Mesoporous nickel electrodes plated with gold for the detection of glucose

Mesoporous nickel electrodes (MNEs) are efficient structural materials for advanced electrochemical sensors due to their extremely high surface areas. However, the poor oxidation resistance of nano-sized nickel in air severely limits their applications. Thus, the purpose of the present study was to improve the oxidation resistance of MNEs by applying relatively stable gold coatings via electroplating. The results revealed that the gold coatings provided excellent oxidation resistance to MNEs, and a loss in amperometric sensitivity for glucose sensing was not observed. The protection time increased with an increase as the thickness of the gold coating (passing charges of 0–25.49 C/cm2), and protection times ranging from a few hours to 2 weeks were obtained. With an alkaline electrolyte (NaOH, 4 M), MNEs exhibited excellent sensitivities. For instance, the sensitivity of the unmodified MNE and the Au coated-MNE was 3238 and 2978 μA mM−1 cm−2, respectively. Thus, coated and uncoated MNEs displayed remarkably higher linear sensitivities than conventional nickel-based electrodes (394 μA mM−1 cm−2) at a wide range of glucose concentrations (0.001–3 M).