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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.