(Nb0.5Si0.5)xTi1 xO2 nanocomposites (x =0, 0.025, 0.05, and 0.1) were produced by the easy and versatile mechanical milling technique. Structural parameters, optical absorbance, surface area, and photocatalytic per formance towards methylene blue (MB) under ultraviolet–visible (UV–Vis) radiation were investigated. The structural analysis revealed the formation of rutile and brookite phases, confirming the good incorporation of Nb0.5Si0.5 inside the TiO2 lattice. The crystallite size of formed phases was slightly affected by the dopant and its average value is in the range of 5–7 nm. The morphology of composites is composed of spherical-like nano particles with an average particle size range of 10–22 nm, and the highest surface area (19.19 m2/g) was reached for (Nb0.5Si0.5)0.025Ti0.075O2. The FTIR, Raman, and XPS analyses indicated the formation of numerous Ti–O–Ti, Si–O–Ti, and Si–O–Si bonds and emphasized the formation of rutile and brookite phases. The optical band gap obeyed the direct transition mechanism, and its average values were 3.4, 3.82, 3.7, and 3.5 eV for x =0, 0.025, 0.05, and 0.1, respectively. The photodegradation efficiency (η) of TiO2 towards MB was enhanced by Nb0.5Si0.5 doping, catalyst dosage, pH value, and irradiation time. The maximum value of η towards MB was 76.6 % and was attained after UV–Vis irradiation for 140 min in the presence of 1 g of (Nb0.5Si0.5)0.025Ti0.075O2 catalyst per 1 L MB, with the highest rate kinetic constant of 1.02 ×10 2 min 1. The value of η increased up to 94.34 % by adjusting the pH to 10. The optimum catalyst dosage for the MB photodegradation (96.4 %) is 2 g/L. Moreover, the recycling experiments demonstrated adequate reusability for the investigated catalyst. Furthermore, the adsorbed dye on the surface of the catalyst has been investigated and the degraded products were analyzed using the GC-MS technique, with a postulated mechanism of degradation. Therefore, the prepared (Nb0.5Si0.5)xTi1 xO2 nanocomposites are suitable for the degradation of various toxic dyes and may apply to various technologies required for modulated optical band gaps such as UV photodetector.

Fano resonance is a sharp and asymmetric spectral feature that can be used for refractive index sensing. In this paper, we propose a Fano resonance sensor based on the coupling between a nanoring resonator and a metal-insulator-metal (MIM) waveguide. The nanoring resonator is fabricated in the middle of the MIM waveguide, and the two structures are coupled with high-field confinement. The transmission spectrum of the coupled structure shows a Fano resonance, which is sensitive to the refractive index of the surrounding medium. The sensitivity of the sensor is estimated to be 1700 nm/RIU, which is comparable to the sensitivities of other Fano resonance sensors. In addition, the designed sensor achieves the first-ever FOM and Q factor values of 4300.25 RIU-1 and 4310, respectively, for plasmonic MIM sensors. The proposed sensor is simple to fabricate and can be used for a wide range of refractive index sensing applications.
 

The structural parameters, optical properties, and dielectric constants at a frequency (f) range of 0.1–20 MHz, and temperature (T) range of 300–400 K of hydrothermally synthesized M/SnO2 nanocomposites (for simplicity M denotes oxides of Al, Ni, or Mn) were compared. Rietveld refined X-ray powder diffraction (XRD) analysis demonstrated the formation of hexagonal, cubic, or spinel crystal structures of Al2O3, NiO, or Mn3O4 phases, respectively, besides the tetragonal rutile crystal structure of SnO2. The impact of Al addition on the optical band gap of SnO2 is negligible while it decreased or increased by incorporation of Ni or Mn, respectively. The residual lattice dielectric constant of SnO2 was increased, while the real part of the dielectric constant and the ac con ductivity of SnO2 were decreased by M incorporation. The dielectric parameters are remarkably affected by selected M, T, and f values and their changes agree with the Maxwell-Wagner model. The Q-factor of SnO2 was increased by M addition while decreased with increasing T. The Ni/SnO2 obeys the hole conduction at T ≤330 K, while Mn/SnO2 and Ni/SnO2 obey the electronic conduction at T >330 K. The binding energy is independent of the chosen T for SnO2, whereas it sharply increases for Ni/SnO2 and slightly decreases for Al/SnO2 and Mn/SnO2. The F-factor of SnO2 was slightly decreased by M addition, but it was increased with T for SnO2, Al/SnO2, and Mn/SnO2 while was decreased for Ni/SnO2. The Cole-Cole plots for M/SnO2 composites were analyzed, and the components of the equivalent circuit were determined. The electrical impedance, resistance of grains, resistance of grain boundaries, and equivalent resistance of SnO2 were increased by M incorporation, whereas equivalent capacitance was decreased. The findings recommend the SnO2-based nanocomposites for applications in opto electronics, lithium batteries, supercapacitors, and solar cell devices.

