Developing metal-free catalysts for CO oxidation has been a key scientific issue in solving the growing environmental problems caused by CO emission.In this work,the potential of the silicon carbide(SiC)monolayer as a metal-free catalyst for CO oxidation was systematically explored by means of density functional theory(DFT)computations.Our results revealed that CO oxidation reaction can easily proceed on SiC nanosheet,and a three-step mechanism was proposed:(1)the coadsorption of CO and O2 molecules,followed by(2)the formation of the first CO2 molecule,and(3)the recovery of catalyst by a second CO molecule.The last step is the rate-determining one of the whole catalytic reaction with the highest barrier of 0.65 eV.Remarkably,larger curvature is found to have a negative effect on the catalytic performance of SiC nanosheet for CO oxidation.Therefore,our results suggested that flat SiC monolayer is a promising metal-free catalyst for CO oxidation.