Precise Synthesis at the Atomic Scale

Precise synthesis at the atomic scale is a highly desirable and controllable route for the preparation of heterogeneous catalysts with the desired structure and properties,which promotes the rational design of highly efficient catalysts and facilitates the understanding of structure-properties relationship.The precise construction of the active sites of the catalysts provides important opportunities for atomic insight into the correlation between structure and catalytic performance.In this review,the atomic-level tuning strategies for the precise synthesis of heterogeneous catalysts are summarized with the emphasis on the precise control of the structure of active sites,including single atom sites,dual atom sites and complex active sites.Furthermore,we illustrate the crucial role of atomic-level regulation of structure in determining the catalytic performance by providing typical catalysis examples in different reactions.In the end,some perspectives on the further development of precise synthesis of catalysts at the atomic level are presented.

Metal-organic frameworks-derived nitrogen-doped carbon supported nanostructured PtNi catalyst for enhanced hydrosilylation of 1-octene

Here,we successfully developed nano structured PtNi particles supported on n itroge rrdoped carbon(NC),which were obtai ned by carbon izati on of metal-organic frameworks under different temperatures,forming the nano-PtNi/NC-600,nano-PtNi/NC-800,nano-PtNi/NC-900 and nano-PtNi/NC-1000 catalysts.For hydrosilylation of 1-octene,we found that the nano-PtNi/NC-1000 catalyst exhibits higher activity for anti-Markovnikov hydrosilylation of 1-octene than those of nano-PtNi/NC-600,nano-PtNi/NC-800,nano-PtNi/NC-900 catalysts.Experiments have verified that benefiting from obvious charge transfer from nano-PtNi particles to NC support carbonized at 1,000℃,the nano-PtNi/NC-1000 catalyst achieved almost complete conversion and produce exclusive adduct for anti-Markovnikov hydrosilylation of 1-octene.Importantly,the nano-PtNi/NC-1000 catalyst exhibited good reusability for the hydrosilylation reaction.This work provides a new path to optimize electronic structure of catalysts by support modification to enhance electron transfer between metal active species and supports for highly catalytic performance.

Pd single-atom monolithic catalyst: Functional 3D structure and unique chemical selectivity in hydrogenation reaction

Regulating the selectivity of catalysts in selective hydrogenation reactions at the atomic level is highly desirable but remains a grand challenge. Here we report a simple and practical strategy to synthesize a monolithic single-atom catalyst(SAC) with isolated Pd atoms supported on bulk nitrogen-doped carbon foams(Pd-SAs/CNF). Moreover, we demonstrate that the single-atom Pd sites with unique electronic structure endow Pd-SAs/CNF with an isolated site effect, leading to excellent activity and selectivity in 4-nitrophenylacetylene semi-hydrogenation reaction. In addition, benefiting from the great integrity and excellent mechanical strength, monolithic Pd-SAs/CNF catalyst is easy to separate from the reaction system for conducting the subsequent recycling. The cyclic test demonstrates the excellent reusability and stability of monolithic Pd-SAs/CNF catalyst.The discovery of isolated site effect provides a new approach to design highly selective catalysts. And the development of monolithic SACs provides new opportunities to advance the practical applications of single-atom catalysts.