Highly Nanoporous Multi-Functional Wood Aerogels

Aerogels, featuring low density (< 0.5 g/cm³), high porosity (>90%), and high specific surface area (SSA) (> 100 m²/g), show vital roles in various areas such as super thermal insulation, separation, catalyst, etc. Cellulose stands out ascribing to the abundant and fossil-free resources and the favorable mechanical properties. The mainstream fabrications of cellulose aerogels are from a bottom-up approach, the energy consumption and hierarchical porous structure reconstruction are challenging for cost-effective and scalable production. A top-down approach directly from wood was reported recently through delignification and sometimes followed by hemicellulose extraction. However, the SSA is low and meso/micro pores are limited. Here, we propose an approach to fabricate hierarchical wood aerogel through cell wall partial dissolution and regeneration in the lumen space. The aerogel combines high SSA (up to 250 m²/g) with good mechanical strength (1.2 MPa) and abundant of meso/micro pores. The aerogel could be further modified for advanced applications such as thermal insulation, energy harvesting, etc.