CO₂* Luminescence-Navigated Oxide Overlayer Engineering for CO Oxidation

Strong metal-support interaction (SMSI)-induced oxide overlayers critically govern the CO oxidation activity of metal-supported catalysts. However, it remains challenging to predict the optimal oxide overlayer structure in CO oxidation due to its intertwined geometric and electronic effects. To address this, we introduce the luminescence of excited-state CO₂ molecules (CO₂*)- generated during their relaxation to the ground state in the CO oxidation reaction- as a novel "navigation gauge" for determining the ideal oxide overlayer on Au nanoparticles. The CO₂* luminescence intensity in CO oxidation revealed a volcano-shaped dependence on ZnO_x overlayer coverage. More interestingly, such a volcano profile of the luminescence intensity directly aligned with the CO conversion tested in the fixed-bed reactor, demonstrating a linear correlation between luminescence intensity and catalytic activity. Therefore, the CO₂* luminescence served as an indicator for both the overlayer structure and the catalytic activity. Finally, the universality of the CO₂* luminescence-lighted strategy was validated over classical Au/MO_x systems, including Au/TiO₂-R (rutile), Au/TiO₂-A (anatase), and Au/CeO₂. It is anticipated that the CO₂* luminescence-lighted strategy not only lights up the intricate oxide overlayer structures but also provides a promising navigation tool for guiding the rational design of highly active CO oxidation catalysts, circumventing conventional trial-and-error optimization approaches.