In-situ XAS study on zeolite-encapsulated sub-nanometer Rh clusters for regioselective propylene hydroformylation

In this proposal, we have prepared MFI zeolite-confined Rh clusters that exhibit excellent regioselectivity (n-butanal/i-butanal > 400) and enhanced conversion for propylene hydroformylation, one of the world’s largest homogenous reactions. The superior regioselectivity is the combined result of zeolite confinement, promoters, and the chemical states of Rh sites. During mechanism studies, we found that the pretreatment with specific reactants (CO, H2, or propylene) can significantly affect the catalytic behavior, indicating that the electronic structures of Rh sites play a significant role during hydroformylation. Therefore, by tracking the in-situ structural evolution (including the coordination environment and chemical states by EXAFS and XANES), we seek to unravel the individual contribution of reactants on the electronic property and catalytic performance of Rh clusters.