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Traditional study has discovered that natural materials such as wood are scarce and that synthetic materials can serve as suitable substitutes. Polymer chemicals, plant materials, chemical compounds, inorganic compounds, and other corrosion inhibitors all use metals. When technology fails, corrosion is one of the most severe consequences, causing harm to the financial system, natural resources, and people's lives. Natural materials such as wood are scarce, according to traditional research, and synthetic materials may serve as suitable replacements. Polymers as corrosion inhibitors have piqued researchers' attention from both a theoretical and practical standpoint. It has been seen from the research that natural polymer inhibitors exhibits more than 90% efficiency and good surface cover on carbon steel surface. A summary of forms of corrosion, corrosion processes, and recent work on the application of polymer inhibitors on the basis of parameters such as cost, convenience of use, environmental impact, and reliability has been reviewed.

The present work focuses on developing Gd-doped Mn spinel nanoferrites and their potential application in the photodegradation of water pollutants. The impact of Gd

A series of carbon-doped solid solutions of ceria bismuth oxide (CBO) were prepared by a solid solution method. Highly porous solid solutions crystallized in a fluorite phase and C-doped samples exhibited an enhanced band-gap and reduced lattice cell constants. Their photocatalytic activity was observed in terms of H2 and O2 production via water splitting. The maximum hydrogen production was observed for a 6% C-doped solid solution in methanolic solution, i.e. 5413.10 mmol H2 g−1 h−1 under 300 W Xe light irradiation. The 6% C-doped solid solution released maximum O2 (193.80 μmol O2 h−1 g−1) and H2 (323.00 μmol H2 h−1 g−1) from pure water under exposure to real sunlight due to the highly ordered atomic arrangement, high porosity, high crystallinity, low oxygen vacancies, and high OH-group concentration in the lattice.

A series of quadruple perovskites Ca1+xCu3-xTi4O12 was scanned by different spectroscopic and microscopic techniques. X-ray powder diffraction pattern analysis revealed that the system transformed from a monophasic (x = 0.0, 0.1 and 0.2) to biphasic (x = 0.5 and 1.0) on Ca2+ - substitution. The completely different grain morphology and the distinct signature of the UV–visible absorption band and Raman scattering peak reflect this finding well. The defects arise mainly because of the mismatch between ion and site radii. The results of positron annihilation spectroscopy to study the nature of the defects are consistent with the proposed defect-rich sample history. There are many vacancies-type defects, whose size and concentration could be characterized through the measured positron lifetimes and coincidence Doppler broadening. The results show that for x = 0.1 itself, a secondary phase may be formed. The structure-property and property-property correlations are studied.

Polycrystalline ceramic sample of novel lead manganese silicate (Pb2Mn2Si2O9: Kentrolite) was prepared by solid state reaction at 860°C. Structural, morphological, dielectric and magnetic properties of the prepared product were investigated using XRD, EDS & SEM, impedance spectroscopic and VSM techniques. Rietveld refinement of XRD and EDS & SEM analysis confirmed that stoichiometric Pb2Mn2Si2O9 crystallizes in the orthorhombic structure (space group P21221, No.: 18). Frequency dependence of impedance and optical absorption studies establishes semiconducting nature of Pb2Mn2Si2O9. Dispersion in the dielectric parameters is observed due to hopping of electrons between Mn3+↔Mn2+ and Pb2+↔Pb3+. Pb2Mn2Si2O9 displays paramagnetic character at 300K and, it undergoes multiple magnetic transitions at TN = ~67K and TG = ~17K. This compound exhibits Curie-Weiss (θP) = −70K and the best fitted μeff = 3.76μB/Mn ion shows close agreement with the magnetic moment of free Mn3+ ion. Further, this study unveils co-existence of in plane ferromagnetic order (high coercivity = ~1000Oe and low retentivity = ~0.05emu/g) and long range antiferromagnetic order in Pb2Mn2Si2O9 at low temperatures.

In this study, Zn1-xLixO (x = 0.02, 0.04, 0.06, 0.08 and 0.10) nanohexagons were prepared by sol-gel combustion route and characterized using standard techniques for understanding their crystallography, surface morphology, optical, photoluminescence and magnetic properties. Single phase wurtzite type hexagonal crystal structure of the synthesized Li doped ZnO nanoparticles was identified from the Rietveld profile refinement of the powder XRD patterns and HRTEM & SAED analysis. HRTEM micrographs and XRD peak profile analysis confirmed formation of highly crystalline Li doped ZnO nanohexagons (ZnO:Li NHs) with average crystallite size in the 20–40nm range. Formation of functional Zn(Li)–O bonds in ZnO:Li NHs was confirmed by FTIR. SEM micrographs of the prepared samples showed random shaped, uniform distribution and well dispersed grains of ZnO:Li NHs. All the ZnO:Li NHs absorbs significant light in the UV band and the band gap energy monotonically decreases with increasing Li concentration in ZnO:Li NHs. Photoluminescence spectra exhibited two characteristic emission bands in all the ZnO:Li NHs and the UV emission band showed red shifting with increasing Li concentration, which is ascertained with the optical absorbance spectrums. Visible band spectral analysis of the PL data revealed formation of neutral, mono, and divalent oxygen vacancies along with the other defects like Zn vacancy in the ZnO lattice by Li doping and synthesis mechanism. All the ZnO:Li NHs exhibited weak ferromagnetism at RT. Lattice defects and oxygen vacancies created by Li1+ ions in the host ZnO lattice play significant role in band gap narrowing, photoluminescence in orange-red region and weak ferromagnetic ordering in ZnO:Li NHs.

