This review presents a critical and comparative analysis of carbon-based electrochemical sensing platforms for the determination of heavy metal ions in water, with emphasis on Pb²⁺, Cd²⁺, and Hg²⁺. The growing discharge of industrial and mining effluents has led to persistent contamination of aquatic environments by toxic metals, creating an urgent need for sensitive, rapid, and field-deployable analytical technologies. Carbon-based nanomaterials, including graphene, carbon nanotubes (CNTs), and MXene, have emerged as key functional components in modern electrochemical sensors due to their high electrical conductivity, large surface area, and tunable surface chemistry. Based on reported studies, typical detection limits for Pb²⁺ and Cd²⁺ using differential pulse voltammetry (DPV) on glassy carbon and thin-film electrodes are in the range of 0.4–1.2 µg/L. For integrated thin-film sensing systems, limits of detection of 0.8–1.2 µg/L are commonly achieved. MXene-based platforms further enhance sensitivity and enable Hg²⁺ detection with linear response ranges typically between 1 and 5 µg/L, accompanied by clear electrochemical or optical signals. Beyond conventional electrochemical detection, this review specifically highlights self-sustaining visual sensors based on MXene integrated with enzyme-driven bioelectrochemical systems, such as glucose oxidase (GOD) and Prussian blue (PB) assembled on ITO substrates. These systems convert chemical energy into measurable colorimetric signals without external power sources, enabling direct visual identification of Hg²⁺ ions. Under optimized conditions (e.g., 5 mg/mL GOD and 5 mM glucose), stable and distinguishable color responses are achieved for rapid on-site monitoring. Overall, this review not only summarizes current performance benchmarks of carbon-based sensors but also identifies key challenges, including long-term stability, selectivity under multi-ion interference, and large-scale device integration, while outlining future directions toward portable multisensor water-quality monitoring systems.

One of the strongest and most common chemical pollution is its environmental pollution with heavy metals. Heavy metals are actively involved in biological processes, which are part of many enzymes. The toxicity of heavy metal ions causes a number of harm to environmental components and human health. That is why the detection of heavy metals is so important. The creation of a reliable and effective system for detecting heavy metals is crucial. And traditional detection methods are often not enough to meet the current needs. Therefore, the use of electrochemical sensors in the detection of heavy metals is currently taking an important place. Electrochemical sensors have become a promising area of research due to their unique capabilities. Improving the detection efficiency of electrochemical sensors is the main area of research. The leading strategy for significantly improving detection performance involves adding nanomaterials to electrochemical sensors. This review compares MXene nanocompasites with the achievements of nanomaterials in the field of electrochemical sensors in recent years. This makes it possible to obtain new ideas for the manufacture of electrochemical sensors with high sensitivity and low detection threshold. We believe that knowing and combining the benefits of different nanomaterials to produce innovative electrode modification materials can eliminate the risk of heavy metal ions in many food, environmental and other industries.

Electrochemical sensors are one of the most important technologies in modern analytical chemistry and enable high-precision analyses. In this study, the efficiency of electrochemical sensors based on nanomaterials, as well as their sensitivity, selectivity, detection limit, and stability, were analyzed. The study investigated the analytical capabilities of sensors based on carbon nanotubes (CNTs), graphene, metal nanoparticles (Au, Pt, Ag), metal oxides (ZnO, CuO, Fe3O4), and metal-organic frameworks (MOFs). Nanomaterials play an important role in improving the sensitivity of electrochemical sensors. The large surface area and high conductivity of carbon nanotubes improve the adsorption of analytes on the electrode surface, thus enabling the detection of their low concentrations. The two-dimensional structure of graphene amplifies electrochemical signals and helps to shorten the analysis time. Metal nanoparticles and metal oxides increase the reaction rate and activate redox processes on the electrode surface. The high porosity of MOF structures enables the effective detection of heavy metal ions and organic pollutants. Research results show that the composition of the nanomaterials used in sensor devices significantly affects their sensitivity and stability. Their chemical and structural modification improves the long-term performance of the sensors. In the future, the development of multicomponent hybrid sensors and the optimization of their industrial applications are particularly relevant.