Optimization growth of graphene on annealed copper and its application as glucose sensor material

The surface quality of copper substrate such as roughness, grain boundaries, defects and impurity particles play an important role on the nucleation and growth of graphene. Hence the growth of high quality graphene strongly rely on the outstanding surface of Cu substrate. On this account, in this research, the original commodity Cu foil was cleaned by various reagents and annealed at high temperature for optimizing the surface of the Cu foil. Compared with the graphene product from the original substrate, graphene grew on annealed substrate showed a better quality. By analyzing the characterization results of Cu foil before and after pretreatment, it was obtained that after pretreating, the impurities on the surface of the Cu foil disappeared and recrystallization occurred, which was conducive to forming a smoother surface of copper foil, and also growing larger area and higher quality graphene. Afterwards, the high quality graphene was used to prepare glucose sensor by photolithography, vacuum evaporation and glucose oxidase modification, which is simply fabricated without other complex processes. After sample testing, the glucose sensor based on graphene revealed two linear dynamic ranges of 0 mM–1.39 mM with a sensitivity of 97 μA mM−1 and 2.78 mM–11.11 mM with a sensitivity of 3 μA mM−1. Additionally, the as-prepared glucose sensor exhibited excellent resistance to interferences from other substances as well as superior reproducibility. The most important is the sensor is highly stable for a long time without current attenuation to a large extent. All the results illustrate the as-prepared glucose sensor offers an effective and convenient approach for glucose detection and analysis.