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Disordered pyrochlores Ce2Zr2-xSixO7 (x = 0.0, 0.25, 0.50, and 0.75) with appropriate compositions have been manufactured by normal micro-emulsion method and the effects of Si doping on dielectric and electrical properties were observed. The as-synthesized materials were analyzed via various techniques including X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy, X-ray fluorescence (XRF) spectroscopy, Scanning electron microscopy (SEM), the temperature-dependent electrical capacity, and the frequency-dependent dielectric measurements. The XRD results revealed that the synthesized pyrochlores were single phased except x = 0 with crystallite size ranging from 18 to 30 nm. SEM analysis showed that particles were homogenous and well distributed. The resistivity of material first increased and then decreased showing metal to semiconducting transition. A decrease in dielectric properties with the increase in frequency was observed owing to natural magnetic resonance phenomenon. The dielectric and electrical measurements were enhanced by doping of Si contents which revealed that the prepared material is suitable for frequency filters, oscillators, and resonators. [ABSTRACT FROM AUTHOR]

Photoactive materials provide a greener way to convert solar radiation into chemical energy, fuels and for the photodegradation of organic pollutants. We show here nanostructured LaDySn2O7/SnSe composite that effectively harvests in the visible‐spectrum and performs actively for CO2 reduction and photodegradation of foron blue (FB) dye. Various spectroscopic methods and characterization techniques are employed to explore the structural, morphological, compositional, surface area, optical properties, oxidation states of the elements and valence band position. The optical properties of SnSe revealed their action as photosensitizers for stannate pyrochlore LaDySn2O7 under visible–light irradiation. Admirable photoreduction efficiency for CO2 conversion into methane was achieved for composites relative to individual catalysts. They also show superior photocatalytic degradation > 98.8% for foron blue dye. Whereas, individual photocatalyst LaDySn2O7 is photo‐insensitive in the visible region due to large band gap and the cocatalyst (SnSe) exhibited photodegradation up to 15.5%. No observable deactivation of LaDySn2O7/SnSe was recorded after the five consecutive recycles runs for photodegradation of foron blue dye. [ABSTRACT FROM AUTHOR]

SnS2/ZnTe nanocomposites were successfully synthesized via a two-step methodology incorporating hydrothermal techniques. The resultant nanocomposites underwent comprehensive characterization encompassing morphological, structural, and compositional aspects through the utilization of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Furthermore, the electrochemical performance of these newly synthesized nanostructures was evaluated in the absence and presence of light to ascertain their suitability for energy generation applications. In the context of the hydrogen evolution reaction (HER) against reference electrode 0.185 vs. RHE, it was observed that SnS2/ZnTe electrodes exhibited notably low overpotentials, registering at 185 mV, along with a Tafel slope of 80 mV dec−1 under visible light. These findings underscore the superior catalytic activity of SnS2/ZnTe electrodes in the HER. Moreover, the SnS2/ZnTe electrode demonstrated a substantially reduced overpotential of 105 mV at a current density of 10 mA cm−2, accompanied by a Tafel slope of 47 mV dec−1 under visible light, indicative of a swift and efficient performance in the oxygen evolution reaction (OER). In light of these outcomes, these nanostructures exhibit significant promise as electrode materials for applications in water splitting, thereby contributing to advancements in sustainable energy production. [ABSTRACT FROM AUTHOR]

Graphene oxide based electrode materials show remarkable electrochemical properties due to the improved specific surface area and electrical conductivity for supercapacitor applications. Hydrothermally synthesized graphene oxide based aluminum sulfide nanowalls on nickel foam (NF) have revealed excellent pseudocapacitive behavior with the specific capacitance 2362.15 F g -1 at 2 mVs -1 as observed through cyclic voltammetry. The galvanostatic charge-discharge measurements confirmed a specific capacitance 2373.51 F g -1 at 3 mAcm −2 . Hexagonal phase of the graphene oxide (GO) based Al 2 S 3 nanowalls also showed good discharge time of 820 s and energy density 118.68 WhKg −1 at 3 mAcm −2 . Moreover, the fabricated electrode material exhibited good power density 2663.58 W kg -1 at 20 mAcm −2 . The impedance results also confirmed the pseudocapacitive characteristics and revealed weak contact and Warburg resistances for the electrode material in half cell. Hence, GO based Al 2 S 3 nanowalls performed as a prominent electrode material for asymmetric supercapacitors. Additionally, electrode material also exhibited excellent symmetric behavior, which again suggested a good electrode structure for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Owing to large specific surface area and high electrical conductivity, nanostructured electrodes exhibit improved electrochemical activity for supercapacitor applications. In the present study, structure and morphology of hydrothermally synthesized strontium sulfide and graphene oxide based Strontium sulfide nanorods have been investigated by using XRD and SEM, respectively. Introduction of graphene oxide thin film improves specific surface area and result in the excellent electrical conductivity of Strontium sulfide nanorods. Due to this, graphene oxide based strontium sulfide nanorods illustrate excellent specific capacitance and energy density of 1831.14 F g −1 and 91.56 WhKg −1 , respectively, at the current density of 3 mAcm −2 , as measured by employing three electrode galvanostatic charge discharge system. Moreover, electrode of graphene oxide based strontium sulfide nanorods also shows good electrochemical performance, according to the measurements by symmetric two electrode system. Energy and power density is measured as 10.55 WhKg −1 and 294.35 W kg −1 , respectively. The excellent electrochemical performance of graphene oxide based strontium sulfide nanorods reveals its significance as nanostructured materials for supercapacitor applications. [ABSTRACT FROM AUTHOR]

