High performance Mo₃C₂ MXene‑carbon black nanocomposites electrochemical sensor for sensitive detection of nitrite in environmental water samples

Considering the profound hazards of excessive nitrite on both the environment and public health, devising a rapid, advanced, and groundbreaking detection approach stands as an imperative step toward environmental preservation and the betterment of human life. In this work, we introduce a pioneering electrochemical sensor, augmented by an advanced molybdenum carbide (Mo₃C₂) MXene and carbon black (CB) nanocomposite, for ultra-precise detection of nitrite. The morphological features, structural characterization, and electrochemical properties of the Mo₃C₂ MXene/CB nanocomposite are analyzed using field emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectrometry, electrochemical impedance spectroscopy, and cyclic voltammetry. Mo₃C₂ MXene, as a novel material, has high conductivity, rich Mo edge sites, and a large surface area, ensuring efficient electron transfer, stability, and flexibility for low-noise sensing. Moreover, the combined properties of Mo₃C₂ MXene and CB enhance its conductivity and functionalization, making it an ideal component for low-cost electrochemical devices. Accordingly, the Mo₃C₂ MXene/CB nanocomposite-modified glassy carbon electrode exhibited a detection limit of 0.4 μM and demonstrated a broad linear range of 0.8–875 μM for nitrite detection in amperometric (i–t) measurements. In contrast, the CV method showed linear behavior in the range of 100–1200 μM. Besides, this sensor also delivers prominent reproducibility, stability, and feasibility of nitrite sensing in three real environmental samples (tap, rain, and river water). Therefore, this nanocomposite could pave the way for next-generation electrochemical sensing with optimized performance.