Abstract: In the current study, Bi2/3Cu3Ti4O12 (BCTO) ceramics were prepared by mechanical
ball mill of the elemental oxides followed by conventional sintering of the powder without any
pre-sintering heat treatments. The sintering temperature was in the range 950–990 C, which is
100–150 C lower than the previous conventional sintering studies on BCTO ceramics. All the ceramic
samples showed body-centered cubic phase and grain size  2–6 m. Sintering temperature in the
range 950–975 C resulted in comparatively lower dielectric loss and lower thermal coefficient of
permittivity in the temperature range from ?50 to 120 C. All the BCTO ceramics showed reasonably
high relative permittivity. The behavior of BCTO ceramics was correlated with the change in
oxygen content in the samples with sintering temperature. This interpretation was supported by the
measurements of the energy dispersive x-ray spectroscopy (EDS) elemental analysis and activation
energy for conduction and for relaxation in the ceramics.

Abstract: (Nb5+, Si4+) co-doped TiO2 (NSTO) ceramics with the compositions (Nb0.5Si0.5)xTi1?xO2,
x = 0, 0.025, 0.050 and 0.1 were prepared with a solid-state reaction technique. X-ray diffraction
(XRD) patterns and Raman spectra confirmed that the tetragonal rutile is the main phase in all the
ceramics. Additionally, XRD revealed the presence of a secondary phase of SiO2 in the co-doped
ceramics. Impedance spectroscopy analysis showed two contributions, which correspond to the
responses of grain and grain-boundary. All the (Nb, Si) co-doped TiO2 showed improved dielectric
performance in the high frequency range (>103 Hz). The sample (Nb0.5Si0.5)0.025Ti0.975O2 showed the
best dielectric performance in terms of higher relative permittivity (5.5  104) and lower dielectric
loss (0.18), at 10 kHz and 300 K, compared to pure TiO2 (1.1  103, 0.34). The colossal permittivity
of NSTO ceramics is attributed to an internal barrier layer capacitance (IBLC) effect, formed by
insulating grain-boundaries and semiconductor grains in the ceramics.

Abstract: Herein we have fabricated AuTiO2 from a one-dimensional (1D) nanocomposite by the
simple oxidation method of the Ti sheet for supercapacitor applications. We intended on fabricating a
microlayer extended into the sheet body to form a selfstanding electrode. Raman spectra and XRD
patterns confirmed the formation of the rutile phase of the TiO2 bulk, and FESEM confirmed the
growth of the 1D nanostructure made of Au/TiO2, where the Au nanoparticles reside on the tip of
the TiO2 nanorods. The growth of 1D TiO2 by this method is supported by a growth mechanism
during the oxidation process. Three electrodes were fabricated based on pure and doped TiO2. These
electrodes were used as a selfstanding supercapacitor electrode. The Au-doped TiO2 exhibited a great
improvement in the electrochemical performance at low Au concentrations, whereas the excessive Au
concentration on the TiO2 surface exhibited a negative effect on the capacitance value. The highest
areal capacitance of 72 mFcm?2 at a current density of 5 Acm?2 was recorded for TiO2 doped with
a low Au concentration. The mechanism of the electrochemical reaction was proposed based on
Nyquist and Bode plots. The obtained results point out that the effect of Au on the TiO2 surface
makes Au/TiO2 ceramic electrodes a promising material as selfstanding energy storage electrodes.

Abstract: Controlling of morphology from nanoparticles to magnetic nanotubes and hollow nanorods
are interesting for developing the photo-active materials and their applications in the field of photocatalysis
and decontamination of aquatic effluents. In the current study, titanium dioxide nanoparticles
and nanocomposites were prepared by different techniques to produce various morphologies.
The nanoparticles of pure titanium dioxide were prepared by sol-gel technique. Magnetic nanotubes
and hollow nanorods were prepared by combining titanium with di- and tri-valent iron through two
stages: urea hydrolysis and solvent thermal technique. According to the Kirkendall effect, magnetic
nanotubes were fabricated by unequal diffusion of Fe2+, Fe3+ and Ti4+ inside the nanocomposite
to produce maghemite-titanian phase. In the same trend, hollow nanorods were synthesized by
limited diffusion of both trivalent iron and tetravalent titanium producing amorphous structure of
titanium iron oxides. The magnetic and optical properties showed that these nanotubes and hollow
nanorods are magnetically active and optically more effective compared with titanium dioxide
nanoparticles. Therefore, the Naphthol green B dye completely disappeared after 45 min of UV light
irradiation in presence of the hollow nanorods. The kinetic study confirmed the high performance of
the hollow nanorods for the photocatalytic degradation of Naphthol green B compared with titanium
dioxide nanoparticles.

