Tube-in-tube carbon nanostructures (TTCNTs) have been successfully constructed on liquid membranes via a hydrogen-bonding linkage of small graphene sheets around normal carbon nanotubes (CNTs). The effects of solvent (water, tetrahydrofuran (THF), ethanol, n-hexane and N,N-dimethylformamide (DMF)) and membrane thickness on the assembling process were investigated. Results show that the formed cavity of TTCNTs becomes large with the increase of viscosity of solvent and pressure. The formed liquid membrane on CNTs surface plays a key role in this process, and it can be controlled by adjusting the membrane thickness and solvent nature. Moreover, TTCNTs show excellent catalytic reduction NO ability at low temperatures. (C) 2009 Elsevier B.V. All rights reserved.