According to effective medium and percolation theory, the metal film must be dense and continuous enough to reach the percolation threshold that can behave metal-like in optics (reflecting the electromagnetic wave). However, the "Cu-phobic" surface of bare graphene can only form a sparse Cu particles film, and thus the deposited film is not reflective enough for mid-IR radiation. On the contrary, the Cu can grow uniformly and coherently on the "Cu-philic" surface of the Pt-modified graphene, resulting in fast conversion to the metallic state after electrodeposition. As shown in Figure , with the same charge density of electrodeposition (0.175 C/cm 2 ), the Cu film grown on the Ptmodified surface possesses lower emissivity, contributing to a more considerable contrast in the mid-IR range.