for benzene hydroxylation, namely, H2O2 activation and inert C–H bond cleavage. Herein, we report a dual single-atom catalyst featuring spatially isolated Cu and La single atoms anchored on an SBA-15 support (CuLa/SBA), synthesized via a direct one-pot hydrothermal strategy.The nonadjacent Cu–La single atoms with interatom distances of ∼4.6 Å were confirmed by HAADF-STEM, EXAFS fitting, and corresponding DFT simulations. Combined electrochemical analyses and DFT calculations elucidate the synergistic mechanism between the spatially separated Cu and La single atoms. Specifically, the Cu sites selectively activate H2O2 to generate hydroxyl radicals (•OH), which subsequently migrate to the adjacent La sites, leading to the formation of La-OH species that efficiently activate the inert C–H bond of benzene. Benefiting from this, the developed CuLa/SBA shows lower H2O2 and benzene activation barriers than the Cu/SBA counterpart. As a result, CuLa/SBA achieves TON ∼1.5 times higher than that of Cu/SBA while maintaining a phenol selectivity of 96.9%. Moreover, the catalyst retains its catalytic performance over 10 consecutive reaction cycles. This work provides the conceptual demonstration that hydroxyl migration can mediate catalytic synergy between spatially isolated dual single atoms, which provides an alternative strategy for dual single-atom catalysts tailored to multistep selective oxidation reactions and offers fundamental insights into nonadjacent synergistic interactions in heterogeneous catalysis.