Two-dimensional transition metal dichalcogenides (2D TMDs) have gained considerable attention due to their distinctive properties and broad range of possible applications. One of the most widely studied transition metal dichalcogenides is molybdenum disulfide (MoS₂). The 2D MoS₂ nanosheets have unique and complementary properties to those of graphene, rendering them ideal electrode materials that could potentially lead to significant benefits in many electrochemical applications. These properties include tunable bandgaps, large surface areas, relatively high electron mobilities, and good optical and catalytic characteristics. Although the use of 2D MoS₂ nanosheets offers several advantages and excellent properties, surface functionalization of 2D MoS₂ is a potential route for further enhancing their properties and adding extra functionalities to the surface of the fabricated sensor. The functionalization of the material with various metal and metal oxide nanostructures has a significant impact on its overall electrochemical performance, improving various sensing parameters, such as selectivity, sensitivity, and stability. In this review, different methods of preparing 2D-layered MoS₂ nanomaterials, followed by different surface functionalization methods of these nanomaterials, are explored and discussed. Finally, the structure–properties relationship and electrochemical sensor applications over the last ten years are discussed. Emphasis is placed on the performance of 2D MoS₂ with respect to the performance of electrochemical sensors, thereby giving new insights into this unique material and providing a foundation for researchers of different disciplines who are interested in advancing the development of MoS₂-based sensors.

Glutathione-capped copper sulfide (Cu_xS_y) nanoparticles with two different average sizes were successfully achieved by using a simple reduction process that involves only changing the reaction temperature. Temperature-induced changes in the size of Cu_xS_y nanoparticles resulted in particles with different optical, morphological, and electrochemical properties. The dependence of electrochemical sensing properties on the sizes of Cu_xS_y nanoparticles was studied by using voltammetric and amperometric techniques. The spherical Cu_xS_y nanoparticles with the average particle size of 25 ± 0.6 nm were found to be highly conductive as compared to Cu_xS_y nanoparticles with the average particle size of 4.5 ± 0.2 nm. The spherical Cu_xS_y nanoparticles exhibited a low bandgap energy (E_g) of 1.87 eV, resulting in superior electrochemical properties and improved electron transfer during glucose detection. The sensor showed a very good electrocatalytic activity toward glucose molecules in the presence of interference species such as uric acid (UA), ascorbic acid (AA), fructose, sodium chloride, and sucrose. These species are often present in low concentrations in the blood. The sensor demonstrated an excellent dynamic linear range between 0.2 to 16 mM, detection limit of 0.2 mM, and sensitivity of 0.013 mA/mM. The applicability of the developed sensor for real field determination of glucose was demonstrated by use of spiked blood samples, which confirmed that the developed sensor had great potential for real analysis of blood glucose levels.

The present study involves the synthesis of polyvinylpyrrolidone (PVP)-stabilized iron-based trimetallic nanoparticles with different metal addition sequences (Fe/Ag/Zn, Fe/Zn/Ag and Fe/(Zn/Ag)) using the sodium borohydride reduction method. In order to investigate the catalytic reactivity of the nanoparticles, a series of batch experiments were performed using methyl orange dye as a model pollutant. It was found that the Fe/Ag/Zn system showed the maximum catalytic activity compared to the other studied trimetallic systems. About 100% of the methyl orange dye was removed within 1 min and the second-order rate constant obtained was 0.0744 (mg/L)⁻¹ min⁻¹; the rate of reaction was higher than that of the other trimetallic systems. Furthermore, the effects of pH, initial dye concentration and nanoparticle dosage on the degradation of methyl orange were investigated. The results showed that the reactivity of the Fe/Ag/Zn trimetallic nanoparticles was highly dependent on the aforementioned parameters. Higher reactivity was obtained at lower pH, lower initial methyl orange dye concentration and higher nanoparticle dosage. Lastly, liquid chromatography–mass spectroscopy (LC-MS) was used to elucidate the reaction pathway and identify by-products from methyl orange degradation. The developed catalyst demonstrated exceptionally rapid and apparent degradation of methyl orange within one minute, outperforming previously reported bimetallic and trimetallic systems. This work reports a cost-effective nZVI-based trimetallic system containing minimal silver, which shows promising reactivity toward azo dye degradation and may be suitable for future application in textile wastewater treatment.

Abnormal dopamine (DA) levels in the human body are associated with severe health conditions, making their accurate detection crucial for early diagnosis and monitoring. Therefore, the development of a highly sensitive electrochemical sensor for DA detection is of significant importance in physiological, biochemical, pharmaceutical, and medical applications. In this study, screen-printed electrodes (SPEs) were fabricated using MoS₂-based conductive inks containing varying concentrations of silver nanoparticles (Ag NPs) to enhance electrocatalytic activity. The ink composition included ethyl cellulose and polyvinylpyrrolidone (PVP) as binders, providing structural integrity and adhesion, while terpineol was used as the solvent to achieve the desired viscosity for smooth and consistent printing. The printed electrodes underwent comprehensive electrochemical characterization to assess their performance, including stability, reproducibility, and sensitivity. Electrochemical analysis revealed that the SPCE/MoS₂-Ag,4 electrode exhibited the best sensing characteristics due to the optimized interaction between MoS₂ and Ag NPs, which facilitated improved electron transfer and enhanced detection capability. The electroanalytical performance of the sensors was assessed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry. The SPCE/MoS₂-Ag,4 sensor demonstrated a wide linear detection range from 0.01 to 0.08 mM and an exceptionally low limit of detection (LOD) of 0.016 μM for DA. Additionally, the sensor exhibited excellent reproducibility, high sensitivity, and strong selectivity, making it a promising candidate for reliable dopamine detection in biomedical and clinical applications.