The current research focuses on the photocatalytic, sonocatalytic and sonophotocatalytic degradation of nigrosine dye with nitrogen-doped and undoped zinc oxide powders. The sonophotocatalytic degradation of dye was found to occur at a higher rate than during photo- or sonocatalytic processes. Nitrogen-doped and undoped zinc oxide powders were synthesized by a wet chemical method. Further, scanning electron microscopy (FESEM), electron dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV-VIS spectroscopy (UV-VIS) and transmission electron microscopy (TEM) were used for the characterization of N-doped ZnO. The kinetics of nigrosine degradation were also studied and the results indicated that the degradation kinetics of nigrosine followed the first-order kinetics. The rate constant and the percentage of degradation were found to be highest, 7.33 × 10−4 (s−1) and 92% respectively, for sonophotocatalytic process after 90 min of reaction. Due to an increase in the available surface area or active sites of the catalyst, a higher rate constant and degradation efficiency was observed in the sonophotocatalytic system than in the photocatalysis system.

Nanoparticles of pure ZnO and monovalent, divalent & trivalent doped Zn0.96T0.04O (T: Li+, Ca2+& Gd3+) were prepared by the nitrate-citrate based sol-gel method. Powder XRD, TEM and photoluminescence data analysis confirmed single phase formation of pure ZnO, Zn0.96Li0.04O, Zn0.96Ca0.04O and Zn0.96Gd0.04O nanocrystals in the wurtzite type hexagonal lattice with surface and intrinsic crystal defects. UV–Vis–NIR optical absorption measurement demonstrated significant optical light absorption in the visible and UV bands for all the samples. A photo absorption peak below 380 nm is observed in all the four samples. The band gap energies were estimated to be 3.03eV, 2.78eV, 2.90eV and 2.79eV for ZnO, Zn0.96Li0.04O, Zn0.96Ca0.04O and Zn0.96Gd0.04O respectively. Monovalent and trivalent doping in ZnO induces reduction in the band gap energy and increment in the refractive index. 325 nm excited photoluminescence spectrums of pure and doped ZnO samples displayed a peak in the UV region and a broad peak in the visible band. Ca, Li and Gd doping in ZnO leads to red shifting of the UV emission band by substantial decrement in the band-gaps. Deconvoluted PL data analysis attests presence of various types of defects in the ZnO lattice which leads to strong electronic emission in the visible band. Computed values of CCT were found to be below 4000 K in these nanocrystalline samples, which makes them suitable material for the household optoelectronic devices. This study suggests that monovalent (Li+) doping in ZnO is better choice for tuning the optical and photoluminescence properties for their possible utilization in light harvesting and energy conversion applications.

This article describes synthesis of superparamagnetic fcc-CaFe2O4 nanoparticles by a metal nitrate-citrate monohydrate sol–gel route and characterization using X-ray diffractometry, Raman spectroscopic, UV–Vis–NIR optical absorption spectroscopic, Mossbauer spectroscopy, dielectric and SQUID magnetometry measurements. Rietveld refinement of the X-ray diffraction pattern and observation of active A1 g, T2 g & Eg modes in the Raman spectrum confirmed formation of single phase CaFe2O4 nanoparticles in the spinel ferrite type fcc structure without impurity. Mossbauer and Rietveld data analysis revealed that nanocrystalline CaFe2O4 is dominantly an inverse ferrite in which 85% Ca atoms preferentially occupy the octahedral site in the fcc symmetry and the Fe ions are in high spin Fe+3 state. Nanocrystalline CaFe2O4 significantly absorbs optical light below 500 nm and the direct band gap energy is estimated to ~1.83 eV, which is higher than 1.26 eV reported for orthorhombic CaFe2O4. Temperature and field dependent magnetic studies showed that fcc-CaFe2O4 nanoparticles exhibit superparamagnetism at room temperature with high saturation magnetization of 1.07μB. The blocking temperature is ~53 K at 1000 Oe and ~72 K at 500 Oe clearly shows lowering of blocking temperature at higher magnetic field. Interestingly below the blocking temperature at 20 K, CaFe2O4 nanoparticles behave as non collinear soft-ferrimagnetic material with a saturation magnetization of 1.16 μB, coercivity of 150 Oe and remanence of 4.45 emu/g. The magnetic momenta of Fe+3 ions residing at the octahedral sub-lattice are canted at ~25 °.

