A Tale of Two Sites: Neighboring Atomically Dispersed Pt Sites Cooperatively Remove Trace H2 in CO‐Rich Stream

Single‐atom catalysts (SACs) exhibit distinct catalytic behavior compared with nano‐catalysts because of their unique atomic coordination environment without the direct bonding between identical metal centers. How these single atom sites interact with each other and influence the catalytic performance remains unveiled as designing densely populated but stable SACs is still an enormous challenge to date. Here, a fabrication strategy for embedding high areal density single‐atom Pt sites via a defect engineering approach is demonstrated. Similar to the synergistic mechanism in binuclear homogeneous catalysts, from both experimental and theoretical results, it is proved that electrons would redistribute between the two oxo‐bridged paired Pt sites after hydrogen adsorption on one site, which enables the other Pt site to have high CO oxidation activity at mild‐temperature. The dynamic electronic interaction between neighboring Pt sites is found to be distance dependent. These new SACs with abundant Pt‐O‐Pt paired structures can improve the efficiency of CO chemical purification. This work investigates the synthesis and CO chemical purification applications of densely populated single‐atom catalysts. Because of electron bridge interaction and cooperative activation of two Pt1 sites, this CO chemical purification technology has a record‐low cost and high CO purity. Furthermore, the Pt1 site is not the active site of the CO oxidation in Pt1/TiO2, but the Pt1‐O‐Pt1 site is.