Fast and clean dielectric barrier discharge plasma functionalization of carbon nanotubes decorated by electrodeposited nickel oxide: Application to glucose biosensors

In this study, multi-walled carbon nanotubes (MWCNTs) were functionalized through dielectric-barrier-discharge plasma in the presence of the H2O-saturated atmosphere at 70C and atmospheric pressure. The functionalized MWCNTs (F-CNTs) were decorated with 10 nm electrochemically deposited nanoparticles of NiO followed by glucose oxidase (GOx) immobilization, and the treated electrode was used for glucose detection. TEM, FE-SEM, TPD, and XPS techniques were used to characterize NiO/FCNTs samples. The maximum extent of oxygen-containing functional groups, including carbonyl, hydroxyl, and carboxylic groups, formed in the plasma contact time of 4 min. The optimum time for the chronoamperometric deposition of NiO was 3 min. The presence of GOx on the NiO/F-CNTs electrode displayed a quasi-reversible and surface-controlled reduction-oxidation wave at 􀀀0:52 V. The peak separation of this wave is 0.05 V. The GOx/NiO/F-CNTs electrode showed a linear performance at a glucose concentration of 0.2-3.8 mM with a sensitivity rate of 2.16 A/mM and a detection limit of 93.0 M.