Ionic liquid-assisted growth of Cu 3 (BTC) 2 nanocrystals on graphene oxide sheets: Towards both high capacity and high rate for CO 2 adsorption

•Ionic liquid-assisted growth of GO-IL/MOF composite method was proposed.•The superimposed hierarchical structure of GO-IL/MOF composite was obtained.•The composite showed a high CO2 adsorption capability of 5.62mmol/g.•The composite showed a fast CO2 kinetic separation performance.•The composite presented a good cyclic adsorption/desorption stability.