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Abstract: Mn substituted ZnO nanoparticles with compositional formula Zn1−x Mn x O where x = 0.00, 0.04 and 0.08 were synthesized by sol-gel route. All the samples sintered at 650 °C for 12 h in a furnace followed by furnace cooling up to room temperature. X-ray diffraction (XRD) studies shows the presence of hexagonal crystal structure as same as parent compound (ZnO) in all samples. The lattice parameters ‘a’ and ‘c’ were determined from XRD data and found that they increase linearly with the Mn content, which suggests that doped Mn ions go to Zn sites. Grain size, X-ray density and Atomic packing fraction (APF) were evaluated using XRD data and found that grain size increases while X-ray density and Atomic packing fraction (APF) decreases with dopant concentration increases. The functional groups and chemical interactions of Mn substituted Zinc oxide samples were also determined at various peaks using FTIR data and observed the presence of function groups in the samples. Results of such an investigation presented in this paper. [Copyright &y& Elsevier]

This work focuses on the synthesis and characterization of nanoscale nickel oxide (NiO) nanoparticles doped with manganese (Mn) utilizing the cost-effective co-precipitation technique. For extensive characterization, a range of analytical methods are used, such as photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, ultraviolet–visible (UV) spectroscopy, and Brunauer–Emmett–Teller (BET) surface area analysis. The findings demonstrate that the addition of Mn causes the synthesized nanoparticles' crystalline size to decrease, which narrows the band gap to 3.13 eV. Furthermore, compared to pure NiO (44.11 m2/g), the surface area of Mn-doped NiO increases to 178.87 m2/g. Also as compared to pure NiO the electron-hole recombination rate of % Mn-doped NiO has decreased and an increase in the defect is observed. The study of Mn-doped NiO nanoparticles' photocatalytic activity against Rhodamine B (Rh. B) demonstrates their improved efficiency under solar light irradiation, as evidenced by their degradation up to 97.57 %, which is higher than that of pure NiO (90.94 %) in 70 min. Numerous aspects are investigated, including pH, catalyst dosage, original dye concentration, and scavenger studies. Studies on regeneration show that 5 % Mn-doped NiO nanoparticles may be recycled effectively and steadily for up to five cycles. These results demonstrate how effective photocatalysts for environmental remediation applications may be made from Mn-doped NiO nanoparticles. [ABSTRACT FROM AUTHOR]

The hydrothermal technique was used to synthesize the GO-based Ti-doped Co 3 O 4 nanosheets and investigate their photocatalytic properties. These synthesized smart and active materials degraded the mixed dyes of Methylene orange (MO) and Methylene blue (MB) under the sunlight within 180 min with an effective efficiency of 94.85 %. Various physical parameters were studied by using distinct characterization techniques related to structural, compositional, optical, and I–V characteristics. The effects of Young's modulus, stiffness, bulk modulus, microstrain, stacking fault, and dislocation density were studied in detail. The conversion of phase was identified by using Raman spectroscopy. The effects of band gap, surface area, and photosensitivity were illustrated thoroughly. The effect of scavengers on the photocatalytic efficiency was observed and it was concluded that both electrons and holes are activated during the photocatalytic activity. The doping of Ti has played a crucial role in enhancing surface area, electron transfer rate, photosensitivity, and reduction in the bandgap. These smart materials are also useful for photodetector applications. [ABSTRACT FROM AUTHOR]

The present research work employed a hydrothermal technique to synthesize GO-based Pure Bi 2 O 3 and GO-based Fe-doped Bi 2 O 3 mesoporous nanocomposites. X-ray diffraction, Raman spectroscopy, FE-SEM, EDAX, UV–Vis, Photoluminescence, and BET were introduced to characterize the nanocomposites that were synthesized. The photocatalytic degradation of Congo red and Methylene Blue-Methyl Orange mixed dye under solar light irradiation was then scrutinized. The results showed that the photocatalytic efficiency of GO-based 0.5 % Fe doped Bi 2 O 3 was significantly greater than all other synthesized samples, with 91.57 % in 90 min for Congo red and 91.47 % in 120 min for MO-MB dyes. The enhancement in the degradation of harmful dyes in GO/0.5 % Fe doped Bi 2 O 3 nanocomposite was attributable to a larger surface area of about 102.571 m2/g, the development of defects, low band gap and the production of higher active sites. According to the regeneration investigation, GO-based 0.5 % Fe doped Bi 2 O 3 nanocomposite can be effectively recycled up to three cycles while keeping high efficiency without a significant reduction in degradation rate and excellent stability. [ABSTRACT FROM AUTHOR]

