Boosting Activity and Stability of Metal Single-Atom Catalysts via Regulation of Coordination Number and Local Composition

Controlling the chemical environments of the active metal atom including both coordination number (CN) and local composition (LC) is vital to achieve active and stable single-atom catalysts (SACs), but remains challenging. Here we synthesized a series of supported Pt-1 SACs by depositing Pt atoms onto the pretuned anchoring sites on nitrogen-doped carbon using atomic layer deposition. In hydrogenation of para-chloronitrobenzene, the Pt-1 SAC with a higher CN about four but less pyridinic nitrogen (N-pyri) content exhibits a remarkably high activity along with superior recyclability compared to those with lower CNs and more N-pyri. Theoretical calculations reveal that the four-coordinated Pt-1 atoms with about 1 eV lower formation energy are more resistant to agglomerations than the three-coordinated ones. Composition-wise decrease of the Pt-N-pyri bond upshifts gradually the Pt-5d center, and minimal one Pt-N-pyri bond features a high-lying Pt-5d state that largely facilitates H-2 dissociation, boosting hydrogenation activity remarkably.

Automated summary

Controlling the chemical environments of active metal atoms is crucial for achieving active and stable single-atom catalysts. Supported Pt-1 SACs with higher coordination number and less pyridinic nitrogen content show superior catalytic activity and recyclability in hydrogenation reactions. Theoretical calculations reveal that the composition-wise decrease of Pt-N-pyri bond plays a key role in enhancing hydrogenation activity.