化学
化学工程
吸附
无机化学
密度泛函理论
X射线光电子能谱
作者
Yongseon Kim,Greg Collinge,Mal Soon Lee,Konstantin Khivantsev,Sung June Cho,Vassiliki Alexandra Glezakou,Roger Rousseau,János Szanyi,Ja Hun Kwak
标识
DOI:10.1002/anie.202105750
摘要
The analogy between single-atom catalysts (SACs) and molecular catalysts predicts that the specific catalytic activity of these systems is constant. We provide evidence that this prediction is not necessarily true. As a case in point, we show that the specific activity over ceria-supported single Pd atoms linearly increases with metal atom density, originating from the cumulative enhancement of CeO2 reducibility. The long-range electrostatic footprints (≈1.5 nm) around each Pd site overlap with each other as surface Pd density increases, resulting in an observed deviation from constant specific activity. These cooperative effects exhaust previously active O atoms above a certain Pd density, leading to their permanent removal and a consequent drop in reaction rate. The findings of our combined experimental and computational study show that the specific catalytic activity of reducible oxide-supported single-atom catalysts can be tuned by varying the surface density of single metal atoms.
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