Cefotaxime sodium is applied in various concentrations in 0.5M sulphuric acid towards the mild steel and analyzed through weight loss, potentiodynamic polarization and EIS studies at 298 to 338oK. It gives good inhibition activity at lower temperature. Activation parameters, Gibbs free energy, Enthalpy and entropy of the reaction has been calculated and found that the inhibition process follows physical adsorption on the surface. Adsorption process follows langmuir’s adsorption isotherm. The inhibition behavior on mild steel surface is supplemented by the surface study through atomic force microscopy and found that the inhibited surface have less roughness than the uninhibited surface.

The author has focused on the corrosive effect of 0.14% carbon steel in the occurrence of several amounts of soluble Sulfonated Polystyrene (SPS) and was found to be best efficient on soft iron exterior at 100ppm concentration in 0.5M hydrochloric acid assortment at 298K heat during 3h of time in this paper. The examination was performed by studying the weight loss of mild steel by varying different parameters like mixture concentration, time, and solution temperature. The efficiency of SPS was observed to rise with an increase of 91.90% of an inhibitor in the acid solution. The mechanism of physical adsorption was studied to the initiation and permitted dynamics for the reaction of altitude and extracted taking place towards the exterior of the iron sample in endothermic, impulsive and dependable through the Langmuir isotherm adsorption. Anodic and cathodic both type of nature of soluble SPS was studied using the potentiodynamic polarization method. The AFM analysis was used to do the surface and protective film analysis and under varied settings, SPS polymer inhibitor proven to be more suited for iron metal exterior.

Polymers lead to become emerging materials as corrosion inhibitors for mild steel in acidic media due to its larger surface area. This paper focuses on the characteristic of water solvent Polyvinyl Alcohol (PVA) at interface of Mild Steel under 0.5 M HCl, examined using electrochemical impedance spectroscopy, Tafel polarization and weight reduction techniques. These entire outcomes of the study of characteristic of inhibitor behaved as in well connection and the restraint proficiency, which shows up to 93.7% in 0.5 M hydrochloric acid for 3hrs term. An advanced form of high spatial resolution imaging of surface of mild steel at different stages was found by using scanning electron microscopy.

Impact of hydrogenation on the structural, dielectric and magnetic properties of half-doped La0.5Ca0.5MnO3 manganate have been investigated. Polycrystalline sample of La0.5Ca0.5MnO3 was prepared through solid state reaction at ~ 1300 °C. Subsequently, the prepared sample was annealed at 600 °C for 6 h in a continuous flow of hydrogen gas in a tubular reduction furnace. Single-phase orthorhombic structure of the hydrogenated La0.5Ca0.5MnO3 in the space group Pnma was confirmed by Rietveld refinement of PXRD and FTIR analysis. SEM micrographs revealed well resolved grains of ~ 2 μm in a good crystalline sample. Hydrogenated La0.5Ca0.5MnO3 showed a sharp optical absorption peak in the UV range with a bandgap energy of 4.96 eV. Hydrogenation of La0.5Ca0.5MnO3 leads to significant reduction in the magnitude of dielectric constant and tangent loss at room temperature. Paramagnetic character of La0.5Ca0.5MnO3 at 300 K is retained upon the hydrogenation but the low temperature magnetic properties get modified dramatically. Temperature and field dependent magnetization measurements showed that hydrogenated La0.5Ca0.5MnO3 undergoes paramagnetic to antiferromagnetic transition at TN = ~ 110 K and in a disordered magnetic phase below 50 K. Systematic enhancements in the magnitude of saturation magnetization (Ms), coercivity (Hc), remanence (Mr) and squareness ratio at 50 K and 20 K indicate for the coexistence of antiferromagnetic and weak ferromagnetic order due to competitive magnetic exchange interactions between Mn3+ and Mn4+ ions. This study shows that hydrogenation plays key role in the modification of dielectric and magnetic properties of La0.5Ca0.5MnO3.

This article presents an in-depth study on the structural, morphological, electrical and magnetic characterizations of two new phases of apatite-type lanthanide silicates. Polycrystalline samples of neodymium and samarium–manganese silicates (Nd4MnSi3O13 and Sm4MnSi3O13) were synthesized using a high-temperature solid-state reaction route. Rietveld profile refinement of X-ray diffraction data and FTIR analysis revealed that Nd4MnSi3O13 and Sm4MnSi3O13 crystallize in the single-phase apatite-type hexagonal structure with P63/m space group. Scanning electron micrographs showed good crystallinity in the two silicate samples, and the average size of the grains is found to be in submicrons. Frequency dependence of dielectric constant and tanδ for Nd4MnSi3O13 and Sm4MnSi3O13 showed systematic decrement with frequency. DC conductivity studies are indicative of low activation energy and semiconducting nature of Nd4MnSi3O13 and Sm4MnSi3O13. At room temperature, both the silicates exhibit dominant paramagnetism; however, short-range one-dimensional ferromagnetic chains coexist in the paramagnetic state of Nd4MnSi3O13 and Sm4MnSi3O13.