The mechanism of oxidative removal of flucloxacillin antibiotic (Flx) by two different oxidants (Ox), potassium bromate (KBrO3) and potassium iodate (KIO3), were studied using a spectrophotometric technique in sulfuric acid medium. The stoichiometry of the oxidation reactions of flucloxacillin by both oxidants was set to be a 2: 3 (Ox: Flx). The oxidation products of flucloxacillin were identified utilizing spot tests and FT-IR spectroscopy. The reactions followed a first order credence in [Flx] and lesser than unit order kinetics regarding to both [Ox] and [H+]. Negligible impacts of both ionic strength and dielectric constant of the reactions medium on the rates of reactions were observed. The dependence of the oxidation rates on mercuric acetate concentration which works as a scavenger for any bromide or iodide ion composed during the reactions was investigated. Credence of reaction rates on temperature was studied, and the activation parameters were assessed and discussed. Tests for free radicals involvement throughout the oxidation reactions were negative. The reactions mechanism was elucidated and the rate law expressions were derived.

The inhibition impacts of three synthesized propane bis-oxoindoline derivatives on the mild steel corrosion behavior in 1.0 M solution of sulfuric acid was explored using weight loss (WL), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), as well as the scanning electron microscopy (SEM) techniques. The outcomes of WL measurements displayed that the inhibition efficiencies of the tested propane bis-oxoindoline derivatives enhanced with their concentrations and reduced with rising temperature. The maximum inhibition efficiency was set to be 93 % at 288 K. PDP study revealed that the synthesizedorganic compounds act as mixed-type inhibitors with a predominant anodic type. The synergistic inhibition impact amongst the examined inhibitors and certain divalent transition metal ions followed the order: Zn2+> Co2+> Cd2+. It has been found that adsorption of bis-oxoindoline inhibitors on the steel surface are compatible with Langmuir adsorption coefficient, and the calculated thermodynamic parameters supported the physical nature of the adsorption process. The assessed activation energy for mild steel dissolution in H2SO4 was noticed to rise from 6.32 kJ mol−1 in the uninhibited medium to (24.53 – 32.59) kJ mol−1 in the presence of a 500 ppm of the examined organic compoundsconfirming strong adsorption of the inhibitor molecules, thus reducing the corrosion rates. The mechanism of corrosion of mild steel in H2SO4solution and its inhibition in the existence of the synthesized organic inhibitors were discussed. The acquired outcomes from all employed techniques were in a good accordance

Kinetics and mechanism of oxidation of two biologically reactive heterocyclic compounds, namely, barbituric (BA) and thiobarbituric (TBA) acids by chromium trioxide (CrVI) have been explored using UV–Vis absorption spectra in sulfuric and perchloric acid solutions at fixed ionic strength of 2.0 mol dm−3 and a temperature of 298 K. The oxidation reactions demonstrated a 3:4 stoichiometry (organic acid: CrVI). The reactions kinetics in the examined acidic media were set to be first order with admiration to [CrVI] and fractional orders in organic acid and H+ concentrations. Varying the ionic strengths and dielectric constants of the reaction media had no noteworthy influence on the reactions’ rates. Tests for free radicals involvement throughout the reactions were positive. Addition of chromium(III) as a predicted oxidation product did not considerably alter the rates whereas addition of manganese(II) diminished the oxidation rates. Supplementation of some divalent transition metal ions increased the oxidation rates. At same investigational circumstance, the rates of BA oxidation in both acidic media were set to be about 20–30% higher than those of TBA, and those acquired in sulfuric acid were also found to be higher than those of perchloric acid solutions for both BA and TBA with almost the same percentages. The oxidation products of BA and TBA were described as 2,4,5,6-pyrimidinetetraone (alloxan) and 2-thio-4,5,6-pyrimidinetrione, respectively. A conceivable oxidation mechanism has been anticipated. The derived rate-law expression was in a good agreement with the investigational outcomes. The activation parameters with regard to the second order rate constants were assessed and debated. The existing study presents an unprecedented simple and inexpensive treatment method for removal of certain pollutants for saving the environment and human health.

