| Graphene has attracted significant attention because of it excellent physical properties and great potential applications.Chemical vapor deposition?CVD?method has emerged as a promising technique for realizing graphene preparation using metal Cu catalytic substrates.However,this method is still imperfect in the suppression of nucleation density,which is detrimental to the domain size of single-crystal graphene.In this paper,the cleanliness and oxygen content of Cu foil surface are optimized by plasma treatment,which effectively controls the nucleation density of graphene and increases graphene growth rate.The Cu foil resolidifies into a smooth Cu?111?film after annealing above the Cu melting point under the H2 atmosphere,and the single-crystal graphene film is obtained by seamless stitching single-crystal graphene domains.A high specific surface area three-dimensional?3D?graphene network is prepared by using oxidized Cu-Ni alloy foam as a template.The preparation of graphene is expanded from two dimensions to three dimensional and rich graphene applications.In this paper,the preparation and application of graphene materials are systematically studied,including the following contents:?1?The plasma treatment can effectively decompose impurities of Cu foil surface,which reduces the active sites for single-crystal graphene nucleation.Meanwhile,CuO nanoparticles are formed on the Cu foil surface by the plasma treatment,which can be reduced partly and produce oxygen after annealing at high temperature in H2atmosphere to promote the rapid growth of graphene.Eventually,we have achieved the synthesis of single-crystal graphene with large-size of about 5 mm,fast growth rate of 2.5 mm?h-1,high uniformity?monolayer coverage of 90%?and high field-effect mobility of 12500 cm2?V-1?s-1.Our work provides a facile and effective method for the fabrication of large-size single-crystal graphene.?2?The Cu foil resolidifies into a smooth Cu film and recrystallizes into single-crystal Cu film stick to Mo foil surface after annealing above the Cu melting point under the H2 atmosphere.The single-crystal graphene film of 3×4 cm2is obtained by seamless stitching oriented single-crystal graphene domains on the resolidified Cu?111?surface.The as-synthesized single-crystal graphene film is further confirmed more than 99%ultra-highly oriented domains,low sheet resistance of about 315?·sq-11 and high optical transmittance of 97.7%.Moreover,the field-effect mobility of the single-crystal graphene film reaches up to 11500 cm2?V-1?s-1,significantly higher than that of polycrystalline graphene film(4260 cm2?V-1?s-1).This approach provides a new idea for large-scale production of single-crystal graphene film.?3?The Cu-Ni alloy foam is oxidized at low temperatures in the air to create rich pores as a growth template.The prepared 3D graphene network has a self-supporting framework,which can be used as a collector.At the same time,it has high specific surface area for efficiently composite active materials.The specific capacitance of the prepared 3D graphene is increased by about 1400 F·g-11 after electrochemically compositing polyaniline?PANI?in situ.PANI on a 3D graphene network can provide a remarkable synergistic augmentation for improved supercapacitive performance. |
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