This article reports the fabrication of Ni-Ti doped derivatives of Sr 2 Co 2 Fe 12-2x O 22 by economical Sol-gel method. At room temperature X-ray diffraction (XRD) pattern of powder was obtained after sintering at 1050 °C. The XRD analysis revealed the formation of pure Sr-Y hexaferrite phase. It was found that the observed values of dielectric parameters decreased with increasing Ni-Ti substitution. The higher values of dielectric constants and dielectric loss factor at lower frequency were owing to surface charge polarization. In all the samples the resonance peaks were also observed. The observed room temperature DC electrical resistivity found to increase from 1.8x10 6 to 4.9x10 9 ohm cm. The observed activation energies values of the fabricated materials are found in 0.52–0.82 eV range. The decrease in dielectric parameters and increase in resistivity of the fabricated samples with substituents suggest these materials have worth application in micro-wave devices as such devices required highly resistive materials. [ABSTRACT FROM AUTHOR]

A simple approach to synthesizing tin selenide nanostructures showing superior photocatalytic performance with variable tin ratios via a facile chemical method is reported in this study. The crystalline phase, morphology, oxidation states of elements, surface composition and optical properties of the photocatalysts were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy, respectively. The photocatalytic activity was evaluated by the degradation of methylene blue (MB) under visible-light irradiation, indicating that SnSe exhibits excellent photocatalytic performance with a maximum % degradation efficiency of MB up to 92.91% after 40 min of light irradiation. These materials were also used as photocatalysts for the degradation of Congo red (CR) and the results showed 98% degradation of Congo red which is much higher than other photocatalysts. The possible degradation pathway is also presented. Indeed, SnSe nanostructures with variable tin ratios behaved as highly efficient photocatalysts and could be promising for future industrial applications for wastewater treatment. [ABSTRACT FROM AUTHOR]

Technologically important ferrites magnetic materials with nominal composition “Sr 2-x Nd x Co 2 Mn y Fe 12-y O 22 ” (x = 0.0 to 0.1 and y = 0.0 to 1.0) were fabricated by the simple sol-gel method. The X-ray diffraction analysis endorsed the formation of well-defined Y-type hexagonal single phase with crystallite size in range of 38–45 nm. Owing to reduction of Fe 3+ ions at octahedral site, an increase in DC resistivity was observed from 4.083 × 10 8 to 2.376 × 10 9 Ω-cm with the increase in substituents content. The two conduction mechanisms operating in ferri- and paramagnetic regions were shown by Arrhenius plot. It was observed that conduction in ferrimagnetic and paramagnetic regions was governed by the hopping of electrons and polarons, respectively. The decrease in Curie temperature “Tc” (553-423 K) was detected as a factor of Nd-Mn content due to decrease in Fe Fe interaction at octahedral site. The changes in the values of dielectric constant (ε ′ ), dielectric loss factor (ε ″ ) and tan loss (δ) follow Maxwell-Wagner model. The relatively high resistivity (2.376 × 10 9 Ω-cm) and low dielectric constants (2.97 at 1 MHz) for the sample with x = 0.1 and y = 1.0 make this material as an excellent candidates for high frequency microwave devices. [ABSTRACT FROM AUTHOR]

Owing to the boom in textile industry in the recent past, there is a stringent requirement to deal with the environmental hazards associated with the azo dyes, a run-off from textile industry, i.e. toxicity to aquatic life and health hazards to humans. The use of nano-sized catalysts for the degradation of these dyes into minerals using sunlight as a primary source of energy is proved as most promising approach to handle the problem. The development of visible light sensitive catalysts is of great concern for the practical realization of dyes degradation. In the present work, we have synthesized LaSmTiZrO 7 via microemulsion technique, while SnSe and their composite by using the hydrothermal approach. The XRD analysis confirmed the formation of LaSmTiZrO 7 , SnSe and their composite. The morphology, specific surface area, oxidation states of elements, surface chemical composition and optical properties of photocatalyst studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) nitrogen adsorption–desorption, X-ray photoelectron spectroscopy (XPS), energy dispersive spectra (EDS) and UV–vis spectroscopy, respectively. The synthesized catalytic materials have then been used for the photocatalytic degradation of mono azo foron blue dye under the visible-light irradiation. The alignment of energy levels shows that the electrons/holes recombination can be minimized with the formation of LaSmTiZrO 7 -SnSe composite. The photodegradation results confirm that the composite has better efficiency under visible light irradiation as compared to that of individual catalysts. The XRD analysis after photodegradation process confirms the structural stability of the composite. [ABSTRACT FROM AUTHOR]

