Understanding support effects on Rh2P catalyzed styrene hydroformylation by combining characterizations and kinetics

Styrene hydroformylation over Rh2P loaded on different oxides was compared to investigate support effects on catalytic performance. The electron density of Rh was probed by CO-DRIFTS, and the acid-base properties of the catalysts were detected by NH3– and CO2-TPD. Rh2P had higher electron density when loaded on basic supports, and n-type semiconductor showed additional electron donation effects compared to isolators. A kinetics model was established to identify hydrogen addition as the rate-determining step, and the changes in rate constant and adsorption equilibrium with different supports were compared. Electron donation from the supports was found to promote the activity of Rh2P via weakening styrene and aldehyde adsorption and facilitating hydrogen addition. The advantage of using CeO2 (i.e., basic oxide with n-type semiconductivity) as the support was suggested.