Self-assembly of porous copper oxide hierarchical nanostructures for selective determinations of glucose and ascorbic acid

Abstract

The simple design of CuO micro-/nanostructures has recently attracted tremendous interest particularly for the enzyme-less sensing of biological molecules due to their intrinsic electronic and catalytic properties. Consequently attention has been directed to the development of new CuO nanomaterials that have multi-interdisciplinary applications. Herein, we report for the first time the fabrication of hierarchical porous CuO micro-/nanostructures with flower- and hollow sphere-like morphology via a facile hydrothermal method. Our experimental findings clarify that the source of the copper-ions effectively control the assembly of CuO nano-building blocks via the one-step hydrolysis of [Cu(NH₃)₄(H₂O)₂]SO₄ and [Cu(NH₃)₄(H₂O)₂]Cl₂ precursors, which produce hollow sphere and flower-like morphologies for sensitive and selective determination of ascorbic acid and glucose, respectively. Moreover, such unique properties of macro-/mesoporous CuO with defined dimensions and topologies offer minimized diffusive resistance for the dispersion of active sites. The best performance of the glucose and ascorbic sensor can be obtained at +0.55 V in 0.1 M sodium hydroxide solution. The as-prepared CuO modified (drop-casted) screen-printed electrodes (SPE) exhibit a fast electroactive response with high sensitivity within a wide concentration range of glucose and ascorbic acid in real samples. Significantly, the anion-dependent approach might be used to control effectively the expansion and features of other metal oxide micro-/nanostructures.