• Sn-Co co-substituted SrSn x Co x Fe 12-2x O 19 strontium hexaferrites were produced by sol–gel method. • Correlation between chemical composition, structural, magnetic and electrical properties was established. • Heterovalent substitution in M-type hexaferrites opens broad perspectives for control of the physical properties. M-type strontium hexaferrites attract great attention due to the scientific importance and practical significance. It was observed the correlation between chemical composition, structural parameters, magnetic and electrical properties in heterovalent double substituted Sr hexaferrites. As substituents were used Co2+ and Sn4+ ions. X-ray diffraction data is used to compute a variety of parameters, including lattice parameters, and size of crystallite, in addition to validating purity of the materials. All investigated samples were single phase and characterized by the P 6 3 / mmc space group. Increase of the substituent concentration leads to the increase of the lattice parameters that correlated well with average ionic radii of the Fe3+, Co2+ and Sn4+. The average size of a crystallite was between 31 and 45 nm. Magnetic parameters were obtained from field dependences of the specific magnetization It was observed non-linear dependence in magnetic properties as function of the chemical composition. Increase of the sn-Co concentration leads to increase of the DC electrical resistivity. The dielectric constant is reduced while DC electrical resistivity increased from 5.94 to 11.7 × 109 Ohm cm, suggesting that materials can be employed in microwave devices because of their high resistivity and minimal dielectric constant. [ABSTRACT FROM AUTHOR]

Tantalum–potassium substituted strontium calcium hexagonal ferrites with chemical composition Sr 0.5 Ca 0.5 Fe 12-2x Ta x K x O 19 (x = 0.0, 0.1, 0.2, 0.3, 0.4) have been synthesized by the sol gel combustion procedure. The structural and morphological characterizations of the synthesized hexaferrites were performed by X-ray diffraction and scanning electron microscopy, respectively. Dielectric and magnetic properties of these samples were also inspected. XRD analysis revealed that all the prepared compounds have pure magnetoplumbite phase and their mean crystallite size was between 34 and 44 nm.The dielectric parameters present resonance type behavior at higher frequency (GHz) region. The dielectric constant increases as the dopant contents increase. The saturation magnetization and remanence show decreasing trend as the concentration of dopants rise in the range of applied magnetic field. The coericivity of all the prepared samples rises with Ta–K concentration and is high enough to be used for longitudinal magnetic recording media. [ABSTRACT FROM AUTHOR]

Currently, the global problem of poisonous and nondegradable organic water pollutants cannot be ignored. Heterogeneous photocatalysis is an advanced oxidation process (AOP) that uses semiconducting materials as a catalyst to clean water. Nanosize semiconductor photocatalysts are well recognized for their practical and cost‐effective way of cleaning up environmental pollution when exposed to visible light. Herein, a simple hydrothermal approach is used to create an MnS/rGO nanocomposite for the degradation of aromatic dyes under visible light. Powder X‐ray diffraction, scanning electron microscopy, and UV–visible spectroscopy are utilized to analyze the synthesized photocatalyst. Methylene blue is investigated for photocatalytic degradation using the MnS/rGO heterostructure nanocomposite. Under visible light, the composite shows photocatalytic degradation efficiency of 91.8% owing to the addition of rGO, its synergistic effects, high specific surface area, and a decrease in photoinduced electron–hole pair recombination. The fabricated nanocomposite MnS/rGO with significantly better photoresponse activity is successfully protected from charge recombination by reduced graphene oxide, which functions as a superb electron‐carrying material. [ABSTRACT FROM AUTHOR]

The effect of Gd-Sn substitution on the structural, electrical and magnetic properties of Sr 1− x Gd x Fe 12− y Sn y O 19 (where x =0.00, 0.025, 0.05, 0.075, 0.1) and ( y =0.00, 0.25, 0.5, 0.75, 1) prepared by the sol–gel combustion method has been investigated. The XRD analysis shows the presence of Fe 2 O 3 phase at higher substitution. The average crystallite size obtained lies between 19–42 nm which is beneficial in obtaining suitable signal-to-noise ratio in high density recording media. The FTIR spectra of annealed samples of SrFe 12 O 19 , Sr 0.95 Gd 0.05 Fe 11.5 Sn 0.5 O 19 show that strontium hexaferrite nanoparticles have been synthesized successfully. DC electrical resistivity shows metal-to-semiconductor transition with temperature. The value of transition temperature increases with dopant content. Room temperature dc resistivity and energy of activation decreases while drift mobility increases on increasing the dopant concentration. The magnetic properties such as saturation magnetization (Ms), remanence (Mr) and coercivity (Hc) decreases with increasing the dopant concentration. [ABSTRACT FROM AUTHOR]

