PT Journal AU Schauermann, S TI Partial Hydrogenation of Unsaturated Carbonyl Compounds: Towards Ligand-Directed Heterogeneous Catalysis SO The journal of physical chemistry letters PY 2018 BP 5555 EP 5566 VL 9 IS 18 PU Universitätsbibliothek DI 10.1021/acs.jpclett.8b01782 WP https://macau.uni-kiel.de/receive/publ_mods_00002206 LA en DE acrolein partial hydrogenation; Pd(111); Pd nanoparticles SN 1948-7185 AB In this perspective, we report on the recent progress in atomistic-level understanding of selective partial hydrogenation of α,β-unsaturated carbonyl compounds, particularly acrolein, towards unsaturated alcohols over model single crystalline and nanostructured Pd catalysts. This reaction was observed to proceed with nearly 100% selectivity over Pd(111) but not over supported Pd nanoparticles. The origin of the high selectivity was related to formation of a dense overlayer of oxopropyl surface species occurring at the early reaction stages via partial hydrogenation of the C=C bond in acrolein with only one H atom. This oxopropyl overlayer strongly modifies the adsorption and reactive properties of Pd(111) turning it 100% selective towards C=O bond hydrogenation. The underlying reaction mechanism represents a particular case of ligand-directed heterogeneous catalysis, in which the surface adsorbates do not directly participate in the catalytic process as the reaction intermediates but strongly affect the elementary reaction steps via specific adsorbate-adsorbate interactions. PI Kiel ER