Ionic-liquid-enhanced glucose sensing ability of non-enzymatic Au/graphene electrodes fabricated using supercritical CO2 fluid

Nano-sized Au particles (approximately 10 nm in diameter) are uniformly distributed on both graphene and carbon nanotubes (CNTs) using a supercritical CO2 fluid (SCCO2), which has gas-like diffusivity, low viscosity, and near-zero surface tension. Since the Au nanoparticles are highly dispersed and tightly anchored on the carbon supports, the obtained nanocomposites exhibit an improved electro-oxidation ability toward glucose as compared to that of the control electrodes prepared using a conventional chemical deposition process (without SCCO2). The Au/CNT electrode shows a higher glucose sensing current than that of the Au/graphene counterpart, which is due to the three-dimensional architecture interwoven by the CNTs creating a larger number of reaction sites. However, with ionic liquid (IL) incorporation, the detection sensitivity of the latter electrode significantly improved, becoming noticeably greater than that of the former. The synergistic interactions between Au/graphene and IL that lead to the superior electrochemical detection performance are demonstrated and discussed.

► Supercritical CO2 can uniformly disperse Au nanoparticles on graphene and CNTs.
► The proposed electrodes show an improved electro-oxidation ability toward glucose.
► The Au/CNT shows a higher sensing current than that of the Au/graphene electrode.
► With ionic liquid (IL), the glucose detection currents at the electrodes increase.
► With IL, the sensitivity of Au/graphene becomes greater than that of Au/CNT.