Gaseous thermal conductivity takes up a great proportion of the thermal conductivity of aerogels. In this work, we present a new strategy to restrain the gaseous thermal conductivity, using 3-dimension nano porous aerogels from 2-dimension sheets. Experimental results show that the N-doped graphene aerogels, typical nanoporous aerogels from 2-dimension sheets, exhibit very low gaseous thermal conductivity (12.58 mW m(-1) K-1 at room temperature) at extremely low bulk density (0.0320 g cm(-3)), suggesting that the nanoporous aerogels from 2-dimension sheets can restrain the gaseous thermal conductivity more efficiently than that from 2-dimension pearls. This finding may significantly contribute to the next generation of thermal insulation materials with lower thermal conductivity and much lower density. (C) 2017 Elsevier Ltd. All rights reserved.