In pursuit of multifunctional materials for sustainable energy and environmental applications, this study reports the synthesis and characterization of Dy-Ce co-substituted barium hexaferrites (BaDyxCexFe12-2xO19) using the sol-gel auto-combustion method. This approach enables the formation of nanostructured particles with high phase purity and controlled morphology. Comprehensive analyses including X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, and electrochemical evaluations demonstrate that rare-earth doping introduces oxygen vacancies and lattice distortions, thereby enhancing redox activity and electrical conductivity. The optimized composition (x = 0.02) exhibits a high specific capacitance of 847.21 F/g at a scan rate of 10 mV/s, ascribed to improved pseudocapacitive behavior and defect-mediated charge transport. Hydroelectric cell performance for the same composition yields a maximum open-circuit voltage of 1.05 V and a short-circuit current of 30 mA, validating the role of defect-engineered surfaces in promoting efficient water dissociation and ionic conductivity. Additionally, the photocatalytic degradation of methylene blue (10 ppm) under solar irradiation achieves a degradation efficiency of 83.1% within 200 min at neutral pH, underscoring the material's utility for environmental remediation. The synergistic effects of Dy3+ and Ce4+ co-doping via mixed valence states, ionic size disparities, and resultant oxygen vacancy formation collectively contribute to superior electrochemical and photocatalytic properties. These findings establish Dy-Ce substituted BaFe12O19 hexaferrites as promising candidates for integrated energy storage, hydroelectric power generation, and wastewater treatment systems.

Nanoparticles of Dy–Ce co-substituted M-type strontium hexaferrite with the general formula SrDyxCexFe12-2xO19 (x = 0.00–0.10) were synthesized by sol–gel auto-combustion method. X-ray diffraction (XRD) confirmed the formation of the hexagonal magnetoplumbite phase (space group P63/mmc) with a minor α-Fe2O3 impurity at intermediate substitution levels. Raman spectroscopy confirmed the formation of the magnetoplumbite hexagonal structure and indicated structural modifications induced by Dy–Ce co-substitution, and X-ray photoelectron spectroscopy (XPS) confirmed the presence of Fe3+/Fe2+, Ce3+/Ce4+, Dy3+ and lattice oxygen with oxygen vacancies, FE-SEM and HR-TEM studies identified the hexagonal plate-like nanostructures with improved grain homogeneity for x = 0.04, while EDS confirmed the successful doping of Dy and Ce without any impurity elements. The BET analysis showed a maximum specific surface area of 15.06 m2 g −1 for the x = 0.04 composition, which showed the enhancement of mesoporosity as a result of rare-earth substitution. Electrochemical measurements indicated that the maximum specific capacitance of the x = 0.04 sample was 983.8 F g−1 from cyclic voltammetry at 10 mV s−1 and 510.6 F g−1 from galvanostatic charge–discharge at 1 mA g−1 with 87% capacitance retention after 5000 charge–discharge cycles. Electrochemical impedance spectroscopy revealed reduced charge-transfer resistance and accelerated ion transport upon rare-earth substitution. The best photocatalytic performance was observed for the composition of x = 0.10 with 91.6% degradation of malachite green dye under solar irradiation and a first order rate constant of 0.01104 min−1. The results reveal that the Dy–Ce co-substitution is advantageous to the structural, electrochemical, and photocatalytic properties of the M-type strontium hexaferrite.

A novel soft-hard ferrite nanocomposite system composed of Ni0.55Cu0.2Zn0.25Fe2O4 (NCZFO) and SrFe12O19 (SFO) was synthesized for supercapacitor and hydroelectric cell (HEC) applications using physical mixing and one-pot sol-gel auto-combustion methods. XRD with Rietveld refinement confirmed high phase purity, while Raman and FTIR analyses revealed strong interfacial interactions between the ferrite phases. FE-SEM showed improved grain uniformity and reduced agglomeration in one-pot composites. Electrochemical studies demonstrated enhanced performance for one-pot samples, achieving a specific capacitance of 1067.2 F/g at 10 mV/s for x = 0.5, with 88% capacitance retention after 5000 cycles, indicating excellent long-term electrochemical stability. HEC measurements further showed superior activity for the one-pot x = 0.5 sample, delivering an open-circuit voltage of 1.52 V, short-circuit current of 45 mA, and power output of 68.4 mW. The improved performance is attributed to synergistic interfacial effects, oxygen vacancies, and efficient ionic transport facilitating spontaneous water dissociation and redox reactions. Density functional theory calculations supported the experimental findings by confirming favorable electronic structure and enhanced charge transport. These results highlight the importance of synthesis optimization and compositional tuning for multifunctional ferrite-based energy storage and conversion devices.

