Electrocatalytic glucose oxidation on a combinatorially electrodeposited cobalt-copper-nickel thin film material library

A Co–Cu–Ni thin film material library was fabricated using a modified 3D-printed Hull cell. Rather than previous one by one attempts a combinatorial approach was here not to miss the exact optimum performance composition. An optimum activity at Co-16 at.% Cu-12 at.% Ni for the electrocatalytic glucose oxidation was found by screening along the compositional spread using flow-type scanning droplet cell microscopy (FT-SDCM). Crystallographic properties, surface microstructure and surface topography were investigated along the entire compositional spread using X-ray diffraction (XRD), scanning electron microscopy (SEM) as well as atomic force microscopy (AFM), respectively. The entire compositional spread (Co 40–76 at.%, Cu 0–19 at.% and Ni 11–60 at.%) showed suitability for being used in glucose detection, as determined by cyclic voltammetric measurements. A maximum response for glucose electrooxidation was identified at a Ni content of 12 at.% with a current density value of 21.8 mA cm−2. The performance of a glucose sensor constructed using this identified thin film alloy was evaluated by localised amperometric detection. A linear behaviour was obtained for a wide range of glucose concentrations in the electrolyte solution between 1 mM and 100 mM. Additionally, the identified thin film alloy showed high stability, good electrooxidation reproducibility and high selectivity, thus indicating its suitability for being used as catalyst in glucose detection.