Zirconium copper substituted calcium strontium hexagonal ferrites with composition Ca 0.5 Sr 0.5 Fe 12−2 x Zr x Cu x O 19 ( x = 0.0, 0.2, 0.4, 0.6, 0.8) have been synthesized by the chemical co precipitation procedure. These compounds were characterized by X-ray diffraction, thermogravimetry and scanning electron microscopy. Dielectric and magnetic properties of these hexaferrites were also explored. XRD analysis confirmed the single hexagonal phase of all the compounds and the average crystallite size was between 37 and 47 nm. The dielectric parameters show relaxation behaviour at higher frequencies. The values of dielectric parameters increase with dopants. In the range of magnetic field studied, the saturation magnetization decreases as the dopant contents increase which may be due to the nonmagnetic character of the substituents. The coercivity of the Zr–Cu doped derivatives of strontium calcium hexaferrites is increased up to x = 0.2 and then decreased. The values of coercivity are above 600 Oe which make them suitable materials for use in industries in longitudinal magnetic recording media. [ABSTRACT FROM AUTHOR]

Abstract: Strontium hexaferrite nanoparticles substituted with bismuth and chromium having nominal composition SrFe12−2x Bi x Cr x O19 (x=0.2, 0.4, 0.6, 0.8) have been synthesized by the sol–gel method. The samples are characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), DC electrical resistivity, magnetic and dielectric measurements. The XRD data shows that the nanoparticles are crystallized into single hexagonal magnetoplumbite phase. Room temperature DC electrical resistivity decreases on increasing the Bi–Cr contents. The dielectric constant, dielectric loss and tangent loss decrease with the frequency. The magnetic properties such as saturation magnetization (M s), remanence (M r) and coercivity (H c) increase with increasing the dopant concentration up to x=0.2 and then decrease with further increase in dopant content. Coercivity decreases with increasing the dopant content up to x=0.2 then increases with further increase in dopant content. The increase in M s and M r while decrease in H c indicates that the material with composition SrBi0.2Cr0.2Fe11.6O19 is suitable for magnetic recording media. [Copyright &y& Elsevier]

Highlights: [•] Normal microemulsion method has been used for the synthesis of zirconates nanomaterials. [•] Structure shifted towards highly disordered pyrochlore state with substitution. [•] The electrical resistivity increase with the vanadium content. [•] The dielectric constant show resonance behavior. [•] The synthesized materials are suitable for microwave devices. [ABSTRACT FROM AUTHOR]

Abstract: Nano-spinel nickel ferrites doped with Co–Cr at iron and nickel sites are synthesized by the chemical co-precipitation method and are characterized by the XRD, DC electrical resistivity and hysteresis loops measurements. The XRD analyses confirm the formation of single spinel phase and the crystallite size calculated by Scherer''s formula is found in the range of 17–19nm. This crystallite size is small enough to obtain the suitable signal to noise ratio in the high density recording media. The values of electrical resistivity (8.28×107 to 29.6×107 ohmcm), activation energy (0.545–0.884eV), saturation magnetization (23.67–33.49emug−1) and remanence (12.48–18.67emug−1) are increased up to a doping level of x =0.2 and then starts to decrease. The increase in electrical resistivity, saturation magnetization and remanence suggest that the material with composition Co0.2Ni0.8Fe1.8O4 can be used for applications in microwave devices and high density recording media. [Copyright &y& Elsevier]

Abstract: A sol–gel combustion method has been successfully employed for the synthesis of Sr-hexaferrite nanomaterials doped with Er3+ and Ni2+ at strontium and iron sites, respectively. The X-ray diffraction analysis confirmed the single magnetoplumbite phase and the crystallite size was found to be in the range of 14–16nm, suitable for obtaining signal-to-noise ratio in the high density recording media. The magnetic properties such as saturation magnetization (M s), remanence (M r) and coercivity (H c) were calculated from hysteresis loops. M s, M r and H c are observed to increase with the Er–Ni content. The dielectric constant (ε´) and dielectric loss (tan δ) is found to decrease with the increase in frequency and is explained on the basis of Maxwell–Wagner and Koops theory. The decrease in dielectric constant and dielectric loss but increase in saturation magnetization and remanence with Er–Ni content suggests that the materials are suitable for applications in microwave devices and high density recording media . [Copyright &y& Elsevier]

Abstract: Nanosized strontium hexaferrite doped with a binary mixture of Al–Cr at the iron site is synthesized by the chemical co-precipitation method. The hexagonal phase and the nominal composition of the synthesized nanomaterials are confirmed by X-ray diffraction and energy dispersive X-ray fluorescence analyses. The crystallite size is found in the range of 14–30nm, which is small enough to obtain a suitable signal-to-noise ratio in high density recording media. The average grain size of the material is found in the range of 40–85nm as determined by scanning electron microscopy. The magnetic properties, such as saturation magnetization, remanence and coercivity, are calculated from hysteresis loop measurement, and the value of the magnetic moment is also calculated from the saturation magnetization data. All the magnetic properties are found to decrease with the increase in Al–Cr content, which is due to the occupation of the doped cations at the octahedral sites (12k and 2a) having spin of electrons in upward direction. The variation in the dielectric constant and dielectric loss factor with frequency is discussed on the basis of Wagner and Koop’s theory. It is found that the dielectric constant decreases with the increase in Al–Cr content, which suggests that the doped nanomaterials are suitable for applications in microwave devices. [ABSTRACT FROM AUTHOR]

