Zinc and sulfur codoped iron oxide nanocubes on functionalized multiwalled carbon nanotubes (Zn@S-FeNC/f-CNTs) were synthesized by a conventional hydrothermal (HT) route followed by ultrasonication, and the synthesized nanocomposites were used for the sensitive and selective detection of isoniazid (INZ). The morphological, structural, and electrochemical properties of the composite were well characterized. The application of the screen-printed carbon electrode modified with Zn@S-FeNC/f-CNT for the detection of antibiotic drug INZ (for the treatment of tuberculosis, TB) by employing voltammetric and amperometric techniques. The composite served as an outstanding electron (e − )-transfer mediator for INZ oxidation. Under optimum conditions, the modified electrode showed a distinct response for voltammetric and amperometric analyses toward INZ detection, yielding low detection limits of 5.01 and 8.54 nM, respectively. The calculated charge-transfer rate constant (k s ) was 1.6 × 10 −6 cm s −1 , while the electrochemical active surface area was estimated to be 0.157 cm 2 . The fabricated sensor exhibited good selectivity, long-term stability, and high reproducibility. The sensor has been further used to examine human serum and urine samples with good recovery.

In this review, ruthenium nanoparticles (Ru NPs)-based functional nanomaterials have attractive electrocatalytic characteristics and they offer considerable potential in a number of fields. Ru-based binary or multimetallic NPs are widely utilized for electrode modification because of their unique electrocatalytic properties, enhanced surface-area-to-volume ratio, and synergistic effect between two metals provides as an effective improved electrode sensor. This perspective review suggests the current research and development of Ru-based nanomaterials as a platform for electrochemical (EC) sensing of harmful substances, biomolecules, insecticides, pharmaceuticals, and environmental pollutants. The advantages and limitations of mono-, bi-, and multimetallic Rubased nanocomposites for EC sensors are discussed. Besides, the relevant EC properties and analyte sensing approaches are also presented. On the basis of these insights, we highlighted recent results for synthesizing techniques and EC environmental pollutant sensors from the perspectives of diverse supports, including graphene, carbon nanotubes, silica, semiconductors, metal sulfides, and polymers. Finally, this work overviews the modern improvements in the utilization of Ru-based nanocomposites on the basis for electroanalytical sensors as well as suggestions for the field's future development.

In this study, an alternative precursor for production of biomass-derived activated carbon was introduced using dragon fruit (Hylocereus costaricensis) peels. Chemical activators such as FeCl3, MgCl2, ZnCl2 were used in the thermal carbonization process to convert carbon into porous carbon (PC). However, heteroatom-doped PC catalysts including N-, B-, and P-doped carbon catalysts in the field of dye removal is highly desirable. Several approaches (XRD, FE-SEM/TEM, XPS, FT-IR, EDS, and elemental mapping) were employed to examine the surface morphology, surface properties, and elemental composition of the PC catalyst. The catalytic activity of metal-free PC catalyst was demonstrated for methylene blue (MB), crystal violet (CV), and Nile blue (NB) in a mild environment The corresponding rate constant (kapp) values were estimated as 0.2473, 0.3248, and 0.3056 min−1, respectively, for MB, CV, and NB, which were significantly greater than those of numerous reports. It exhibited the best catalytic activity and recyclability. Moreover, the approach proposed here could create new opportunities for the remediation of organic dyes in lakes and industrial wastewater.