To evaluate the chemical compositions of each coating (more specifically, the carbon-tocopper content ratio), a portion of each coating was mechanically cleaved from the substrate, before grinding and elemental analysis by AAS and ICP-OES. The results are shown in Table . In both ML (Ni) and ML (Cu) coatings, there are 0.96 and 0.82 wt.% carbon contents (vs. copper content; ≈ 4.9 and 4.2 at.%), with trace hydrogen and nitrogen present in the system (< 0.3 wt%). The carbon content in these films is anticipated to come from the GnP nanosheets within, as the GnP-free ML (Ni) coating only contains a trace amount of carbon.