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Atomic cluster-supported (left) Au atom catalyzes the oxidation of CO (right) Pt atom at room temperature activates conversion of CH4
Precious metals exhibit excellent catalytic reactivity. They are distributed as a single atom on the surface of the support. The resulting monoatomic catalysts are capable of maximizing the efficiency of the use of precious metals and provide new ways to control the activity and selectivity of catalytic reactions. It is of great significance for the rational design of catalytic reactions to study the elementary steps in the catalytic reaction of noble metals and to understand the mechanism and nature of the precious metals. However, it is very technically challenging to study the catalytic process at the single atom resolution level.
Recently, under the support of the National Natural Science Foundation of China, the Ministry of Science and Technology, and the Chinese Academy of Sciences, researchers in the Laboratory of Molecular Dynamics and Steady State Structure at the Institute of Chemistry, Chinese Academy of Sciences, have attempted to load a single precious metal atom onto a cluster formed by a finite number of atoms. High-resolution mass spectrometry technology has been used to measure the reactivity of cluster monoatomic catalysts at a single atomic weight resolution level and has made a series of research advances.
Oxide is an important type of catalyst support material. The researchers have systematically studied the structure and properties of oxide support clusters and have a deep understanding of active oxygen bonding and its reactivity control (Acc. Chem. Res. 2012 , 45, 382; J. Am. Chem. Soc. 2013, 135, 2991; Angew. Chem. Int. Ed. 2013, 52, 2444). The researchers found that by loading a single gold atom onto a cluster of inexpensive metal oxides, gold can efficiently trap carbon monoxide molecules and transfer them to the cluster support for oxidation. Gold is effectively stored in the reaction by polarity inversion of the oxidation state. The released electrons thus greatly increase the reactivity of the system (J. Am. Chem. Soc. 2014, 136, 3617; J. Phys. Chem. Lett. 2014, 5, 1585).
Further, in the introduction of reactive oxygen species in the cluster system, combined with isotope substitution experiments, the researchers clearly observed the catalytic reactivity of a single gold atom (J. Am. Chem. Soc. 2014, 136, 14307). Mechanism studies have shown that gold The atoms, in turn, bond with oxygen and metal to release and store electrons, which in turn drive the cycling of the catalytic reaction. The researchers also found that the single platinum atom supported by the cluster was able to effectively activate particularly stable methane molecules (Angew. Chem. Int. Ed. 2014, 53, 9482), which was converted to Formaldehyde at room temperature. These works provide new methods and new ideas for understanding the mechanism of mono-catalyzed noble metals.
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