Defect-engineered calcium-doped graphitic carbon nitride (Ca-g-C3N4) nanorods were synthesized to modulate interfacial charge transport and electronic structure for visible-light-driven photocatalysis. Density functional theory (DFT) calculations confirmed the semiconducting nature of pristine g-C3N4 and n-type degenerate behavior after Ca incorporation. Substitution of Ca into the tri-s-triazine lattice introduced lattice strain, shifted the Fermi level from -3.334 eV (g-C3N4) to -2.336 eV (Ca-g-C3N4), and generated localized electronic states within the bandgap. Density-of-states (DOS) analysis evidenced enhanced charge carrier separation and suppression of electron-hole recombination kinetics. The optimized composition (CCN0.4) exhibited superior photocatalytic activity, achieving 97 % degradation of Methylene Blue (MB) within 90 min under visible irradiation. The pseudo-first-order rate constant (0.018 min-1) was approximately 2.6-fold higher than that of pristine g-C3N4 (0.007 min- 1). Bandgap narrowing from 2.57 eV to 2.36 eV increased visible-light absorption cross-section, while defect-induced surface charge redistribution enhanced electrostatic interaction and physisorption of MB (97 %). Radical scavenging experiments identified hydroxyl radicals (center dot OH) as the dominant reactive species, consistent with the Ca-induced shifts of conduction band minimum and valence band maximum, which optimize thermodynamic driving force for center dot OH generation. The CCN0.4 photocatalyst demonstrated robust stability, retaining 87 % degradation efficiency over four consecutive cycles with negligible structural degradation. Importantly, in real wastewater containing mixed cationic dyes and pharmaceutical residues (UV absorption at 200-230 nm), Ca-g-C3N4 selectively degraded MB with near-complete removal, while leaving pharmaceutical compounds largely intact. These findings establish Ca doping as an effective strategy to engineer lattice strain, electronic band alignment, and interfacial charge transport in g-C3N4, yielding twofold photocatalytic rate enhancement and selective pollutant removal in complex wastewater environments.

Lanthanide ions doped hydroxyapatite nanoparticles are well-established in biomedical applications. While lanthanide elements are closely grouped in the periodic table and share many similar characteristics, small differences in their effective ionic radii can lead to changes in the physiochemical and biological properties of hydroxyapatite (HA) substitutes. Lanthanum doped hydroxyapatite (HA-La) and samarium doped hydroxyapatite (HA-Sm) nanoparticles of moderate crystallinity (similar to 60-64 %) have been successfully synthesized using the co-precipitation technique. The effects of doping the above-mentioned lanthanide ions on the structural, morphological, drug release and in vitro biocompatibility properties of hydroxyapatite samples were investigated experimentally using powder XRD, FTIR, TEM, BET surface area analyser, XPS, UV-Visible spectroscopy, Alamar blue and Pico green assays. Besides, the prepared samples were also modelled for making the theoretical investigations on the density of states and band structures. XPS analysis confirmed the successful incorporation of La3+ and Sm3+ into the HA lattice without the formation of secondary oxide phases. BET analysis showed almost 35 % increase in surface area for HA-La (from 89.3 m(2)/g to 120.4 m(2)/g) as compared to hydroxyapatite. Drug release studies using ciprofloxacin demonstrated prolonged release behavior, with HA-La releasing 90 % of the drug over 72 h. Furthermore, theoretical investigations reveal that the doping of hydroxyapatite with lanthanum and samarium leads to the narrowing of the band gap from 5.2 to 4.61 eV. In vitro studies with rat mesenchymal stem cells showed enhanced biocompatibility, with HA-La exhibiting of 21 % increase in cell viability and almost 11 % higher DNA content after 7 days compared to control hydroxyapatite. While some previous studies have reported reduced cell viability for lanthanide-doped hydroxyapatite, our findings demonstrate enhanced biocompatibility, with increased cell viability and DNA content. The superior cell viability and proliferation on HA-La suggests its enhanced biocompatibility, making it more suitable for promoting cell growth and tissue regeneration.

