Low-coordinated-site-mediated adsorption-migration mechanism: silver-supported zirconium dioxide-catalyzed selective...

Precise regulation of the surface coordination environment of zirconia (ZrO₂) is crucial for understanding its catalytic behavior in the selective hydrogenation of carbon-oxygen (CO) bonds. However, establishing a single-variable correlation between the morphology of the support and its surface active sites-while eliminating multivariable interference-remains a major challenge in structure-performance relationship studies. Herein, we propose a morphology-driven single-variable regulation strategy, achieving controlled adjustment of the concentration of low-coordinated ZrO sites (LCSs) on ZrO₂ simply by varying the type of precipitant used during hydrothermal synthesis. Using the selective hydrogenation of diethyl oxalate (DEO) as a model reaction, and combining in situ spectroscopic characterization with density functional theory (DFT) calculations, we reveal an LCS-capture/O_v-activation-driven "adsorption-migration" mechanism. The LCSs serve as high-density, weak adsorption sites that rapidly capture DEO molecules and thus ensure high selectivity; subsequently, at reaction temperature, the adsorbed DEO species migrate to adjacent oxygen vacancies (O_v) to complete hydrogenation. This study establishes a clear morphology-coordination-reaction-pathway correlation, providing new theoretical insights and design strategies for the rational development of efficient and tunable heterogeneous catalysts.