Nonenzymatic detection of glucose using three-dimensional PtNi nanoclusters electrodeposited on the multiwalled carbon nanotubes

A novel enzyme-free glucose sensor is developed with the three-dimensional (3D) PtxNi1-x (x=0.1–0.9) alloy nanoclusters electrodeposited onto multi-walled carbon nanotubes (MWCNTs). The synthesis, structural, and compositional characterization of 3D PtxNi1-x/MWCNTs are reported. Cyclic voltammetry, linear sweep voltammetry, kinetic analysis, electrochemical impedance plots, and amperometric responses exhibit that the 3D PtxNi1-x/MWCNTs nanocomposites have more remarkable catalytic performance on the direct oxidation of glucose comparing with the 3D Pt/MWCNTs catalysts and the uniform dispersive morphology PtxNi1-x/MWCNTs catalysts. We further investigate how the Pt/Ni atomic ratios of these alloys play a key role in controlling the electrocatalytic activity and thus improve the glucose detection. The optimal Pt/Ni atomic ratio acquired in present experiment condition is 3/7, which proves linearity up to 15mM of glucose with a sensitivity of 0.94mA/mMcm2 and a detection limit of 0.3μM (S/N=3) at −0.30V. Meanwhile, the interference from dopamine, uric acid, p-acetamidophenol, ascorbic acid, urea, galactose, lactose and fructose is effectively avoided at this negative potential. The as-synthesized sensor is applicable to the glucose sensing in the real human serum with the concentrations agreeing well with that measured by a hospital. Furthermore, 90% of the surface active sites and the initial sensitivity are retained in continuous tests (31 days), proving favorable long-term stability.