Photoinduction of palladium single atoms supported on defect-containing γ-AlOOH nanoleaf for efficient trans-stilbene epoxidation

Exploring the interaction between metal and support is of great importance in enhancing the catalytic performance and deepening the mechanistic understanding of single atom catalysis. Here we describe a photoinduction method to construct atomically dispersed palladium atoms supported over defect-containing boehmite (γ-AlOOH) nanoleaf with a palladium loading of 0.32 wt%. The existence of singly dispersed palladium atoms is confirmed by spherical aberration correction electron microscopy, extended X-ray absorption fine structure measurement, and CO-absorbed diffuse reflectance infrared Fourier transform spectroscopy. This catalyst shows excellent catalytic efficiency in trans -stilbene epoxidation to yield trans -stilbene oxide (TOF: 416 h −1 ; conversion: 84 %; selectivity: 99 %), along with excellent recyclability and scalability. In addition, various aromatic olefins were successfully transformed into the corresponding epoxides with high selectivity and excellent yield. DFT study further reveals that the high catalytic activity originates from under-coordinated single palladium atoms in the defect-containing γ-AlOOH in a unique coordination environment. This lays the foundation for the facile creation of single atom catalysts and sheds light on the possibility for scale-up production.