Pd Supported on Surface Sulfur‐Doped Mesoporous Monolithic Carbon to Boost Semihydrogenation of Alkynols

Abstract Pd‐catalyzed semihydrogenation of alkynols to enols is a pivotal industrial process for synthesizing fine chemicals like fragrances and vitamins. The selection of carbon‐based supports is crucial due to their advantages in good chemical and thermal stability, tunable surface properties, and facile metal recovery via combustion. Herein, we constructed the wood‐based monolithic carbon support with a sulfur‐doped mesoporous carbon layer to anchor high‐dispersed Pd nanoparticles. This mesoporous carbon layer was fabricated via co‐polymerization of 2‐thiophenemethanol and tetraethoxysilane monomers formed by decomposition of the tetrakis(2‐thiophenemethoxy)silane on wood substrates, followed by pyrolysis, and removal of silica. The resultant Pd/C catalyst exhibited high catalytic activity (4323 mol mol Pd −1 h −1 ) and selectivity (93% at 99% conversion) under mild conditions (298 K, 2 bar H 2 ) in 2‐methyl‐3‐butyn‐2‐ol (MBY) semihydrogenation. The thiophene‐like sulfur and mesoporous framework synergistically promoted Pd dispersion, thereby boosting catalytic activity. Meanwhile, the electron‐rich Pd 0 sites, which originated from electron donation of thiophene‐like sulfur species, significantly enhanced catalytic selectivity. Additionally, the sulfur‐modified monolithic catalyst presented good stability over five cycles and facile separation from the solution. It also displayed broad applicability in diverse alkynol semihydrogenation reactions, demonstrating high potential for liquid‐phase catalytic applications.