Strategy for Synthesizing Porous Cellulose Nanocrystal Supported Metal Nanocatalysts

This paper describes a novel platform to prepare small and uniformly distributed metal nanoparticles (MNPs) on cellulose nanocrystals for use as high performance sustainable nanocatalysts. The model platinum or palladium NPs (1–2 nm in size) were immobilized and chemically reduced onto melamine-formaldehyde (MF) coated cellulose nanocrystals (MFCNCs). The MF coating was critical for the uniform generation and size-control of MNPs. The contribution of MF resin to optimal MNP synthesis includes: (1) increased surface area with its spongelike structure, (2) enhanced affinity to metals through chelation with nitrogen functionalities, and (3) effective MNP size control due to the mesoporous structure. The MNP/MFCNC system significantly improved catalytic activity as demonstrated by the reduction of 4-nitrophenol with Pd/MFCNCs with a turnover frequency of 3168 h –1 . Our synthesis does not require any complicated apparatus or harsh reaction conditions. The proposed strategy is well-suited for the synthesis of a wide range of metal nanocatalysts characterized by a particle size of 1 to 2 nm and superior catalytic activity.