Non-enzymatic hydrogen peroxide electrochemical sensor based on a three-dimensional MnO2 nanosheets/carbon foam composite

A new type of three-dimensional electrochemical sensor platform, MnO2 nanosheets/carbon foam (MnO2/CF) hybrid nanostructure, was successfully fabricated for the nonenzymatic detection of H2O2. The morphology, structure and composition of the 3D nanostructures were systematically characterized by electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Uniform and thin MnO2 nanosheets can be formed on the carbon foam after a simple chemical process by immersing the carbon foam in a KMnO4 aqueous solution. The content of MnO2 in the MnO2/CF composites was found to play a great role in its sensing performance for H2O2 detection. The MnO2/CF2 sample with a 24.5% MnO2 content showed the best performance among the studied MnO2/CF composites. The 3D hierarchical porous structure with thin MnO2 nanosheets can provide an enhanced electrochemically active surface area, high electrical conductivity and improved analyte diffusion, which makes it a promising electrochemical sensing platform. The electrochemical studies showed that the H2O2 sensor based on the MnO2/CF2 exhibited an excellent detection performance with a wide linear range from 2.5 x 10(-6) to 2.055 x 10(-3) M and a detection limit of 1.2 x 10(-7) M (S/N = 3). These results demonstrate that such 3D nanocomposites have promising application in electrochemical sensors.