Facile synthesis of copper oxide nanostructures and their application in non-enzymatic hydrogen peroxide sensing

• Simple hydrothermal preparation method without using any additive.
• A possible formation mechanism of different CuO nanostructures was proposed.
• Study of precursor–structure–property relationship among various CuO nanostructures.
• As-prepared sensors exhibited excellent electrochemical catalytic performance.
• As-synthesized sensors show great application potential of detecting H2O2.

In this research, different CuO nanostructures (heart/dumbbell-like and grass-like) were successfully synthesized via simple hydrothermal reactions at 130 °C with different amounts of Cu(NO3)2·2.5H2O in 20 mL H2O and 12 mL NH3·H2O for 6 h in the absence of any additive. The initial amount of Cu(NO3)2·2.5H2O was found to be critical for CuO morphology evolution. In addition to morphology study by scanning electron microscopy (SEM) and crystal structure study by X-ray diffraction (XRD), as-synthesized samples were characterized systematically by electrochemical methods including cyclic voltammetry (CV), amperometric detection (i–t) and electrochemical impedance spectroscopy (EIS). It was found that both heart/dumbbell-like and grass-like CuO nanostructures exhibited good electrochemical performance toward low concentrations of H2O2. High sensitivity, fast and linear response were achieved, which was mainly due to their large specific surface areas and efficient electron transport in corresponding reactions, making them promising candidates for efficient and precise non-enzymatic detection of H2O2.