The ultrasmall Ni metallic nanoparticles constructed by SOMC for CO2 hydrogenation

Ni-based heterogeneous catalysts have attracted attention because of their relatively low cost and intriguing structure-sensitive effects. However, the study into size effect below 2 nm is still lacking since the preparation of sub-2 nm metallic Ni is extremely challenging. Via surface organometallic chemistry (SOMC) method, we have successfully synthesized a series of evenly size-distributed Ni nanoparticles (Ni-NPs) on Al2O3 with the average size from 1.4 nm to 4.3 nm. By conducting ex situ as well as in situ x-ray absorption spectroscopy experiments, we can obtain insight into how the support can stabilize the small size Ni-NPs, and identify the speciation of these Ni catalysts especially under working state. With the combination of in situ XAS with other spectroscopic, microscopic and physico-chemical characterization techniques, as well as the evaluation results on these materials, we will have promising approach to the understanding of the Ni-NPs size effect in CO2 hydrogenation.