Rare-earth metal oxide nanomaterials have emerged as versatile multifunctional platforms owing to their unique electronic configurations, defect tolerance, and remarkable optical, magnetic, and electrical properties. Unlike conventional single-function nanomaterials, rare-earth oxides offer integrated structural and electronic tunability, where nanoscale parameters such as particle size, morphology, exposed crystal facets, and A- and B-site rare-earth doping systematically influence defect chemistry, lattice strain, and the local electronic environment. Controlled synthesis approaches encompassing chemical, electrochemical, biological, and other advanced methods play a decisive role in tailoring structure–property relationships and optimizing functional performance. These coordinated structural and electronic characteristics enable broad multifunctional applications across diverse technological sectors. In biomedicine, rare-earth oxides enable drug and gene delivery, cancer therapy, tissue engineering, antimicrobial activity, and high-contrast bioimaging due to their chemical stability, surface functionality, and tunable luminescence. In environmental remediation, they support efficient catalysis, selective adsorption, and sensitive gas sensing for pollution control and environmental monitoring. In energy technologies, their redox flexibility, oxygen vacancy dynamics, and coupled ionic–electronic transport properties enhance performance in supercapacitors, batteries, fuel cells, electrocatalysis, and electrochemical sensors. Furthermore, their structural robustness and radiation-resistant characteristics make them promising candidates for nano-shield systems designed for radiation protection and electromagnetic interference shielding under extreme conditions. Despite substantial progress, key challenges remain in achieving precise atomic-level structural control, scalable and sustainable synthesis, comprehensive mechanistic understanding of defect-mediated processes, and long-term operational stability, all of which are essential for translating rare-earth oxide nanomaterials into reliable, high-performance multifunctional technologies.

Magnesium oxide (MgO) nanoparticles are potential wide band gap materials for use in catalysis, optoelectronics, sensors and dielectric devices due to their high thermal constancy, chemical inertness, and defect-dependent optical characteristics. The present study uses an integrated experimental and first principles technique to examine the structural, morphological, optical and electrical aspects of MgO nanoparticles. The structural and optical properties of the nanoparticles were systematically investigated using XRD, FTIR and UV-Vis Spectroscopy. The crystallite size was calculated as 15.38 nm, and the band gaps obtained experimentally (4.9 eV) and through Density Functional Theory (DFT) calculations (4.7 eV) shows strong consistency. To complement the experimental analysis, computational modelling was performed using the Quantum ESPRESSO software package, with graphical interface support provided by the BURAI visualization tool. The band gap of MgO was determined using both experimental and theoretical approaches. Furthermore, electronic properties such as band structure, DOS, Fermi level, and VBM–CBM were investigated in detail. The combined experimental and computational analyses provided deep insight into the material’s electronic nature, and symmetry. The results revealed distinct features of MgO nanomaterials and confirmed the consistency between theoretical predictions and experimental findings. The integrated experimental- DFT approach provide a trustworthy knowledge of the structure-property connection in MgO nanoparticles and supports their promise for advanced optical and electrical applications. Not applicable.

Al 2 O 3 exists in several polymorphs (γ, δ, θ, etc.), which progressively transform into the thermodynamically stable α-phase at elevated temperatures. In the present work, Al 2 O 3 nanoparticles were synthesized via the SCS route and subsequently annealed at 500, 700, 900, and 1200°C to induce controlled phase transformations. XRD confirmed the sequential γ → δ→ α transitions with increasing annealing temperature. FTIR verified the evolution of Al-O vibrational modes, while SEM revealed distinct and smooth structures in the α-phase. EDX confirmed compositional purity, UV-Vis absorbance and reflectance analyses showed band gap widening and a reduction of defect states, while PL spectra demonstrated the disappearance of defect related emissions and the emergence of α-phase specific features. The correlation of structural, morphological and optical studies with XRD establishes a comprehensive understanding of the γ → δ→ α transformations in Al 2 O 3, providing valuable insights into tailoring alumina phases for advanced functional applications.

Magnesium oxide (MgO) is a wide band-gap ceramic dielectric material with significant potential in various industrial and technological applications. In this study, MgO nanoparticles were synthesized using the Solution Combustion Synthesis (SCS) method. The structural properties of the synthesized nanoparticles were analysed using X-ray Diffraction (XRD) from which average crystallite size, calculated using the Scherrer equation, was found to be 24.76 +/- 2.11 nm. Williamson-Hall (W-H) analysis was employed to determine the crystallite size, microstrain, and residual stress. The Texture Coefficient (TC) was also evaluated to quantify the preferred orientation of crystal planes. Morphological studies done using Scanning Electron Microscopy (SEM) revealed a highly porous surface morphology with irregularly shaped, agglomerated particles. Transmission Electron Microscopy (TEM) showed that the nanoparticles were predominantly spherical, with some slightly faceted structures. Fourier Transform Infrared Spectroscopy (FTIR) identified strong physical adsorption bands corresponding to HQO and COQ, indicating ultrafine particle behaviour. Optical properties were studied using UV-Vis spectroscopy. Band gap values obtained from both the Tauc plot (4.92 eV) and the Kubelka-Munk function (4.88 eV) were found to be comparable.

