Toward Robust Single-Atom CeO x on Ni via SMSI-Induced Redispersion of CeO2 Nanoparticles for Enhanced Phenolic Hydrogenation

Abstract Modulating SMSI enables inverse single-atom MOx/M interfaces, overcoming limitations of SACs and inverse catalyst architectures. This study reports an inverse CeO2/Ni catalyst that undergoes SMSI-driven restructuring under hydrogen reduction. CeO2 nanoparticles migrate onto the Ni surface, forming a conformal CeOx overlayer and inducing significant metal−oxide electron transfer. At low CeO2 loadings (<5 wt %), AC-STEM and operando/quantitative probes confirm that Ce redistributes into atomically dispersed CeOx species. The reconfigured CeOx−Ni interface provides ideal active sites for phenolic hydrogenation: the catalyst delivers >90% yield and selectivity to cyclohexanols from phenol and substituted phenols; activity scales linearly with CeO2 loading, while the activation energy remains constant. In situ spectroscopic and kinetic analyses, supported by the density functional theory, indicate that interfacial CeOx species stabilize phenyl−O−Ce intermediates and lower the hydrogenation barrier, promoting aromatic ring saturation. These insights offer an effective route for designing atomically dispersed oxide−metal interfaces via SMSI-driven dynamics.