Biogenic Support for Pd Nanoparticles: A Dip-Catalyst for Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

Biogenic resources are increasingly recognized as attractive raw materials for catalytic applications, particularly in the context of sustainable chemistry. In this study, sponge gourd (SG) (Luffa cylindrica) was employed as a novel biogenic support for palladium nanoparticles (Pd@SG) in dip-catalysis system for the chemoselective hydrogenation of cinnamaldehyde (CAL). Unlike conventional oxide or carbon supports, the highly porous and functionalized cellulose network of sponge gourd provided strong immobilization sites for Pd nanoparticles (2–4 nm), resulting in enhanced stability and recyclability. Pd@SG was extensively characterized by SEM, EDS, XRD, FTIR, XPS, and TEM. Catalytic testing revealed > 99% conversion of CAL with > 99% chemoselectivity toward hydrocinnamaldehyde (HCAL) under 30 bar H₂ at 80 °C. The dip-catalyst configuration enabled facile insertion, removal, and reuse of the catalyst, which retained high activity and selectivity for up to five consecutive cycles.