Two novel thiosemicarbazone linked with 1,3,4-thiadiazole ligands were synthesized through the condensation reaction of the acetyl group at position 5 of 1,3,4-thiadiazole derivatives with thiosemicarbazide in acidic ethanol solution in addition to their Co(II)-complexes. The divalent cobalt complexes of both ligands have been synthesized through the reaction of cobalt acetate with each ligand leading to the formation of the two complexes [(LH)Co(OAc)]0.5H2O and [(LCl)Co(OAc) (H2O)2]; where LH and LCl are 1,3,4-thiadiazolethiosemicarbazone ligands. The two complexes have been proved to have tetrahedral and octahedral geometry from the results of UVeVis spectra and magnetic moment. Analysis of the IR spectra of both ligands and complexes ascertained that the ligands behaved as monobasic tridentate coordinating to the metal ion center through azomethine-nitrogen atoms and thiadiazole ring in addition to deprotonated SH group. The synthesized ligands and their complexes were also investigated as inhibitors for the corrosion of carbon steel in 1.0 M HCl using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscopy techniques. The obtained results revealed that the inhibition efficiencies of the tested derivatives were found to depend on the concentrations and structures of such derivatives, and were decreased with raising temperature. At the same inhibitors concentration, the inhibition efficiencies are slightly increased in the order: LH > LCl > LH-Co > LCl-Co. The results derived from all applied techniques are harmonious with each other.

The divalent copper, cobalt, nickel and cadmium in addition to the trivalent iron complexes of the ligand named (E)-1-((4,6- dimethylpyrimidin-2-ylimino)methyl)naphthalen-2-ol were synthesized by the reaction of the ligand with diferent metal chlorides. The Structures and geometry of the metal chelates have been successfully deduced applying various analytical and spectroscopic tools such as elemental analysis, molar conductance, TGA, magnetic moment measurements, IR, 1 H-NMR, EI-mass and UV–Vis spectral studies. The X-ray single crystal structure of the ligand has been also discussed. Spectral studies and analytical results supported the monobasic bidentate behavior of the ligand connecting the metal ion centers via deprotonated phenolic OH and imine nitrogen. In the case of Cu(II) complex, the pyrimidine nitrogen took part in coordination to the Cu center. The results ensured the monometallic character of the chelates having 1:2 (M:L) ratio for copper, cobalt and nickel and 1:1 (M:L) ration for iron and cadmium complexes. The molar conductance data ensured that all the metal complexes are non-electrolytic type of complexes. All the complexes have been proved to have octahedral geometry. The antimicrobial activities of the synthesized metal chelates were evaluated against diferent bacterial and fungal strains. The synthesized ligand and its complexes were also examined as inhibitors for the corrosion of mild steel in 1.0 M H2SO4 at 25 °C using various techniques. The experimental outcomes indicated that the inhibition efciencies of the tested compounds increased as their concentrations increase. The obtained inhibition efciencies were interpreted on the basis of strong adsorption of the inhibitor molecules on the surface of mild steel and composing good protection flms. The adsorption was found to obey Langmuir adsorption isotherm. The results achieved from all applied techniques are obviously compatible.

Degradation kinetics of antibiotics neomycin and streptomycin was explored spectrophotometrically via their oxidation by cerium(IV) in both sulphuric and perchloric acids. The oxidation reactions demonstrated a 1:8 stoichiometry (antibiotic:cerium(IV)). The kinetics of the reactions in the examined acidic media was first-order with respect to [cerium(IV)] and fractional-first orders with respect to examined antibiotics and H+ concentrations. In the perchloric acid solution, the oxidation reactions of both antibiotics manifested fractional-first-order credence in [H+], whereas the reactions that occurred in sulphuric acid solutions displayed negative less than unit order rate with [H+]. Additionally, different behaviours of the reactions in dissimilar acidic media regarding the influence of ionic strength were recorded. Tests for free radical involvement throughout the oxidation reactions were positive. Under the same circumstances, the rates of neomycin oxidation in both acidic media were lower than those of streptomycin, and those obtained in perchloric acid were higher than those of sulphuric acid for both antibiotic substrates. Conceivable oxidation mechanisms in both sulphuric and perchloric acids consistent with the obtained kinetic results were anticipated. Additionally, the derived rate-law expressions in both acids were in good accordance with the obtained kinetic results. The activation parameters of the oxidation reactions in the acidic media were assessed and debated.

