Recently, the research group of Prof. Zeng has provided a quantitative profile for exploring metal-support interactions by considering the highest occupied state in single-atom catalysts. This work has been published on Angewandte Chemie International Edition with the title of “The Highest Occupied State of Rh Single Atoms Controls the Catalytic Properties towards Ammonia Borane Hydrolysis” [Angew. Chem. Int. Ed. 2017, 56, 4712-4718]. Doctor Liangbing Wang and Master Hongliang Li contributed equally.

Rh₁/VO₂ single-atom catalysts and their catalytic performance

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. However, it remains challenging to quantitatively understand the nature of metal–support interactions owing to the lack of detailed knowledge of reaction processes in hydrolysis reactions and active sites at the atomic level. To solve the aforementioned problems, state-of-the-art single-atom catalysts have been proposed as an ideal platform to investigate metal–support interactions because interference from the size, shape, and orientation of the metal particles at the metal–support interface can be readily excluded.

The researchers constructed a single-atom catalyst consisted of isolated Rh atoms uniformly dispersed on the surface of VO₂ nanorods (denoted as Rh₁ /VO₂). During NH₃BH₃ hydrolysis, changes in the activation energy were induced by phase transitions of the substrate. Further experimental analysis and DFT calculations indicate that the catalytic performance directly correlates with the highest occupied state of the individual Rh atoms, which in turn depends on the band structure of the substrate. Based on the aforementioned reaction mechanism, other metal catalysts, even with non-noble metals, that exhibit significant catalytic activity towards NH₃BH₃ hydrolysis were rationally designed by adjusting their highest occupied states. This work provides a guideline for the rational design of efficient and inexpensive catalysts towards hydrogen generation by controlling the band structures of the catalysts.

This work was supported by MOST of China, and the National Natural Science Foundation of China.

http://onlinelibrary.wiley.com/doi/10.1002/anie.201701089/full.