Non-enzymatic amperometric detection of hydrogen peroxide using grass-like copper oxide nanostructures calcined in nitrogen atmosphere

• Unique grass-like CuO nanostructures prepared by simple hydrothermal reactions.
• The influence of calcination in N2 atmosphere on CuO nanostructures was discussed.
• Study of processing-structure-property relationship of different CuO samples.
• As-prepared sensors exhibited excellent electrochemical catalytic performance.
• As-synthesized sensors show great application potential of detecting H2O2.

In this research, grass-like CuO nanostructure was synthesized via a simple hydrothermal reaction at 100 °C for 6 h without using any surfactant. The as-prepared sample was further calcined at 500 °C for 1 h in nitrogen atmosphere for comparison. The surface morphology, crystal structure and chemical composition of the products were investigated by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and room temperature photoluminescence spectroscopy (PL). The as-synthesized samples were also characterized systematically by electrochemical methods including cyclic voltammetry (CV), amperometric detection (i-t) and electrochemical impedance spectroscopy (EIS). It was found that the sample prepared after calcination in a nitrogen atmosphere exhibited better electrochemical catalytic performance for the determination of H2O2. In addition, high sensitivity (119.35 μA/mM) and fast amperometric response (< 3 s) were achieved; mainly due to the large specific surface area of the grass-like morphology, efficient electron charge transfer property resulting from the increased crystallinity after calcination, as well as more available and active absorption sites induced by surface defects and the CuO/Cu2O heterostructure, thus making it one of the promising candidates for the efficient and sensitive non-enzymatic amperometric detection of H2O2.