In recent times, the rapid development of industries has led to the discharge of enormous amounts of pollutants, including hazardous dyes, and environmental toxicants into water sources, thereby posing potential threats to human health and the environment. This work presents the synthesis of cerium oxide nanoparticles by solution combustion technique and its application as an efficient photocatalyst for the removal of harmful industrial effluents, as a reducing agent for the photochemical reduction of Cr(VI) to Cr(III) and also, as high performance antibacterial activity agent. The synthesised cerium oxide nanoparticles was characterised using TGA, XRD, FESEM, EDAX, FTIR, FT-Raman, UV-Visible absorbance, and reflectance spectroscopic techniques. The synthesized cerium oxide nanoparticles exhibited strong UV-Visible absorbance and showed excellent photocatalytic efficiency under sunlight illumination. The synthesized catalyst demonstrated significant photocatalytic degradation efficiency, achieving removal rates of 17.37%, 36.25%, 12.77% and 81.93 % respectively for Congo red, Malachite Green, Rhodamine B and Crystal Violet after 240 min of sun light irradiation. Due to the high level of photodegradation rate when compared to other dyes, Crystal Violet dye was selected for further degradation studies. The influence of operational parameters such as photocatalyst concentrations, dye concentrations, pH of reaction along with its reusability and, the radical trapping experiments were studied. As a reducing agent, CeO2 nanoparticles performed the photochemical reduction of the environmental toxicant, Cr(VI) to Cr (III), achieving an adsorption efficiency of approximately 82.2 % at a concentration of 0.001 M. As an antimicrobial agent, the synthesized CeO2 nanoparticles exhibited strong antibacterial activity against Gram-positive bacteria Staphylococcus aureus, Bacillus paramycoides and Gram-negative Escherichia coli, with inhibitory zone diameters of 28 mm, 20 mm, and 20 mm, respectively.

In this study, density functional theory (DFT) calculations are carried out using Gaussian 16, which are employed to explore the interactions between environmentally significant toxic gas molecules methane (CH4), carbon dioxide (CO2) and ammonia (NH3) and its adsorption on silver nanoclusters (Ag3). These interactions are investigated to understand their potential applications in pollutant detection and environmental monitoring. The structural and electronic properties Ag3-X (X = CH₄, CO₂, NH₃) complexes are optimized and analysed through molecular orbital calculations, including HOMO–LUMO gaps, band gaps, and molecular electrostatic potential (MEP) maps. Key thermodynamic parameters such as binding energy, free energy, and adsorption energies are calculated to evaluate adsorption efficiency. The study also examines vibrational properties via surface-enhanced Raman scattering (SERS), providing detailed Raman spectra that highlight shifts in frequency and intensity upon gas adsorption, which helps in predicting the stability of the analyte-Ag cluster composite. The results demonstrate the utility of silver nanoclusters as sensitive, selective platforms for detecting trace levels of atmospheric pollutants. This computational approach underscores the value of hybrid DFT methods in designing sustainable nanomaterials for real-time environmental sensing applications.

In this study MgO nanoparticles were synthesized using the SCS methods followed by annealing at 700°C to enhance crystallinity and phase stability. The structural and optical properties of the nanoparticles were systematically investigated using XRD, FTIR and UV-Vis Spectroscopy. To complement the experimental analysis, computational modelling was performed using the Quantum ESPRESSO software package, with graphical interface support provided by the BURAI visualization tool. The band gap of MgO was determined using both experimental and theoretical approaches. Furthermore, electronic properties such as band structure, DOS, Fermi level, and HOMO–LUMO were investigated in detail. The combined experimental and computational analyses provided deep insight into the material’s electronic nature, and symmetry. The results revealed distinct features of MgO Nanomaterials and confirmed the consistency between theoretical predictions and experimental findings. This integrated approach not only advances our understanding of MgO but also establishes a robust framework for future studies involving doped systems.

