Enhanced photocatalytic activity of Cu and Ni-doped ZnO nanostructures: A comparative study of methyl orange dye degradation in aqueous solution.

Heterogeneous photocatalysis has been considered one of the most effective and efficient techniques to remove organic contaminants from wastewater. The present work was designed to examine the photocatalytic performance of metal (Cu and Ni) doped ZnO nanocomposites in methyl orange (MO) dye degradation under UV light illumination. The wurtzite hexagonal structure was observed for both undoped/doped ZnO and a crystalline size ranging between 8.84 ± 0.71 to 12.91 ± 0.84 nm by X-ray diffraction (XRD) analysis. The scanning electron microscope (SEM) and energy dispersive X-ray (EDX) revealed the irregular spherical shape with particle diameter (34.43 ± 6.03 to 26.43 ± 4.14 nm) and ensured the purity of the individual elemental composition respectively. The chemical bonds (O-H group) and binding energy (1021.8 eV) were identified by Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) results respectively. The bandgap energy was decreased from 3.44 to 3.16 eV when Ni dopant was added to the ZnO lattice. The comparative photocatalytic activity was observed in undoped and doped nanocomposites and found to be 76.31%, 81.95%, 89.30%, and 83.39% for ZnO, Cu/ZnO, Ni/ZnO, and Cu/Ni/ZnO photocatalysts, respectively, for a particular dose (0.210 g) and dye concentration (10 mg L-1) after 180 min illumination of UV light. The photocatalytic performance was increased up to 94.40% with the increase of pH (12.0) whereas reduced (35.12%) with an increase in initial dye concentration (40 mg L-1) using Ni/ZnO nanocomposite. The Ni/ZnO nanocomposite showed excellent reusability and was found 81% after four consecutive cycles. The best-fitted reaction kinetics was followed by pseudo-first-order and found reaction rate constant (0.0117 min-1) using Ni/ZnO nanocomposite. The enhanced photodegradation efficiency was observed due to decreases in bandgap energy and the crystalline size of the photocatalyst. Therefore, Ni/ZnO nanocomposite could be used as an emerging photocatalyst to degrade bio-persistent organic dye compounds from textile wastewater.

Poly(3,4-ethylenedioxythiophene):Polystyrene Sulfonate-Modified Electrode for the Detection of Furosemide in Pharmaceutical Products.

Furosemide (4-chloro-2-(furan-2-ylmethylamino)-5-sulfamoyl benzoic acid) is a widely used, FDA-approved drug prescribed for several symptoms associated with heart, kidney, liver failure, or chronic high blood pressure. In this work, a glassy carbon working electrode modified with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate is developed to detect furosemide (FURO) with high sensitivity and precise selectivity. The modified electrode was also characterized using field emission scanning electron microscopy, attenuated total reflectance-Fourier transform infrared, and cyclic voltammetry. Here, an efficient and cost- and time-efficient technique to study the furosemide mechanism of reaction in an acidic liquid medium is presented. An electrochemical oxidation of loop diuretic furosemide was investigated in a supporting electrolyte, 0.01 M of phosphate buffer (at a pH level of 4.0) at 25 ± 0.1 °C using a differential pulse voltammetric (DPV) technique. Under optimized parameters, the developed sensor displays a wide detection range of furosemide concentrations of 6.0 × 10-6 to 1.0 × 10-4 M with a detection limit of 2.0 × 10-6 M using DPV. The presented sensor offers a robust and high-precision technique with an excellent reproducibility to detect furosemide in as a real sample such as urine and pharmaceutical products.

Recent Advanced in MXene Research toward Biosensor Development.

MXene is a rapidly emerging group of two-dimensional (2D) multifunctional nanomaterials, drawing huge attention from researchers of a broad scientific field. Reporting the synthesis of MXene was the following breakthrough in 2D materials following the discovery of graphene. MXene is considered the most recent developments of materials, including transition metal carbonitrides, nitrides, and carbides synthesized by etching or mechanical-based exfoliation of selective MAX phases. MXene has a plethora of prodigious properties such as unique interlayer spacing, high ion and electron transport, large surface area, excellent thermal and electrical conductivity, exceptional volumetric capacitance, thermal shock, and oxidation resistance, easily machinable and inherently hydrophilic, and biocompatibility. Owing to the abundance of tailorable surface function groups, these properties can be further enhanced by surface functionalization with covalent and non-covalent modifications via numerous surface functionalization methods. Therefore, MXene finds their way to a plethora of applications in numerous fields including catalysis, membrane separation, energy storage, sensing, and biomedicine. Here, the focus is on reviewing the structure, synthesis techniques, and functionalization methods of MXene. Furthermore, MXene-based detection platforms in different sensing applications are survived. Great attention is given to reviewing the applications of MXene in the detection of biomolecules, pathogenic bacteria and viruses, cancer biomarkers food contaminants and mycotoxins, and hazardous pollutants. Lastly, the future perspective of MXene-based biosensors as a next-generation diagnostics tool is discussed. Crucial visions are introduced for materials science and sensing communities to better route while investigating the potential of MXene for creating innovative detection mechanisms.