Water pollution caused by pollutants like organic dyes and heavy metal ions is accountable for problems related to health, economy, and environmental degradation. Metal oxide nanomaterials such as ZnO have extensive potential to tackle water pollution. In the present study, pure, 3 and 6 at% Fe-doped ZnO nanoparticles were synthesized via high-energy ball mill cum solid-state reaction route. The samples were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller (BET) technique, UV-visible and photoluminescence spectroscopies. The crystallite size decreased, whereas structural defects increased with Fe concentration. The band gap narrowing (3.36-3.23 eV) has been observed with an increase in Fe doping. The light-emission properties of samples were analyzed using CIE plots. Also, DFT+U calculations were performed to predict the impact of Fe-doping on the crystal structure and electronic & band structure of ZnO. Photocatalytic degradation ability of the nanostructures towards methylene blue (MB) dye was improved from 59.8 % to 90.7 % with Fe doping, and degradation follows pseudo-1st order kinetics. With Fe-doping, Ni ions removal capability of ZnO from water enhanced from 14.7 % to 48 %, and DFT studies of Ni-adsorption on the pure and Fe-ZnO surfaces also predicted this trend.

Ever-increasing global energy requirements and environmental pollution have directed major research focus on developing sustainable energy conversion and energy storage technologies.

In the present study, we have synthesized a ZnO/g-C3N4 heterojunction by adjusting the concentration of zinc nitrate hexahydrate and explored the impact of this varying concentration on the material's physical properties via experimental methods and density functional theory (DFT) calculations. The band gap energies were assessed via UV-visible spectra, and band gap values of ZnO/g-C3N4 vary in the range of 2.55-2.70 eV, and the band gap of g-C3N4 (CN) has a value of 2.76 eV. Thus, heterojunctions exhibit a slightly narrower band gap compared to pure CN, and DFT calculations have also supported this observation. DFT study predicts the stability of the ZnO/CN heterojunction, further confirmed by experimental studies. The existence of the elements (Zn, O, C, and N), along with their valence states, was determined by X-ray photoelectron spectroscopy (XPS) analysis. The heterojunctions demonstrate significantly improved dye degradation percentage toward MB dye compared to the individual components. With the optimized concentration of ZnO, the ZnO/CN (ZCN4) heterojunction achieved a maximum dye degradation efficiency of 97%. The superior performance of the ZCN4 heterojunction has been ascribed to the optimized zinc precursor concentration, enhanced charge separation, reduced recombination rate of charge carriers, and narrowest band gap among the synthesized heterojunctions. The charge carrier dynamics were investigated through photoluminescence (PL) and electron paramagnetic resonance (EPR) analyses, revealing reduced recombination of charge carriers. Scavenger experiments identified superoxide anions as the dominant reactive species in the photocatalytic degradation process. The influence of pH on the photocatalytic performance was systematically examined, with point of zero charge (pHPZC) measurements providing valuable insights into the surface charge interactions under varying pH conditions. The recyclability of the ZCN4 heterojunction was also evaluated over multiple cycles, demonstrating its stability and reusability. Furthermore, the Fourier transform infrared spectroscopy (FTIR) analysis of the recycled sample provided insights into the mineralization of the adsorbed dye molecules, confirming the degradation of organic pollutants. These findings underscore the potential of ZnO/CN heterojunctions as efficient photocatalysts for environmental remediation applications.

The present work focuses on the study of effect of Cd-doping on the structural, optical, and photocatalytic degradation efficiency of methylene blue (MB) and methylene orange (MO) dyes on ball-milled cum solid-state reaction synthesized copper oxide (CuO) nanoparticles. X-ray diffraction reveals the presence of a monoclinic CuO phase only, which confirms the successful doping of Cd in the CuO matrix. The XRD and TEM analysis suggests the shrinkage of particle size (47 to 40 nm) of CuO nanoparticles with increase of Cd-doping content. The optical studies also reveal the narrowing of CuO band gap from 3.48 to 3.43 eV with increase of doping percentage. XRD and PL analysis confirms the enrichment of structural defects of CuO lattice with introduction of dopant into it. Further, the DFT + U approach was used for crystal structure, state of density, and band structure evaluation. The sunlight-driven photocatalytic degradation activity of the samples was tested against pollutants (MO and MB dyes). The degradation efficiency of CuO nanoparticles was found to be enhanced with Cd-doping concentration. 3 mol

Environmental concern essentially demands solemn consideration of industrial waste -water containing organic dyes. To develop efficient photocatalysts for degradation of organic dyes in waste water, metal -oxide nanostructures are the promising candidate owing to their tunable physical properties. The present work emphasizes on the experimental and first -principle (DFT + U) studies to understand the impact of magnesium doping on the structural, optical and electrical properties, and photocatalytic degradation tendency of zinc oxide (ZnO) nanoceramics. The ZnO lattice contraction endorsed by Mg -doping, has been examined mutually from the first principle calculations and Rietveld refinement investigations. The decrease in crystallite -size (93 to 88 nm) and enrichment in structural imperfections of Zn1-xMgxO nanostructures were analyzed with Williamson -Hall peak profile methods. The band gap broadening of ZnO with Mg doping was demonstrated by UV-visible spectroscopy (3.32 to 3.43 eV) which was further confirmed from DFT + U (3.39 to 3.55 eV) calculations. The increase in dielectric constant and reduction in ac conductivity has been observed due to Mg addition. The photocatalytic performance of Zn1-xMgxO nanostructures was evaluated under sunlight for Methylene -blue (MB) and Congo -red (CR) dyes. The performance has been optimally improved with 6 mol% Mg content leading to degradation of 86.2 % and 58.3 % of MB and CR dyes respectively in 160 min.

