Synthesis of single-crystal monolayer graphene on Cu/Ni(111) alloy foil.

Graphene has attracted broad interest due to its electrical, thermal, mechanical and chemical properties, showing great promise for applications such as lightweight aerospace structures, high-performance microelectronics and efficient thermal management systems. Chemical vapor deposition on metal substrates is currently the most viable route for scalable production of large-area and high-quality graphene films. However, the synthesis typically relies on costly single-crystal metal substrates, while further refinement is needed in both efficient growth and transfer techniques to achieve reproducible high-performance materials. To address these challenges, home-made single-crystal Cu/Ni alloy foils with tunable Ni concentrations can enhance catalytic activity, thereby providing an ideal platform for controllable graphene epitaxy. Here we detail a comprehensive protocol covering the fabrication of large-area single-crystal Cu foils, preparation of single-crystal Cu/Ni alloy foils, chemical vapor deposition growth of monolayer graphene and electrochemical transfer of graphene. The entire procedure requires ~32-38 h. This protocol is intended for researchers in materials science, surface chemistry, condensed matter physics and nanotechnology, and engineers seeking to obtain high-quality single-crystal metal foils and single-crystal monolayer graphene films. It provides a reproducible, scalable approach for their preparation and characterization, targeting fundamental research and potential applications in electronics and photonics.