In this paper, we perform three typical oxidation treatments, such as O-3, HNO3 and H2O2, to modify the surface structure of the novel three dimensional carbon nanosheets (3D CNSs). The different treatment generates kinds of oxygenated functional groups on the surface of support. One of them, the CNSs treated by ozone produces the greatest amount of carboxyl groups and keeps the original morphology, which can be used as the excellent support for the electrochemical oxidation of methanol in acidic medium. Through various characterizations, it is discovered that the PtCo/CNSs-1 shows the excellent lamellar structure, good crystallinity, abundant pore structure and large interlayer spacing, which provide ultrahigh specific surface area, superb electron and ionic conductivity. Furthermore, the superfine PtCo alloy nanoparticles evenly deposits on the 3D CNSs, which reveals superior electrocatalytic performance. More importantly, the capacity of anti-poisoning of which is enhanced obviously. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.