Abstract: A series of M-type strontium hexaferrite samples having nominal composition SrZr x Mn x Fe12−2x O19 (where x =0.0–0.8) has been synthesized by the co-precipitation method. All the samples synthesized were of single magnetoplumbite phase. The particle size was found to be in the 40–65nm range for the samples annealed at 1193K while the samples annealed at 1443K were in the 100–200nm range. The saturation magnetization increase with temperature and reached maxima for the samples annealed at 1393K and then start to decrease while the coercivity decreases regularly with temperature. The decrease in coercivity is due to the increase in the particle size of the sample with temperature. The saturation magnetization increase for the samples doped with Zr–Mn up to x =0.4 doping rate and higher substitution lead to decrease in saturation magnetization. The coercivity decrease with the increase in Zr–Mn substitution. The behavior of saturation magnetization has been explained on the basis of occupation of the substituted cations at different iron sites. The increase in saturation magnetization and decrease in coercivity suggest that the synthesized materials can be used for the application of recording media. [Copyright &y& Elsevier]

Abstract: Nanocrystalline spinel ferrites with nominal composition Co0.5Mn0.5Fe2−2x Sn x Ni x O4 (x =0.0, 0.2, 0.4 and 0.6) are prepared by the co-precipitation method. The samples are characterized by X-ray diffraction (XRD), energy dispersive X-ray fluorescence (ED-XRF), dc electrical resistivity and hysteresis loops measurements. The powder XRD patterns confirm the single spinel phase and the crystallite size is found in the range of 17–18nm. The lattice constant (a), X-ray density (ρ X-ray) and porosity (P) are also calculated from XRD data. The elemental composition of the synthesized samples is determined by ED-XRF analysis. The dc electrical resistivity (ρ) of all samples is measured in the temperature range of 303–723K and is found to decrease with temperature, indicating the semiconducting nature of the synthesized materials. The room temperature electrical resistivity increases from 10.22 to 40.01×107 Ωcm with dopant concentration while the drift mobility (μ d) decreases from 21.3 to 1.42×10−12 cm2 V−1 S−1. The saturation magnetization (M s) increases from 18.33 to 38.39emug−1 up to x =0.2 and then decreases, while the coercivity (H c) decreases continuously with dopant concentration. The increase in the dc electrical resistivity and saturation magnetization make the synthesized materials suitable for their applications in microwave devices and high density recording media, respectively. [Copyright &y& Elsevier]

Abstract: Strontium hexaferrite nanoparticles with nominal composition SrZr x Cd x Fe12−2x O19 (for x =0.0–0.6) with step increment of 0.2 have been synthesized by the chemical co-precipitation technique. XRD, hysteresis loops measurements and LCR meter were employed to evaluate the structure, magnetic and dielectric properties of SrZr x Cd x Fe12−2x O19 nanomaterials. The XRD analysis confirms the single phase and various parameters such as lattice constants (a and c), cell volume and crystallite size have also been calculated from the XRD data. The crystallite size is found in the range of 28–39nm. The magnetic properties such as saturation magnetization, remanence and coercivity are calculated from the hysteresis loops. Values of saturation magnetization are found to increase up to the substitution level of x =0.0–0.2 while that of remanence and coercivity decrease continuously with increase in Zr–Cd concentration. The dielectric properties as a function of frequency under normal conditions were also measured in the frequency range of 500Hz to 1MHz. The dielectric constants and tangent of dielectric loss factor remained within the range of 3347–30 and 11–0.24, respectively. The decrease in coercivity while increase in saturation magnetization confirms that the synthesized materials are suitable for applications in high-density recording media. [Copyright &y& Elsevier]

Abstract: Nanosized cobalt–manganese ferrites with nominal compositions, Co0.5Mn0.5Fe2−2x Zr x Ni x O4 (x =0.0, 0.2, 0.4, 0.6, 0.8) have been synthesized by the co-precipitation method. The samples are characterized by X-ray diffraction (XRD), dc electrical resistivity and magnetic hysteresis loops measurements. The XRD data showed that all the samples are of single phase and the crystallite size is found to be in the range of 16–18nm. The lattice constant (a), X-ray density (ρ x ), porosity (P) and bulk density (ρ m ) are also calculated from XRD data. The dc electrical resistivity of all the samples is measured in temperature range of 303–723K and is found to decrease with temperature indicating the semiconductor nature of the synthesized materials. The room temperature electrical resistivity of the samples is found to increase from 0.22×107 to 14.5×107 Ωcm and the activation energy from 0.34 to 0.40eV, respectively, the drift mobility, however decreases from 21.3×10−11 to 1.41×10−11 cm2 V−1 S−1 with dopant concentration. This variation in electrical resistivity, drift mobility and activation energy is explained on the basis of the site occupation of the dopants. The saturation magnetization (M s) increases from 18.33 to 50.63emu/g up to x =0.4 and then decreases, while the coercivity (H c) decreases. The increase in the dc electrical resistivity and saturation magnetization suggest that the synthesized materials are suitable for their applications in high density recording media and microwave devices. [Copyright &y& Elsevier]

