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.