Supported Rhodium Catalysts for Ammonia–Borane Hydrolysis: Dependence of the Catalytic Activity on the Highest Occupied State of the Single Rhodium Atoms

• Published in: Angewandte Chemie International Edition 2017-04, Vol.56 (17), p.4712-4718
• Main Authors: Wang, Liangbing, Li, Hongliang, Zhang, Wenbo, Zhao, Xiao, Qiu, Jianxiang, Li, Aowen, Zheng, Xusheng, Hu, Zhenpeng, Si, Rui, Zeng, Jie
• Format: Article
• Language: English
• Subjects: Ammonia; Atomic structure; Atoms & subatomic particles; Band structure of solids; Catalysts; Catalytic activity; Dependence; Heavy metals; Hydrolysis; Metals; metal–support interactions; Nanorods; Noble metals; Phase transitions; Rhodium; Shells; Single atom catalysts; Substrates; vanadium dioxide
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201701089

Supported metal nanocrystals have exhibited remarkable catalytic performance in hydrogen generation reactions, which is influenced and even determined by their supports. Accordingly, it is of fundamental importance to determine the direct relationship between catalytic performance and metal–support interactions. Herein, we provide a quantitative profile for exploring metal–support interactions by considering the highest occupied state in single‐atom catalysts. The catalyst studied consisted of isolated Rh atoms dispersed on the surface of VO2 nanorods. It was observed that the activation energy of ammonia–borane hydrolysis changed when the substrate underwent a phase transition. Mechanistic studies indicate that the catalytic performance depended directly on the highest occupied state of the single Rh atoms, which was determined by the band structure of the substrates. Other metal catalysts, even with non‐noble metals, that exhibited significant catalytic activity towards NH3BH3 hydrolysis were rationally designed by adjusting their highest occupied states. Phase‐dependent: When a catalyst consisting of isolated rhodium atoms dispersed on the surface of VO2 nanorods was employed for ammonia–borane hydrolysis, the activation energy changed when the substrate underwent a phase transition. Mechanistic studies indicate that the catalytic performance depends directly on the highest occupied state of the single Rh atoms, which is determined by the band structure of the substrate.