Abstract: Nanoparticles of strontium hexaferrite doped with Zr–Zn are synthesized by a chemical co-precipitation method. The crystallite sizes of 30–47nm are small enough to obtain a suitable signal to noise ratio for application in the magnetic recording media. The temperature dependent DC resistivity of Zr–Zn doped samples shows metal-to-semiconductor transition in the temperature (T MS) range of 388–408K. The Curie temperature, DC resistivity and activation energy for hopping decrease but the dielectric constant, dielectric loss and drift mobility increase by enhancing Zr–Zn content. With the substitution of Zr–Zn content of x ≤0.4 the saturation magnetization, magnetic moment and remanence increase from 71 to 92kAm−1, 11.2–13.6μB and 55–59kAm−1, respectively, while coercivity decreases from 137 to 34kAm−1. With the improvement in the values of the above-mentioned parameters, the synthesized materials may be suitable for potential application in recording media. [Copyright &y& Elsevier]

Abstract: A series of Al–Ga substituted strontium hexaferrite materials of nominal composition SrAl x Ga x Fe12–2 x O19 (x=0.0–0.8) have been synthesized by the co-precipitation method. The XRD analysis confirms the single magnetoplumbite phase and various parameters such as lattice constants (c and a), cell volume (V), crystallite size (D) and X-ray density (ρ x-ray) have also been calculated from the XRD data. The crystallite size is found in the range of 30–62nm. The elemental composition is determined by EDX analysis. DC electrical resistivity is measured within the temperature range of 300–675K. It is observed that the resistivity increases with the Al–Ga content. The activation energy (E a) and drift mobility (μ d) are also calculated from the resistivity data. The dielectric constant () and dielectric loss (tan δ) have been measured in the frequency range of 80Hz–1MHz. The magnetic properties such as saturation magnetization (M s), remanence (M r) and coercivity (H c) are calculated from the hysteresis loops. Values of , tanδ, M s, M r and H c are found to decrease with increase in Al–Ga concentration. [Copyright &y& Elsevier]

Abstract: The magnetic and electrical behavior of SrZr x Cu x Fe12−2x O19 (where x =0.0–0.8) hexaferrite nanoparticles are reported in this paper. Five samples were synthesized by the chemical co-precipitation method. SrFe12O19 is a semiconductor however doping Zr x Cu x at iron sites resulted in a semiconductor-metal transition at a temperature T M–S. The structural parameters of the samples were obtained by FTIR, XRD, EDX, SEM and TEM analyses. The FTIR spectrum and XRD pattern of the samples showed that the synthesized materials were of a single phase. The particle size was in the range 26–37nm as estimated by Scherrer formula, which is comparable with the values estimated from SEM (40–80nm) and TEM (30–60nm) analyses. AC magnetic susceptibility and DC electrical resistivity measurements were carried out in a temperature range 300–800K. The Curie temperature (T C) decreases on substitution of Zr–Cu. A significant increase in the room temperature resistivity is noted with the addition of Zr–Cu up to x ≤0.4. The drift mobility (μ d) and the activation energy (ΔE) are also calculated from electrical resistivity data. The variation of the dielectric constant (ɛ′) and the dielectric loss factor (tan δ) with frequency in the range 80Hz–1MHz and composition of the sample is observed. [Copyright &y& Elsevier]

A series of Zr–Ni-substituted strontium hexaferrite materials, SrZr x Ni x Fe12−2x O19 (x =0.0–0.8), was synthesized by the co-precipitation method and the crystallite size determined to be in the range of 30–47nm. The saturation magnetization increased from 72 to 98kAm−1 while coercivity decreased from 1710 to 428Oe with Zr–Ni substitution. This improvement in both these properties makes these materials suitable for applications in recording media. The increase in resistivity suggests that the synthesized materials can be useful for application in microwave devices. [Copyright &y& Elsevier]

Strontium hexaferrite SrZr x Mn x Fe12−2x O19 (x =0.0–0.8) nanoparticles were synthesized by chemical co-precipitation and sol–gel combustion methods. The co-precipitation is found to be more suitable because samples synthesized by this method have a single phase for x =0.0–0.8 and DC resistivity is also improved by this method, whereas samples synthesized by the sol–gel combustion method have single phase only when x =0.0–0.4. The dielectric constant and dielectric loss factor are in excellent agreement with DC electrical resistivity data. [Copyright &y& Elsevier]

