The adsorption properties of CO2 and O-2 on SiC nanosheets were fully investigated using the density functional theory method. CO2 molecule always acted as an acceptor regardless the existence of pre-adsorbed O-2 on SiC nanosheet surface and attracted electrons from its surface. Theoretical results implied that SiC nanosheet was a good adsorbent of CO2 molecule. Pre-adsorbed O-2 attracted electrons from SiC nanosheet and resulted in less electrons transferred to CO2 molecule from SiC nanosheet. (C) 2015 Elsevier B.V. All rights reserved.