Porous Cu-BTC Metal–Organic Frameworks Anchored on Dialdehyde Wood Sponge as Material for CO₂ Capture and Separation

Wood-based substrates decorated with metal–organic frameworks (MOFs) postcarboxylation have garnered significant attention for CO 2 capture. However, the practical applicability of composites synthesized via this method is constrained by modification difficulty, low binding strength, and environmentally unfriendly processes. In this work, we introduce an innovative approach that involves the oxidation of hydroxyl groups on wood cellulose C2 and C3 to aldehyde groups, producing a dialdehyde wood sponge (DWS). Subsequently, Cu-BTC MOFs (HKUST-1) were grown in situ in the 3D framework of the wood sponge through chelation. This strategy enhances the affinity between the MOFs and the wood-derived skeleton, significantly increasing the micropore surface area to 402 m 2 /g, with the micropores primarily concentrated at 0.71 nm. Benefiting from its high MOF load and abundant microporous structure, HKUST-1/DWS achieved a CO 2 capture capacity of 2.34 mmol/g (273 K, 1 bar), remarkably surpassing that of HKUST-1/TWS (carboxylated wood sponge by 2,2,6,6-tetramethylpiperidinooxy), which exhibited a capacity of 1.59 mmol/g. Additionally, the synthesized solid adsorbent demonstrated high CO 2 /N 2 adsorption selectivity (47.95), indicating the potential for efficient CO 2 separation. This method of constructing MOF/wood-based CO 2 sorbents enables chemical modification and facilitates efficient and sustainable carbon dioxide capture.