A novel strategy for realizing highly sensitive nonenzymatic detection of H2O2 based on regulating crystallinity of CoO nanosheets

This study reports a novel strategy to construct a highly sensitive H2O2 electrochemical sensor by regulating the crystallinity of CoO nanosheets. [Display omitted] •This study reports a novel strategy to construct a highly sensitive electrochemical sensing method by regulating the crystallinity of CoO nanosheets.•It is interesting to find that the crystallinity has a significant effect on the electrochemical surface area and electron transport rate.•The sensor based on CoO nanosheets with low crystallinity exhibits excellent performance for H2O2 analysis.•This study provides a novel strategy to design efficient electrocatalyst for applications. This study reports a novel strategy to construct a highly sensitive electrochemical sensing method based on crystallinity regulation. Two kinds of CoO nanosheets with different crystallinity were prepared by adjusting annealing temperature. The results show that decreasing crystallinity of CoO nanosheets not only increases electrochemical surface area but also accelerates electron transport rate. This is beneficial to improve the electrocatalytic activity of CoO nanosheets for electrochemical oxidation of H2O2, and therefore makes the sensor detect H2O2 in a linear range of 0.2 µM to 11 mM, a sensitivity of 909.9 µA·mM−1·cm−2 and a low detection limit of 0.2 µM. This study provides a new perspective to regulate the electrocatalytic activity of nanomaterials for constructing highly sensitive electrochemical sensor.