Carbon Decorated Pd Species within Zeolite for Selective Furfural Hydrogenation.

Selective hydrogenation of biomass-derived furfural to furfuryl alcohol is fundamentally challenged by the dual adsorption of its reactive furan ring and carbonyl group on Pd catalysts, which drives nonselective pathways. To modulate the adsorption mode of furfural, we rationally incorporate carbon species onto Pd subnanoclusters encapsulated in a siliceous zeolite (Pd-C@S-1), achieving 98% selectivity for furfuryl alcohol at full furfural conversion, vastly outperforming the carbon-free Pd@S-1 (11.6% selectivity). Comprehensive characterizations and theoretical calculations reveal that the enhanced catalytic efficiency of Pd-C@S-1 arises from carbon-induced modifications to the electronic and steric properties of Pd. The resulting Pd-C species promote a vertical adsorption orientation of furfural via the carbonyl group, sterically hindering interactions between the furan ring and Pd active sites, thus leading to high selectivity for furfuryl alcohol. This work demonstrates that the modification of Pd with carbon species can alter the substrate adsorption configurations, enabling precise control over reaction pathways and offering a facile strategy for designing selective catalysts in biomass conversion.