Abstract: Porous solid scaffolds play key roles in preventing nanocatalysts from agglomeration, greatly maintaining the catalytic efficiency and stability of nanocatalysts. However, facile preparation of robust scaffolds with high mass transfer efficiency for loading nanocatalysts remains a major challenge. Here, we fabricate a wood-inspired shape-memory chitosan scaffold for loading Au nanoparticles to reduce 4-nitrophenol via a simple “freeze-casting and dip-adsorption” approach. The obtained catalytic scaffold highly resembles the unidirectional microchannel structure of natural wood, resulting in robust mechanical properties and outstanding water absorption capacity. Additionally, Au nanoparticles can be firmly and uniformly anchored on the inner surface of these microchannels via electrostatic interaction, forming numerous microreactors. This catalytic system exhibits a high 4-nitrophenol conversion rate of 99% in 5 s and impressive catalytic stability even after continuously treating with more than 3 L of highly concentrated 4-nitrophenol solution(1 mmol/L). Therefore, the wood-like catalytic system presented here demonstrates the potential to be applied in the field of water treatment and environmental protection.

Key words: Wood-like structure, Freeze casting, Catalytic scaffold, Shape-memory, Mass transfer efficiency