Crystal Facet Induced Single-Atom Pd/Cox Oy on a Tunable Metal-Support Interface for Low Temperature Catalytic Oxidation.

Atomic dispersed metal sites in single-atom catalysts are highly mobile and easily sintered to form large particles, which deteriorates the catalytic performance severely. Moreover, lack of criterion concerning the role of the metal-support interface prevents more efficient and wide application. Here, a general strategy is reported to synthesize stable single atom catalysts by crafting on a variety of cobalt-based nanoarrays with precisely controlled architectures and compositions. The highly uniform, well-aligned, and densely packed nanoarrays provide abundant oxygen vacancies (17.48%) for trapping Pd single atoms and lead to the creation of 3D configured catalysts, which exhibit very competitive activity toward low temperature CO oxidation (100% conversion at 90 °C) and prominent long-term stability (continuous conversion at 60 °C for 118 h). Theoretical calculations show that O vacancies at high-index {112} facet of Cox Oy nanocrystallite are preferential sites for trapping single atoms, which guarantee strong interface adhesion of Pd species to cobalt-based support and play a pivotal role in preventing the decrement of activity, even under moisture-rich conditions (≈2% water vapor). The progress presents a promising opportunity for tailoring catalytic properties consistent with the specific demand on target process, beyond a facile design with a tunable metal-support interface.