▎ 摘　　要

To uncover the distinction in the electronic density of states (DOS) near Fermi level at the graphene and metal, we compare the standard rate constant k(0) values for quinone species at graphene and gold nanoelectrodes, which might be affected by the electronic DOS near Fermi level. The experimental result indicates that the k(0) value obtained at the individual graphene flake of nanometer size is very close to that obtained on gold nanoelectrode, and higher than that at large graphene flake. Unlike the high electronic DOS in gold nanoelectrodes, the difference of k(0) values at graphene nanoelectrodes of different sizes will reveal the size-dependent DOS at single graphene flake.