The most widely used type of spinel aluminate is Cobalt Aluminate (CoAl2O4). This spinel is known to have different structural, magnetic and morphological characteristics depending upon their synthesis methods and the types of materials used. A variety of fine, complex oxide powders have been produced using the Solution Combustion Method (SC), which is employed for advanced applications such as catalysts, fuel cells and in biotechnology. In the current study, COAl2O4 nano-particles was prepared using the solution combustion technique. Various temperatures used to heat the samples at 500 °C, 700 °C and 900 °C in order to understand various properties of the materials with different annealing temperatures. Using XRD, SEM, EDAX and FT-IR the structural, morphological and compositional properties of the materials were analysed in this paper. XRD confirmed that the obtained metal oxides are COAl2O4 and these oxides crystalline sizes were calculated using Scherrer equation. Metal oxide structures were confirmed by FT-IR. On comparing the three samples, the sample annealed at 900 °C showed good UV–Vis absorption and also it proves to be a suitable choice for the degradation of organic dyes.

In the present study, NiAl 2 O 4 nanocomposite was synthesized using solution combustion method.The sample was annealed at three different temperatures (500C, 700C and 900C) to study the variations in properties attained with annealing temperature.Structural characterizations of all the synthesized samples were carried out using XRD, SEM, EDAX and FTIR analysis.From XRD, the formed metal oxides were confirmed to be NiO/NiAl 2 O 4 nanocomposite.Crystallite sizes of these oxides were calculated using Scherrer equation.FTIR also confirmed the structure of metal oxides.All three samples showed strong UV-Vis absorption that made them suitable candidate for photocatalytic degradation of organic dyes.The photocatalytic degradation activity of all three synthesized nanocomposites on acidic dye (Congo red) were studied and compared.Results confirm that proper tuning of these nanocomposites could improve their photocatalytic activity.У цьому дослідженні нанокомпозит NiAl 2 O 4 був синтезований за допомогою методу спалювання розчину.Зразок відпалювали за трьох різних температур (500C, 700C і 900C) для вивчення варіяцій властивостей, досягнутих за температури відпалу.Структурні характеризації всіх синтезованих зразків проводилися за допомогою рентґенівської дифракції, сканувальної електронної мікроскопії, енергорозсіювальної рентґеноспектральної електронно-зондової мікроаналізи й інфрачерво-Наносистеми, наноматеріали, нанотехнології Nanosistemi, Nanomateriali, Nanotehnologii 2022, т. 20, № 2, сс.459-472  2022 ІÌÔ (Іíñòèòóò ìåòàëîôіçèêè іì.Ã. Â. Êóðäþìîâà ÍÀÍ Óêðàїíи) Надруковано в Україні.460 Babu NANDANA, Devadathan DEDHILA, V

In the present work, zinc aluminate nanocomposite was synthesized through chemical oxidation method. Polyaniline was used as the base Here zinc aluminate was synthesized by Solution Combustion Synthesis (SCS) method and polyaniline by chemical oxidation method. .For comparative study, the counterparts were also synthesized. Structural studies were done using SEM, EDAX, XRD and FTIR. XRD confirmed the formation of nanocomposite. Crystallite sizes were calculated using Scherrer equation. Surface morphology of the samples revealed by SEM shows a widely varying morphology. Using EDAX chemical purity of metal oxide part was confirmed. EDAX of polyaniline and the nanocomposite showed that sulphur was present as dopants. FTIR confirmed the structure of metal oxide, polyaniline and zinc aluminate nanocomposite formed. In the case nanocomposite the presence of metal oxide in the polymer was confirmed. Optical characterization of the samples was done using UV–Vis spectroscopy and PL spectroscopy. The photocatalytic activity of zinc aluminate nanocomposite and its counterparts were investigated for the photo degradation of organic dye: Crystal violet. The variations in different experimental conditions such as effect of contact time, dye concentration and amount of photocatalyst that affects photocatalytic oxidation were also studied. Results suggested that the nanocomposite prepared in the present study is promising photocatalyst. Also, an increase in degradation efficiency was observed in the case of nanocomposite when compared to their counterparts. The counterparts also showed excellent results. Hence concluded that proper tuning can give an excellent photocatalyst for degradation of organic dye, Crystal Violet.

Zinc aluminate (ZnAl2O4) is a member of the spinel oxides having the general for AB2O4. It can be synthesized by many methods like co precipitation, sol-gel, combustion etc. Here the Solution Combustion Synthesis method is used for its synthesis, as it is simple, rapid and low cost method. The synthesized samples were annealed at four different temperatures. All the four samples were analyzed using XRD, SEM and FTIR. The result shows that annealing temperature affects the structure and morphology of the ZnAl2O4.

