Comparison of Copper(II) Oxide Nanostructures with Different Morphologies for Nonenzymatic Glucose Sensing

The glucose sensitivity achieved with copper(II) oxide particles with three different morphologies (spheres, platelets, and needles) for application in nonenzymatic glucose sensors was investigated. The morphologies of CuO nanoparticles were controlled by different synthesis parameters, including changes in precipitators of Cu(II) ions, pH values, calcination protocol, and the addition of surfactant and hydrogen peroxide. The role of copper(II) oxide particle morphology in nonenzymatic glucose sensing was studied. The primary driving factor in the electrocatalytic process was investigated for several morphological properties of the material. We studied the effects of exposed crystal faces, specific surface area, pore volume, and grain size of copper oxides on glucose sensitivity. This study showed that the electrocatalytic performance in glucose sensing correlates primarily with the grain size of copper oxide nanoparticles and the capacitance introduced therefrom. The needle-shaped CuO nanoparticles presented the optimal morphology in this application, resulting in good sensitivity to glucose (2.05 mA·mM^-1·cm^-2), a linear range of 0.05-5 mM glucose, and the best long-term stability among these materials. This work provides insight into the potential use of CuO-based materials in biosensors and into the major contributing factors of metal oxide-based nanoparticles in sensing applications.