Mn doped ZnO nanocrystals were synthesized by sol–gel technique and sintered at 400 °C. Sintered samples characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and LCR-Q meter. X-ray diffraction patterns reveal that obtained samples have hexagonal (wurtzite) crystal structure. Volume of unit cell increases with Mn doping, indicating the successful incorporation of Mn ions into ZnO lattice. The morphology changed from hexagonal to spherical–hexagonal structure and size ranging from 30 nm to 43 nm with Mn doping. Average crystallite size of ZnO nanocrystals decreases with Mn doping. The functional groups and chemical interactions of Mn substituted ZnO samples were determined at various peaks using FTIR data and clearly confirmed that the formation of pure and Mn doped ZnO nanocrystals. Dielectric constant and dielectric loss decreases with increasing Mn concentration and frequency. [ABSTRACT FROM AUTHOR]

Abstract: Samples of Eu1−x Pr x Ba2Cu3O7−δ with compositions x=0.0, 0.1 and 0.3 were prepared by the solid state reaction route. The structural, electrical and microstructural properties were investigated by X-ray diffraction, Physical Property Measurement System (PPMS) and scanning electron microscopy (SEM) techniques respectively. The lattice parameters, oxygen deficiency, hole concentration in the CuO2 plane, average charge on Cu–O plane were evaluated from X-ray diffraction data. From XRD data, it is observed that the lattice parameters and oxygen deficiency increase with increasing Pr concentration. It was also observed that the hole concentration in CuO2 plane and average charge on Cu–O plane decrease with increasing Pr concentration. The electrical resistivity of all samples was measured in the temperature range 300K to 4K. It was found that the normalized transition temperature decreases with increasing Pr concentration. This may be due to reduction in hole concentration or average charge on Cu–O plane. From scanning electron microscopy images, it was observed that grain size increases with increasing Pr concentration. This increase may be the possible cause for suppression of T c. [Copyright &y& Elsevier]

Reduced Graphene Oxide (rGO) decorated δ-MnO 2 and Ni-doped δ-MnO 2 samples have been synthesized by a microwave-assisted co-precipitation technique which is low cost, simple and fast reaction method. The structural and morphological properties of synthesized samples have been characterized using x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). XRD result indicates that all samples have monoclinic crystal structure with δ phase of MnO 2. The morphologies of MnO 2 transformed into perforated porous nanoflakes with Ni doping and rGO composition in MnO 2. AFM images confirmed that surface roughness for 3 % Ni-doped MnO 2 samples is higher due to the chemical adsorption of samples. Raman spectroscopy results show the presence of vibrational and Raman active modes of MnO 2.X-ray photoelectronic spectroscopy revealed the presence of mixed valencies of Mn such as Mn2+, Mn3+, and Mn4+ in prepared nanocomposites while Ni shows 2+ valency. The specific capacitance (Cs) of pure δ -MnO 2 samples were 68 Fg-1 and rGO decorated 3 % Ni-doped MnO 2 composition 694 Fg-1 at 10 mVs−1 respectively. EIS data of the rGO decorated Ni-doped MnO 2 composition samples confirm that the porous nanoflake-shaped rGO decorated 3 % Ni-doped MnO 2 composite sample has a low resistance value among all samples. These results reveal that rGO-decorated 3 % Ni-doped MnO 2 nanoflakes should be a promising material for designing and fabricating the electrode material for high-performance supercapacitors. [Display omitted] • The manuscript contains a novel synthesis method of 2D porous nanoflakes of Ni-doped δ-MnO 2 and rGO composition by microwave-assisted co-precipitation technique for supercapacitor application. • Maximum specific capacitance for the GNMO3 sample was achieved at 694 Fg-1 at 10 mVs−1 with higher stability. • The present work examines how Ni and Mn valencies and surface vacancy defects actually contribute to an increase in specific capacitance. • The defects observed due to non-conjugated carbon and the role of Ni are responsible for the enhancement in capacitance which was scrutinized by XPS results. [ABSTRACT FROM AUTHOR]

The effect of Mn doping on the structural physical, morphological and optical properties of Zn 1− x Mn x O nanoparticles prepared by novel co-precipitation route. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis spectroscopy. Broad peaks observed in XRD patterns indicates that all samples were nanocrystalline with hexagonal phase. Studied lattice parameters and volume of unit cell as a function of Mn content. The crystalline size, lattice strain, stress and strain energy density of Mn doped ZnO nanoparticles were determined from XRD patterns using W–H three models. The results obtained yields strain, stress and strain energy density increases with increasing Mn content and crystalline size decrease. Among the developed models, UEDM model was observed to be the best fit for co-precipitation route. The transmission electron microscopy (TEM) result confirms that mean particle size of Zn 1− x Mn x O nanoparticles were about 20–27 nm. The optical study shows the decrease in optical energy band gap with Mn doping and confirm that Mn 2+ ions substituting in ZnO materials. The u parameter and bond length of Mn doped ZnO nanoparticles were also investigated in this paper. [ABSTRACT FROM AUTHOR]