Activity promotion of Rh_(1)Ca_(x)/Al_(2)O_(3) single-atom catalyst in 1-octene hydroformylation:a volcano curve exists between Ca adding ratio and catalytic activity

Single-atom catalysts(SACs)are considered the best candidates for olefin hydroformylation due to their combined advantages of homogeneous and heterogeneous catalysts.Unlike conventional organo-phosphine modification,Rh SAC is modified by introducing Ca,resulting in a significant increase in activity(maximum~5.7-fold)and stability.Furthermore,a volcano curve between Ca addition ratio and catalytic activity is found.Introducing Ca significantly increases activity by decreasing the energy barrier,but excessive Ca decreases activity due to hindering substrate adsorption and reaction.

Tandem hydroformylation/hydrogenation of olefins to alcohols using atomically dispersed bifunctional catalysts

Tandem hydroformylation/hydrogenation of olefins to alcohols is an appealing and challenging route that has received continuous interest. Herein, we report a bifunctional atomically dispersed Rh and Co catalyst(Rh Co/Al_(2)O_(3)-10) prepared by a simple ball milling method that displays superior synergistic catalytic performance(>95% olefins conversion and >80% alcohols selectivity) and broad substrate scope for tandem hydroformylation/hydrogenation reaction, outperforming Rh/Al_(2)O_(3), Co/Al_(2)O_(3),and their physically mixed counterparts. In situ CO-DRIFTS, XPS, and kinetic experiments demonstrate that the electron interaction between Rh and Co atoms effectively lowers the apparent activation energy, thus promoting the tandem hydroformylation/hydrogenation reaction. This work not only presents a novel tandem hydroformylation/hydrogenation reaction system for converting olefins to alcohol but also throws light on the rational design of versatile bifunctional catalysts for ondemand synergistic catalysis.