Electrochemical synthesis of mixed-valence manganese/copper hybrid composite using graphene oxide and multi-walled carbon nanotubes for nonenzymatic glucose sensor

Abstract

Electrochemical synthesis of mixed-valence manganese/copper hybrid composite has been successfully performed using graphene oxide (GO) and multi-walled carbon nanotubes (MWCNT) as a conductive and steric hybrid nanotemplate. The MnCu/MWCNT/GO hybrid composite shows compact and nanoporous structure due to high conductivity and high specific surface of the MWCNT/GO nanotemplate. XRD result indicates a mixed-valence hybrid composite including copper manganese oxide (CuMn2O4), tenorite (CuO), and hausmannite (Mn3O4). It is electroactive, pH-dependent, and stable in the electrochemical system. It shows eletrocatalytic activity to glucose oxidation with high current response and low overpotential by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV). Particularly, DPV shows lower oxidation peak potential (Epa=−0.05V) due to suitable control of pulse parameters. CV, LSV, and DPV response of MnCu/MWCNT/GO shows linear correlation between current response and glucose concentration estimated with sensitivity of 49.1, 58.6, and 59.3μAmM−1cm−2, respectively. It shows linear concentration range of 1–32mM with a detection limit of 1×10−6M (S/N≧3). Coimmobilization and activity of manganese/copper hybrid composite can be effectively enhanced by MWCNT/GO. The MnCu/MWCNT/GO sensor shows high recovery and low coefficient of variation in bovine serum albumin samples for nonenzymatic glucose sensor.