In this report, two chromotrope dyes, chromotropic acid (CA) and chromotrope 2R (CR), were explored as inhibitors against mild steel corrosion in 1.0 M sulfuric acid solutions at 303 K. Electrochemical, spectroscopic, chemical, and microscopic techniques, namely, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy, mass loss, and scanning electron microscopy (SEM), have been employed to evaluate the inhibition efficiencies (%IEs) of the examined organic dyes. The %IEs were found to increase with the inhibitors’ concentrations, while they decreased with rising temperature. The outcomes of the PDP technique displayed that the examined inhibitors operated as mixed-type inhibitors with anodic prevalence. The impedance spectra described by Nyquist and Bode graphs in the corrosive environment and in the presence of various concentrations of the examined inhibitors showed single depressed capacitive loops and one-time constants. This behavior signified that the mild steel corrosion was managed by the charge transfer process. The SEM micrographs of the surfaces of mild steel samples after adding the examined inhibitors revealed a wide coverage of these compounds on the steel surfaces. Thus, the acquired high %IEs of the examined inhibitors were interpreted by strong adsorption of the organic molecules on the mild steel surface. This constructed a shielding layer separating the alloy surface from the corrosive medium, and such adsorption was found to follow the Langmuir isotherm. Furthermore, the evaluated thermodynamic and kinetic parameters supported that the nature of such adsorption was mainly physical. Results obtained from all employed techniques were consistent with each other and revealed that the %IE of the CR inhibitor was slightly higher than that of CA under similar circumstances. Finally, the mechanisms of both corrosion of mild steel in sulfuric acid solutions and its inhibition by the tested organic dyes were also discussed.

Expired antibacterial drugs such as ampicillin (AMP) and Ceftriaxone (CRO) were used as anticorrosive for Sabic Fe corrosion in 1.0 M HCl solutions. Chemical and electrochemical methods were applied to confirm the performance of the inhibition of these drugs. The effectiveness of inhibition increases with an increased concentration of AMP and CRO drugs which also decreases with temperature. The inhibition performance of drugs owing to their adsorption on the Sabic iron surface through the Langmuir adsorption isotherm. Galvanostatic polarization demonstrated that the expired AMP and CRO act as mixed inhibitors. The thermodynamic function for activation and adsorption process was defined and interpreted. AMP and CRO drugs inhibit the pitting attack caused by the presence of chloride ions. Pitting potentials were transferred to more noble values that demonstrated that these drugs served as pitting corrosion inhibitors. All outcomes findings confirm that the AMP and CRO acted as excellent inhibitors for Sabic Fe corrosion in 1.0 M HCl solutions and the CRO is more efficient inhibitors than AMP at all the studied concentrations owing to its high molar mass. The quantum chemical calculations of the expired AMP and CRO drug molecules were done and discussed using density functional theory (DFT) method. The quantum chemical calculations and the results of the molecular dynamics simulation correlate well with experimental observations.

The inhibition impacts of two novel synthesized green biosurfactants (B-Surf.), namely, sodium Ndodecyl asparagine (AsS) and sodium N-dodecyl arginine (ArS), on the dissolution of mild steel alloy (MS-37-2), in aqueous sodium chloride solutions was inspected using various techniques. Increased concentration of NaCl solution resulted in an increase in the corrosion rate of MS-37- 2. Inhibition efficiencies of B-Surf. compounds were found to increased with increase inhibitor concentrations. The synergistic inhibition action between B-Surf. inhibitors and Zn2+, Al3+ and Ce4+ on the dissolution behavior of steel alloy in NaCl solutions was investigated and interpreted. The surface morphology of the MS-37-2 surface was observed using a scanning electron microscopy (SEM). This adsorption follows Langmuir isotherm. The evaluated thermodynamic functions supported the mechanism of physical adsorption of the inhibitors. The mechanisms of corrosion and its inhibition of MS-37-2 in NaCl solutions were interpreted.