Coprecipitation method was used to prepare non-stoichiometric pristine copper and iron layered double hydroxide (LDH) doped with zirconium and embedded with reduced graphene oxide. The composite materials (ZrRGOCuFe LDHs) were studied for the photodegradation of methylene blue (MB) dye as a model contaminant from an aqueous solution. These composites were fully characterized by X-rays diffraction (XRD), Scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), Photoluminescence (PL), Raman spectroscopy and Electrochemical Impedance Spectroscopy (EIS). The results of Raman, Photoluminescence and Electrochemical Impedance Spectroscopy revealed the presence of oxygen defects level in the composites. Such defects are believed to be essential for boosting the catalytic potential of the composites. The secondary pollution manifested by transition metal ions is usually tackled by inducing heterogeneous catalysis. Herein, pristine CuFe LDH has been doped with Zr and RGO moieties to realize heterogeneous catalysis within ZrRGOCuFe LDH dopants. An admirable band ranging between 1.74 and 2.0 eV was obtained for the doped materials. The remarkable photodegradation efficiency of 95.2% was achieved by using heterogeneous photocatlyst Zr 0.6 RGOCuFe LDH within 75 min at a pH of 7 , photocatalyst dosage of 1.0 g/L and methylene blue dye solution of 10 ppm under visible light irradiation. The total organic content (TOC) analysis has revealed removal of 92% organic content. Moreover, the catalyst has the potentia to maitain sufficient stability and reusability capacity even after three successive cycles. The reaction kinetics and proposed photocatalytic mechanism were also explained in detail. [ABSTRACT FROM AUTHOR]

Currently, the advancement in energy storage technology is a worldwide-based vital challenge, so researchers focused on the development and design of promising electrode materials for energy storage equipment. Perovskite oxide and transition metal selenide nanocomposites can achieve better cycle stability, efficient electric conductivity, high capacity, excellent redox reaction, and inattentive flexibility as electrode materials for energy storage devices and supercapacitor applications. Herein, we present the designed, fabricated, and electrochemical properties of MnSe-supported SrZrO 3 nanocomposite via the Pechini method that exhibited more efficient capacitive performance than pristine SrZrO 3 and MnSe. The result of electrochemical testing indicates that the SrZrO 3 –MnSe nanocomposite electrode possessed a battery-type pseudocapacitive nature and displayed a boosted specific capacitance of 1204 Fg-1 at a 5 mV/s scan rate in aqueous 1 M KOH solution under a three-electrode setup and maintained 95.2% retention after 3000th cycles. It also showed a higher electrochemical active surface area (1680.5 cm2), higher energy density (40 Wh/Kg), long-term cyclic stability performance, and enhanced rate capability compared to other prepared products. As a result, these findings have shown that SrZrO 3 –MnSe nanocomposite can be considered as potential electrode materials and might have emerging applications in commercial products for energy storage devices and supercapacitors. [ABSTRACT FROM AUTHOR]

Recently, cesium lead halide perovskites such as CsPb 2 Br 5 and CsPbBr 3 have drawn the attention of researchers because of their unique optical, electronic, and chemical properties. To improve the photo and/or chemical performance of such CsPb 2 Br 5 (termed as CPB hereafter), we have realized multiple facile routes for its combination with UV-active TiO 2 nanoparticles. Resultantly developed binary nanocomposites of TiO 2 , CPB perovskites and TiO 2 /CPB-nanocomposite (TiO 2 /CPB-NC) offered a meaningful photochemical contrast between pseudo-successive ionic layer adsorption and reaction (p -SILAR) and electrostatic self-assembly methods for targeting photocatalytic degradation of toxic dyes under solar irradiation and resulted significant performance as reactant for oxygen evolution (OER) as revealed by extensive electrochemical impedance spectroscopy (EIS). In parallel to extensive material-based characterization using SEM, XRD, and UV Vis. etc, the study was further extended to the theoretical investigation of the structure of CsPb 2 Br 5 , and antibacterial activity against gram-positive and gram-negative bacteria namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). RhB degradation of TiO 2 increased from 13% to 58% by deposition of CPB, in parallel to 100% inhition zone growth. [Display omitted] [ABSTRACT FROM AUTHOR]