The kinetics and mechanistic aspects of the oxidation of two beta-lactam antibiotics (A), ampicillin and flucloxacillin, by alkaline hexacyanoferrate(III) (HCF(III)) were examined using spectrophotometry at a fixed temperature. The oxidation reactions showed a 1:4 (A: HCF(III)) stoichiometry. The reaction kinetics were found to follow first-order dependence for the oxidant and fractional first-order dependence for [A] and [OH−]. The enhancement of the ionic strength and dielectric constant was found to increase the oxidation rates. Free radical tests of the reactions showed positive results. The addition of HCF(II) as a predicted oxidation product did not considerably change the oxidation rates. Under the same experimental conditions, the oxidation rate of ampicillin was found to be slightly lower than that of flucloxacillin. The acquired oxidation products were recognized using spot testing and Fourier transform infrared spectra. A conceivable oxidation mechanism was suggested. A derived rate law expression was found to be consistent with the experimental results. The activation parameters were assessed and discussed.

The inhibition impacts of two water-soluble polymers viz., maltodextrin and chitosan on the dissolution of carbon steel in 1.0 M HCl solution were investigated by three dissimilar techniques. The investigation results indicated that the inhibition efficiencies of the examined polymers increased with their concentrations and reduced by raising temperature. The results obtained from polarization measurements proved that the investigated polymers act as mixed type inhibitors. The acquired high inhibition efficiencies of the studied polymers may be owing to powerful adsorption of the polymer molecules on the C-steel surface resulting in the construction of protective layers. Adsorption of the tested polymers on the steel surface was set to accord with Freundlich adsorption isotherm. The inhibition efficiency of chitosan was set to be higher than maltodextrin because of its high molecular mass that increases the surface area of steel covered by the polymer. The acquired thermodynamic parameters for adsorption indicated that the adsorption process is spontaneous and endothermic, and the type of adsorption is physical. The acquired outcomes from the dissimilar measurements were in a good agreement

The inhibitory strength of the two soluble polymer compounds namely, poloxamer (PLX) and pectin (PEC) towards the corrosion of carbon steel in 1.0 M HCl solution was elucidated utilizing four techniques. The inhibition efficacy augments with the concentration of the tested polymer and with reducing temperature. The outcome of the corrosion parameter obtained from all utilized measurements emphasizes the inhibiting vigor of these two compounds. The inhibition was interpreted by the formation of an adsorbing coated layer that isolates the steel surface from aggressive solutions. The adsorption of PLX and PEC on the steel surface follows Freundlich isotherm. The adsorption type is a combination of physical and chemical adsorption. Also, PLX and PEC compounds inhibit the pitting corrosion of Csteel in Clions including the solutions by moving the pitting potential in the positive direction. The inhibition efficacy of PET more than PLX due to higher molar mass of PET resulting in greater surface coverage on C-steel surface. There is a clear harmony on the values of the inhibition efficacy resulting from the different techniques.

The inhibition potentials of expired glibenclamide (Glib) and glimepiride (Glim) as two significant sulfonylurea antibiotic drugs on the corrosion behavior of mild steel in 0.5 M sulfuric acid solution were explored using different chemical and electrochemical ways. As the concentration of the expired drugs increases, the weight loss, corrosion current density and the capacity of double layer decrease while the values of charge transfer resistance, surface coverage and the percentage inhibition efficiency augment, indicating that the inhibitory impact of both expired Glib and Glim. The percentage inhibition efficiency increases with decrease in temperature. The inhibition was interpreted by the spontaneous adsorption of the two expired drugs on the mild steel surface by increasing the number of adsorbed particles that cover the largest area of the metal by constructing a barrier layer between the steel surface and the corrosive acid solution. The adsorption process is subject to Langmuir isotherm. Potentiodynamic polarization data demonstrate that both expired drugs act as mixed inhibitors. The activation and adsorption thermodynamic parameters were evaluated and suggest the physical adsorption of the examined drugs