In the present study copper oxide and magnesium oxide nanoparticles were synthesized using solution combustion method. Both samples were annealed at 500°C and 700°C to study the variations in properties attained with annealing temperature. Structural characterizations of all the synthesized samples were carried out using XRD and FTIR analysis. From XRD the formed metal oxides were confirmed to be CuO and MgO. Crystallite sizes of these oxides were calculated using Scherrer equation. FTIR confirmed the structure of metal oxides. All the four samples prepared in this work showed strong UV absorption which makes them suitable for anti UV applications such as anti UV glass, anti UV sunscreen, etc. Copper oxide nanoparticles showed visible range absorption in addition to UV range. The antimicrobial activity of all the synthesized nanoparticles were studied and compared. The selected microbes were B. cereus and E.coli. The results varied considerably. The results indicate that both nano metal oxides effective against gram negative bacterial strains. Activity was found to be highest for E.coli. Proper tuning of the nanoparticles is expected to improve its antimicrobial activity.

In the present work, ZnO/MgO nanocomposite was synthesized using a co-precipitation method, polyindole and the polyindole based ZnO/MgO nanocomposite were synthesized using chemical oxidation method. The synthesized materials were characterized using XRD and UV/Vis absorbance spectroscopy. The study investigates the applicability of polyindole based ZnO/MgO nanocomposite for the removal of Pb(II) heavy metal ion. Proper tuning can increase the removal efficiency of polyindole based ZnO/MgO nanocomposite and can be made a good candidate for the removal of lead ions.

The present study is focused on the structural and antibacterial studies of rice straw based ZnO nanocomposite. For comparison, counterparts were also synthesized. Nanoparticles of ZnO were synthesized through combustion method and co-precipitation method. Structural characterizations of all the synthesized samples were carried out using XRD. Antibacterial studies of the synthesized samples were carried out. The present study investigates the antimicrobial activity of the synthesized samples as antibacterial agents. The selected microbes for the present study are gram-positive bacteria: Bacillus cereus (B. cereus), the gram-negative bacteria: Escherichia coli (E. coli)..

The present study is focused on the comparison of structural and optical properties of nanocomposite of Fe2O3 formed with both rice straw, a biopolymer and polyindole, a conducting polymer. For comparison, counter parts were also synthesized. Nanoparticles of iron oxide were synthesized through controlled co-precipitation method in presence of citric acid. Structural characterizations of all the synthesized samples were carried out using XRD. Comparison of XRD of metal oxide with JCPDS confirmed that the formed metal oxide was Fe2O3. Optical studies of all the samples were carried out using UV/Vis spectroscopy. From band gap calculation it was seen that all of them except polyindole showed subgaps. Also these samples were employed as photocatalyst in the photocatalytic degration study of organic acidic dye Congo Red. Results suggested that the nanocomposites prepared in the present study are promising photocatalysts. Also an increase in degradation efficiency was observed in the case of nanocomposites when compared to their counterparts.

The present study is focused on the comparison of structural and photocatalytic degradation activities of nanocomposite of MgO formed with rice straw, a biopolymer. For comparison, counter parts were also synthesized. Nanoparticles of magnesium oxide were synthesized through controlled co-precipitation method in presence of citric acid. Structural characterizations of all the synthesized samples were carried out using XRD. Comparison of XRD of metal oxide with JCPDS confirmed that the formed metal oxide was MgO. Photocatalytic degradation of organic dyes Congo Red, an acidic dye and Methylene Blue, a basic dye was done.

In the present work, polyindole based metal oxide nanocomposites were synthesised through chemical oxidation method. For comparative study, the counterparts, polyindole was synthesised through chemical oxidation method and the metal oxides were synthesised through chemical coprecipitation method. Structural studies were done using XRD. Phase purity and crystallinity of these samples were confirmed from XRD. XRD confirmed the formation of nanocomposites. Crystallite sizes were calculated using Scherrer equation for metal oxides. The present study investigates the antimicrobial activity of the synthesized samples as antibacterial agents. The gram positive bacteria: S. epidermidis and C. perfringens, gram negative bacteria: E. coli and V. cholera were the microbes used in the present study. The study confirms that the polyindole based metal oxide nanocomposites samples prepared in the present study showed antibacterial agent activity. The results suggest that proper tuning can make them good antimicrobial agents.

The aim of the present work was to synthesize polyindole based NiO-MgO nanocomposite, to study the factors affecting photocatalytic process and also to find out the optimal conditions that could be used in this process. The synthesized material was characterized using SEM, EDAX and XRD. The study also investigates the applicability of the nanocomposite as an antimicrobial agent.

In this study single salts of nickel oxide, cobalt oxide, ferric oxide and the nanocomposite of nickel-cobalt-ferric oxide was prepared by the well-known co-precipitation method. The samples were annealed at different temperatures and were characterized using SEM, EDAX, TGA, FTIR, XRD, UV and Photo luminescence (PL). UV analysis showed that the nanocomposite can be suitably tuned to a wide band gap material. The Photo Luminescence analysis showed that the nanocomposite can be used as light emitters in visible region.