Molecular Engineering of Co-doped Mesoporous Polymer-Derived Carbon toward Precise N,O Configurations for Boosting Pd-Catalyzed Selective Alkynol Hydrogenation.

Abstract

Carbon-supported Pd catalysts are pivotal in alkynol hydrogenation for fine chemicals and pharmaceuticals. Heteroatom doping and porous structures of supports can modulate the metal electronic structure and improve mass transfer, respectively, thereby influencing catalytic activity. However, precise control over doping configurations and porous support construction remains challenging. Herein, we present molecular engineering based on the three-component polymerization of ascorbic acid, ethylenediamine, and glyoxal to design mesoporous co-doped carbon with adjustable N and O composition. The strategy enables a high degree of control over mesoporous structures and phenolic and pyridinic N configurations, thereby facilitating the anchoring of Pd nanoparticles. Density functional theory calculations reveal that the interplay between lone-pair electrons of phenolic O and pyridinic N induces local strain and charge polarization, activating Pd clusters and lowering the hydrogenation barrier. The optimized supported Pd catalyst delivers an exceptional turnover frequency of 47 890 h^-1 and 95% selectivity in the semi-hydrogenation of 2-methyl-3-butyn-2-ol.