The present manuscript emphasizes the versatility of Mg-doped CuO nanostructures for environmental remediation (photocatalytic degradation of pollutants) and biomedical applications (anticancer activity) thus highlighting their potential impact in addressing societal and health challenges. The primary focus of the manuscript is the synthesis, characterization, and applications of Mg-doped CuO nanostructures. In order to meet this purpose, pure and Mg doped CuO nanostructures were synthesized using the solid-state reaction method and ball milling techniques. To characterize the prepared samples, X-ray diffraction, transmission electron microscopy, UV-Visible, photoluminescence, and Raman spectroscopy techniques were utilized. A profusion of structural defects and the reduction in crystallite size have been observed in CuO nanomaterial’s due to the dopant's complete incorporation into the CuO lattice. Additionally, the band gap of CuO has been observed to decrease as a result of Mg doping. Density functional theory was employed to simulate the effect of Mg on the properties of CuO. The efficiency of photocatalytic degradation aided by sunlight against methylene blue increased from 50.8% to 89.5%. MCF-7, a cell line representing human breast adenocarcinoma, was utilized to assess the cytotoxicity of Mg/CuO samples. CuO nanoparticles enriched with Mg are viable biocompatible anti-cancer agents and prospective photocatalyst for the removal of environmental pollutants from aqueous solutions, according to the findings of this study.

Eco Friendly green synthesis method with the use of green tea leaves is used in preparation of Iron nano particles in this research. This method is rarely ever used. Green synthesis methods are one of the recently developed environmentally favorable methods. Green process methods indeed play a crucial role in the advancement of nanotechnology by offering several benefits such as minimizing environmental impact and ensuring the safety of both researchers and end-users. Green manufacturing of catalysts supports sustainable advanced oxidation processes for degradation of organic products. Polyphenol contents which are already in plants prepare the metal nano particles and are revived by non-harmful biodegradable chemical components. High temperature and energy is not required in green synthesis method. The are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterized the synthesized nanoparticles. UV-vis spectrophotometer was used for calculating degradation efficiency of Nanoparticles (NPs). Degradation of Methylene Blue (MB) dye was investigated under sunlight with respect to time and catalyst concentration. MB dye was used as a model dye.

Transition metal doped Zinc oxide (ZnO) thin films with wide band gap semiconducting nature have diverse range of applications including, gas sensors, optical and optoelectronic devices, electronics and spintronics spintronic devices etc. In the present study, Manganese (Mn)-doped ZnO thin films deposited on glass substrates using RF-magnetron sputtering have been investigated for their optical and electrical behavior aiming at resistive random access memory applications. To study the influence of Mn doping and correlation between the structural and the physical properties of the films, the samples were characterized by X-ray Diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDS), UV-VIS spectrophotometry and X-ray photoelectron spectroscopy (XPS). The films are found to be crystalline and a decrease in lattice parameter from 2.6049 angstrom to 2.5845 angstrom, an increase in optical band gap from 3.27 eV to 3.35 eV and a decrease in Urbach energy from 0.222 eV to 0.171 eV, is observed with increase in Mn-concentration. The electrical performance of the film with highest Mn-content is found to be more suitable for resistive memory applications. Tailoring the electrical behavior of the film by incorporating Mn as dopant is an important approach to find suitable material combination for novel memory devices.

The present work focuses on the detailed investigation of the structural, optical and antibacterial properties of undoped and Ni-doped CuO nanostructures. The CuO nanostructures with different mol% (0, 1 and 3) of nickel oxide have been synthesized using the ball milling for 20 h, followed by calcination for 4 h at 500 °C. The X-ray diffraction patterns reveal that all the samples contain only CuO with a monoclinic phase and indicate the successful doping of Ni into the host matrix. The Rietveld refinement of the XRD patterns indicates the decrease in structural parameters with increase in dopant concentration. The results of the Williamson–Hall method reveal the decrease in crystallite size and increase in micro-strain with Ni-doping. The optical band energy of the CuO nanoparticles has been obtained with the help of UV–visible data, and it is found to increase with the increase in Ni content. The detection of various types of defects and vacancies in CuO nanoparticles has been carried out using photoluminescence spectra. The antibacterial activity of the synthesized CuO nanostructures has been investigated against pathogenic bacteria (S. aureus and E. coli) using the agar well diffusion method.

