▎ 摘　　要

Synthesis of large sized high-quality bi- and trilayer graphene grains in chemical vapor deposition on a copper surface is still a challenge due to the self-limiting growth. In this work, we demonstrated a facile way to break the self-limiting growth on copper by replacing fresh copper surface with oxidized copper surface, in which copper nanoparticles induced by oxidation play a vital role in the graphene nucleation process. As a result, a high yield of bi-and trilayer graphene grains with average size of similar to 80 mu m and similar to 50 mu m in diameter can be easily achieved. The high quality of grains has been identified by Raman, selected area electron diffraction and electronic measurement. Moreover, the yield and distribution of bi-and trilayer grains can be tuned by the morphologies of oxidized copper substrates, namely, the distribution of copper nanoparticles, supporting the strong positive relationship between copper nanoparticles and graphene nuclei (bi-and trilayer grains).