Understanding Ligand‐Directed Heterogeneous Catalysis: When the Dynamically Changing Nature of the Ligand Layer Controls the Hydrogenation Selectivity

Abstract We present a mechanistic study on the formation and dynamic changes of ligand‐based heterogeneous Pd catalyst for chemoselective hydrogenation α,β‐unsaturated aldehyde acrolein. Deposition allyl cyanide as precursor ligand layer renders highly active close to 100 % selective toward propenol by promoting acrolein adsorption in desired configuration via C=O end. Employing combination real‐space microscopic in‐operando spectroscopic surface‐sensitive techniques, we show that an ordered is formed under operational conditions, consisting stable N‐butylimine species. In competing process, unstable amine species evolve surface, which desorb course reaction. Obtained atomistic‐level insights into evolution conditions provide important input required controlling chemoselectivity purposeful surface functionalization.