Interfacial Anchoring Ultrafine CuO x Nanoparticles on CeO 2 via Coordination Chemistry to Stabilize Cu + -O v -Ce 4+ Active Sites for CO Preferential Oxidation

The development of ultrafine metal oxide nanoparticles anchored on reducible oxide supports with precisely engineered interfacial active sites has emerged as a critical frontier in heterogeneous catalysis. However, conventional synthesis strategies struggle to reconcile high loading with ultrafine dispersion, often leading to nanoparticle aggregation and compromised stability. Herein, we present a coordination chemistry-driven strategy integrating the hard–soft acid–base principle with a water-etching process to synthesize ultrafine CuOx nanoparticles anchored on CeO2. By exploiting the differential coordination affinities of Ce3+ and Cu2+ with carboxyl ligands in a bimetallic BTC precursor, selective segregation during solvothermal synthesis was achieved. Ce3+ formed a stable framework with carboxyl groups, while Cu2+ underwent a hydrolysis-induced migration to surface defect sites. Regulating the Cu2+/Ce3+ ratio enabled precise control over CuOx dispersion, interfacial Cu–O–Ce bonding, and local structure. The optimized catalyst exhibited a remarkable Cu loading of 21.94% with high dispersion, lattice distortion, and enhanced metal–support interactions. Notably, the designed catalyst demonstrated exceptional stability under H2-rich streams, which achieved a CO conversion enhancement from 67.4 to 77.7% over 40 h through the interfacial stabilization of metastable Cu+-Ov-Ce4+ active configurations. Advanced characterization and density functional theory (DFT) calculations revealed that the enhanced interfacial Cu–O–Ce interactions and unsaturated coordinated CuOx species facilitated electron transfer, oxygen activation, and CO adsorption, synergistically boosting the catalytic performance via the Mars–van Krevelen mechanism. This work establishes a rational coordination chemistry-guided paradigm for designing high-performance catalysts with precisely engineered active sites.