CoOx nanoparticles modified CuBi2O4 submicron-sized square columns as a sensitive and selective sensing material for amperometric detection of glucose

In this study, CoOx nanoparticles decorated CuBi2O4 submicron-sized square columns (microCuBi2O4|CoOx) modified electrodes were fabricated and their electrocatalytic properties were investigated. microCuBi2O4, for the first time, was directly grown onto the electrode substrate using chemical bath deposition (CBD) at room temperature, whereas microCuBi2O4|CoOx was prepared by subjecting microCuBi2O4 to additional CBD process and subsequent electrochemical treatment. It was found that the crystalinity of microCuBi2O4 and the amount of CoOx play a decisive role in the overall electrocatalytic activity of microCuBi2O4|CoOx. In addition, the redox couples of the active species, responsible for the electrocatalytic glucose oxidation, in microCuBi2O4 and CoOx overlaps, and these active species exert a synergetic electrocatalytic effect in enhancing the overall electrocatalytic activity, in terms of overpotential and catalytic current, of microCuBi2O4|CoOx towards glucose oxidation. Under optimal conditions, the developed microCuBi2O4|CoOx exhibits a promising sensing characteristics for glucose detection, including a high sensitivity of 383.0 ± 32.3 µA/cm2/mM, a low limit of detection of 0.8 µM, a wide linear range upto 8.0 mM, a fast response time (t95) of