Non-enzymatic glucose sensors based on electrodeposited Cu_xO–ZnO composite nanostructures

Abstract

The present study investigates the non-enzymatic glucose sensing properties of Cu$_x$O–ZnO (x = 1,2) composite nanostructures that have been fabricated using a simple and fast co-electrodeposition (CED) method. Two concentrations of Cu$^{2+}$ were used and interestingly, for the lower concentration, the fabricated (C$_2$) nanostructures are of Cu$_2$O–ZnO type while for the higher concentration (C$_{50}$), nanostructures show a mixed Cu$_x$O–ZnO (x = 1,2) nature. Although both the samples exhibit a good catalytic response for non-enzymatic glucose sensing, the C$_{50}$ sample shows a far superior response. Along with a high sensitivity of 384.6 µA mM$^{-1}$ cm$^{-2}$, a large linear range of 0.03–3 mM, and a low least detection limit (LOD) of 0.7  µM, C$_{50}$ also demonstrates a good long-term stability, good reproducibility, and good selectivity toward glucose detection, even in the presence of interfering species. The synergistic effect of Cu$_x$O–ZnO composite nanostructures and their semiconducting nature may be contributing to the good response of C$_{50}$ as a glucose sensor. The results presented here demonstrate that C$_{50}$ can be an excellent non-enzymetic glucose sensor for measuring glucose in blood and food samples.