Reagentless preparation of shape memory cellulose nanofibril aerogels decorated with Pd nanoparticles and their application in dye discoloration

An environmentally benign method was reported for synthesizing highly porous cellulose nanofibril (CNF) aerogels decorated with palladium nanoparticles (PdNPs). Small PdNPs (< 25 nm in diameter) were successfully immobilized and reduced on the CNF surface by simply mixing the TEMPO-oxidized CNF dispersion with the palladium precursor solution and heating the aqueous mixture to 80 degrees C for 2 h. The resulting CNF-PdNPs hybrids could self-assemble into water-activated shape memory aerogels by freeze-drying the nanohybrid suspension. The as-prepared hybrid aerogels were successfully applied to the catalytic discoloration of aqueous cationic and anionic dye solutions in batch and dynamic column processes. The CNF-PdNP aerogels exhibited very high catalytic activity and could be conveniently separated from the products and reused with 91-99% discoloration efficiency for multiple cycles. No obvious deterioration of the material properties and structural integrity was observed during testing, hence demonstrating great potential for practical environmental remediation and catalytic applications.