Spacer-Assisted Amine-Coiled Carbon Nanotubes for CO2 Capture

Architecture of a DNA-wrapped carbon nanotube (CNT) inspires rational design of a polymer-wrapped CNT effective for CO 2 capture. Polyethyleneimine (PEI) selected as a spiral wrapper of CNT is modified by insertion of spacer molecules loaded with amino groups such as siloxanes and purine to enhance the CO 2 capture performance. A porous adsorbent made by packing these functional nanowires (e.g., PEI–purine–CNT) reveals CO 2 uptake as large as 3.875 mmol/g. Adsorbent materials from this biomolecule-inspired design drop the adsorption heat to 29.00 kJ/mol if secondary and tertiary amines are adopted, besides the primary one, a value that is one-third of the absorption heat of an industrially deployed, liquid absorbent of CO 2 . The corresponding adsorption and desorption kinetics agree with an Avrami model, indicating that both processes involve multiple sorption pathways. Furthermore, PEI–purine–CNT maintains its adsorption capacity after 50 adsorption–desorption cycles, implying a great potential for carbon capture from smokestacks and air in a stable and cyclic manner.