A novel kind of ZnO based N-doped reduced graphene oxide (N-rGO-ZnO) porous nanomaterial was successfully synthesized by a two-step method. CO2 and N-2 adsorption-desorption measurements and pore size analysis of N-doped reduced graphene oxide (N-rGO) and N-rGO-ZnO have been investigated and compared. What's more, the adsorption isotherms of N-rGO-ZnO material were measured at different temperatures, and it exhibited a large CO2 adsorption ability of 3.55 mmol/g at 298K and 1 atm. The impressive CO2 adsorption selectivity over N-2 has also been calculated and determined to be 35.84 by a slope method, which indicates the potential application to separate CO2 from flue gases. (C) 2015 Elsevier B.V. All rights reserved.