Pd Nanoparticles Immobilized on Bacterial Cellulose: A Sustainable Catalyst for Selective Hydrogenation of Vanillin

Catalyst supports critically affect the efficiency and selectivity of supported metal catalysts. In this investigation, bacterial cellulose (BC) produced through bacterial fermentation was used as a catalyst support, with Pd 2+ loaded on BC and then reduced to prepare a supported Pd catalyst (Pd/BC). Owing to its nanofibrous structure and abundant hydroxyl groups exposed on the surface of BC, BC adsorbed more Pd 2+ via electrostatic interaction and promoted the dispersion of Pd particles, resulting in their smaller particle size. The high crystallinity index of BC endowed the catalyst with high thermal stability, enabling its application in the catalytic hydrogenation of vanillin (a lignin-derived platform chemical) under mild reaction conditions. Strong hydrogen bonding interaction between C6-OH on BC surface and the aldehyde group of vanillin facilitated the hydrogenation rate of vanillin. The hydrogenation of vanillin over the 3 wt% Pd/BC catalyst at 60 °C under 1.5 MPa H 2 for 2 h resulted in 98.45% vanillin conversion and 97.85% yield of vanillyl alcohol, with high recycling stability, and good catalytic universality, effectively catalyzing the hydrogenation of different lignin-derived aldehydes. This study paves the way for the application of cellulose with polyhydroxy groups in catalysis.