In this work, V-doped and (Sm, V) co-doped ZnO samples have been synthesized using ball milling method followed by heat treatment. The dependence of structural, optical, electrical and dielectric properties of V:ZnO samples on the Sm doping concentration has been explored. The structural properties have been studied by means of X-ray diffraction (XRD) and Rietveld refinement. Oxidation states of the elements present in the samples are determined using X-ray photoelectron spectroscopy. Raman spectra of the samples further verified the observations obtained from XRD. The crystallite size and microstrain have been estimated from the Williamson-Hall analysis. Microstrain increases from 0.814 x 10(-3) to 1.01 x 10(-3) with increase in the Sm doping level. The morphology of the grains is significantly affected by the Sm doping. The enhancement of defect density with Sm doping is responsible for the observed red shift (3.29-3.19 eV) in the band gap. The frequency dependence of the dielectric properties has been studied at various fixed temperatures ranging from 25 to 350 degrees C. The increase in real dielectric constant with dopant content indicates the enhancement of energy storage capacity. The ac conductivity follows Jonscher's power law and it increases up to 1 mol% Sm concentration. Further increase in Sm extent leads to the decrease in ac conductivity. The impedance spectroscopy has been performed to understand electrical behavior of samples and Cole-Cole plots are fitted against the equivalent circuit model. The electrical activation energy values for conduction and relaxation vary in the range: 0.281-0.269 eV and 0.260-0.243 eV, respectively.

Iron and vanadium co-doped ZnO nano-structures have been synthesized by solid state reaction method and the influence of Fe content on their structural, optical, dielectric and transport properties was investigated. The structural and optical characterizations of samples have been carried out by X-ray diffraction (XRD), trans-mission electron microscopy, Raman, UV-Visible and photoluminescence spectroscopy. Rietveld refinement of XRD data revealed that the lattice parameters and unit cell volume of the wurtzite ZnO decreased with Fe doping. The decrease in crystallite size and increase in micro-strain with doping have been observed from Williamson-Hall and size-strain analysis. The red shift in the band gap (from 3.29 to 3.24 eV) and increase in the dc activation energy (from 0.196 to 0.207 eV) with increase in Fe concentration are attributed to the enhancement of structural disorder/defects. The decrement in dielectric constant from 160 to 25 and ac conductivity from 16.6 x 10(-6) to 1.4 x 10(-6) at 10 kHz have been observed with Fe doping. The modulus and impedance studies revealed the presence of non-Debye relaxation, and contribution of grains and grain boundaries to the polarization. The study also revealed that the addition of Fe significantly modified structural, optical, dielectric and transport properties of the samples.

The sensitive correlation between optical parameters and strain in Mo$S_2$ results in a totally different approach to tune the optical properties. Usually, an external source of strain is employed to monitor the optical and vibrational properties of a material. It is always challenging to have a precise control over the strain and its consequences on material properties. Here, we report the presence of a compressive strain in Mo$S_2$ crystalline powder and nanosheets obtained via the process of ball-milling and probe sonication. The diffraction peaks in the X-ray diffraction pattern shift to higher 2$\theta$ value implying a compressive strain that increases with the processing time. The absorption spectra, photoluminescence and Raman modes are blue-shifted w.r.t the bulk unprocessed sample. The observed blue-shift is attributed to the presence of compressive strain in the samples. Whereas in thin nano-sheets of Mo$S_2$, it is very likely that both quantum confinement as well as strain result in the observed blue-shift. These results indicate that by optimizing the processing conditions and/or time, a strain of desired amount and hence tunable shift in optical properties of material can be achieved.

In the present study composites of ZnO and V2O5 (3, 6 and 9 mol%) were synthesized by solid state reaction method and the influence of V2O5 on the structural, microstructural, optical, dielectric and transport properties of final product have been investigated. The characterization of samples has been carried out by employing various experimental techniques such as XRD, FESEM, RAMAN, UV-Visible spectroscopy and photoluminescence. Information regarding the phase and structural parameters has been extracted using Rietveld refinements and microstructural using Williamson-Hall (W-H) analysis. Samples were also investigated for dc and ac electrical behavior. The present study revealed that the presence of V2O5 in ZnO-V2O5 composite plays a significant role in altering its structural, optical, dielectric and transport properties. An effort has also been made to correlate the structure with optical, dielectric and conduction properties of synthesized composites. (C) 2020 Elsevier B.V. All rights reserved.