Nickel-Foam-Supported Co3O4 Nanosheets/PPy Nanowire Heterostructure for Non-enzymatic Glucose Sensing

Graphical Construction zone : The Co 3 O 4 /PPy nanostructure possesses structural features of a nanowire core and nanosheet shell grown directly on a nickel foam substrate by electrochemical deposition processes. The PPy nanowires are introduced onto the nickel foam, which create a three-dimensional structure and the Co 3 O 4 nanosheets shell act as a catalyst for the electro-oxidation of glucose. Cobalt oxide nanosheets (Co 3 O 4 NSs)/polypyrrole nanowire (PPy NW) core-shell nano-heterostructures based on nickel foam (NF) were fabricated for electrochemical non-enzymatic glucose determination. The Co 3 O 4 /PPy nanostructures grew directly on nickel foam substrate by electrochemical deposition processes. The PPy NW core and the Co 3 O 4 NS shell constructed the hierarchical nanocomposites to form a three dimensional micro−nanostructure in the micropores of NF. The as-prepared Co 3 O 4 /PPy/NF heterostructures were characterized by using scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The introduction of the Co 3 O 4 NSs can provide a high surface area and lead to high sensitivity to glucose. Chronoamperometry was used to evaluate the sensitivity of the sensor toward glucose. Compared with NF, PPy/NF, and Co(OH) 2 /PPy/NF electrodes, the Co 3 O 4 /PPy/NF electrode exhibited higher electrocatalytic activity for the oxidation of glucose, and the proposed glucose sensor showed linear electrochemical responses to glucose with a low detection limit of 0.74 μM (S/N=3). In addition, the prepared biosensor revealed good selectivity in the presence of electro-active species such as d -fructose, uric acid, ascorbic acid and hydrogen peroxide, and provided an excellent platform for the determination of glucose in human urine samples.