Ultrathin 2D/2D nanohybrid for efficient electrochemical detection of nitrite

An excessive amount of nitrite ions and their long-term accumulation pose a significant threat to both the ecological system and the public health. Thus, it is highly desirable to construct a unique electrode architecture for the precise and efficient quantification of nitrite. This study reports an electrochemical nitrite sensor using an ultrathin 2D/2D hematene/GO nanohybrid with a few nanometers of thickness and face-to-face contact. Due to their high surface-to-volume ratio, which make them extremely susceptible to their interaction with the surrounding environment, and the high density of active surface sites, they exhibit remarkable electrochemical sensing performance towards nitrite. The proposed ultrathin 2D/2D hematene/GO nanohybrid sensor responds linearly with increasing concentrations of nitrite up to 1000 µM and a low detection limit (2 µM). In addition, the sensor's selectivity, stability, and reproducibility qualities are also evaluated. Furthermore, it successfully detected the analyte in tap water, mineral water, and river water samples with relative standard deviations (RSD) less than 5%. Density functional theory (DFT) simulations demonstrate that the hematene/GO nanohybrid efficiently lowers the energy barrier for the electrochemical oxidation of HNO2 to HNO3 and that the synergistic impact of hematene and GO enhances the electrochemical sensing reactivity for the reaction of nitrite detection.