Electrocatalytic water splitting is an essential hydrogen production method for resolving present energy shortage and progress toward more efficient technologies. For this purpose, a versatile and cheap electrocatalysts are the main challenge along the way. In this report, we synthesized vanadium telluride and carbon nanotube (VTe–CNT)‐based nanocomposite via facile hydrothermal route. The VTe–CNTs are characterized by X‐ray diffraction analysis, scanning electron microscopy, energy‐dispersive spectroscopy, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller. These characterizations depict nanosphere structures, morphology, and high surface area that maintains high porosity, which are essential for inclusive water‐splitting phenomena in 1.0 M solution of KOH. Additionally, the electrochemical performance of VTe–CNTs has shown best O2 evolution reactions activity with of onset potential of 1.42 V versus reversible hydrogen electrode and required 10 mA/cm2 of current density at 278 mV overpotential, which is excellent among other electrocatalysts, VTe (342 mV@10 mA/cm−2) and CNTs (365 mV@10mA/cm−2). Moreover, VTe–CNT exhibits remarkable stability for almost 20 h. It also requires a low onset potential of 0.05 V with a small Tafel slope of 47 mV/dec for H2 evolution reactions. Hence, this research might facilitate the easy transportation of electrons and open up the new era, serving as an excellent replacement for noble metal–derived materials. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) stands out as a highly promising conducting polymer with potential for advanced utilization in high-performance pseudocapacitors. Therefore, there exists a pressing need to bolster the structural durability of PANI, achievable by developing composite materials that can enhance its viability for supercapacitor applications. In this particular study, a pioneering approach was undertaken to produce a novel NiMn2O4/PANI supercapacitor electrode material. A comprehensive array of analytical techniques was employed to ascertain the structural configuration, morphology, oxidation states of elements, composition, and surface characteristics of the electrode material. The electrochemical evaluation of the NiMn2O4/PANI composite shows a specific capacitance (Cs) of 1530 ± 2 F g−1 at 1 A g−1. Significantly, the composite material displays an outstanding 93.61% retention of its capacity after an extensive 10 000 cycles, signifying remarkable cycling stability, while the 2-electrode configuration reveals a Cs value of 764 F g−1 at 5 mV s−1 and 826 F g−1 at 1 A g−1 with a smaller charge transfer resistance (Rct) value of 0.67 Ω. Chronoamperometric tests showed excellent stability of the fabricated material up to 50 h. This significant advancement bears immense promise for its potential implementation in high-efficiency energy storage systems and heralds a new phase in the development of supercapacitor technology with improved stability and performance metrics. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) is a crucial energy-storing and energy-changing half-process in water splitting. It is critical to expand the availability of renewable energy reservoirs, and effective electrodes must be robust and possess a high level of catalytic activity. However, it is difficult to eliminate overpotential and improve the performance of OER. In this study, Erbium (Er)-doped samarium oxide (Sm 2 O 3) was synthesized by a facile co-precipitation technique. Using X-ray diffraction analysis, it was determined that a Sm 2 O 3 cubic structure was formed when sharp peaks were observed. Using Fourier-transform infrared (FTIR spectroscopy) and scanning electron spectroscopy (SEM) pictures, the existence of Sm 2 O 3 crystals was detected and surface geometry was observed. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) confirm the successful Er doping in Sm 2 O 3. The OER activities of pure Sm 2 O 3 and Sm 2 O 3 coupled with Er were determined using electrochemical. In comparison to pure Sm 2 O 3 , a high amount of Er-doped Sm 2 O 3 possessed a low overpotential (365 mV for the OER) and a small Tafel slope (47 mV/dec). Consequently, OER became extremely active, metal oxide's structure and catalytic capabilities were altered by inclusion of rare earth metals. Erbium is an essential component when doped in Sm 2 O 3 that improves the performance of OER. Among all 2% Er doped Sm 2 O 3 is an excellent material for energy conversion. [ABSTRACT FROM AUTHOR]

Clean environment is the basic need for all the living things. Due to increase in population and industrialization, the environmental pollution has been increasing because most of the industries causing pollution attributed to discarding their waste in the environment i.e., in water. By this act of these industries the aquatic as well the human life possesses serious threat. It is necessary to remove these life-threatening chemicals from the environment. In the present study, we fabricated CoNi 2 O 4 , ZnSe and their composite (CoNi 2 O 4 /ZnSe) via facile hydrothermal route and are characterized by various spectroscopy and microscopy analysis to confirm the structure, morphology, surface area along with optical properties of fabricated substance. These materials are then applied for removal of methylene blue under the exposure of visible light. Our finding shows that the CoNi 2 O 4 /ZnSe show better efficiency and it can also be applied for other energy related applications. [ABSTRACT FROM AUTHOR]

Securing an affordable and environmentally friendly fuel source is a pressing global need. Hydrogen gas, renowned for being carbon-free and derived from water, stands as an abundant and low-cost energy resource. Efficient water electrolysis hinges upon selecting economical yet effective electrocatalysts. In this context, copper-based chalcogenides have garnered attention for driving water electrolysis. This report presents a newly developed electrocatalyst: copper sulfide (CuS) supported silver indium selenide-nickel foam (AgInSe 2 –NF) composites, characterized by a diverse array of morphologies. The optimized CuS@15%AgInS 2 electrocatalyst showcased superior performance when related to electrocatalysts based on noble metals and metal sulfides which were reported previously. CuS@15%AgInSe 2 –NF nanocomposite exhibits significant potential in water oxidation, revealing a marked reduction in overpotential: 289 mV at a benchmark current density of 10 mA cm−2 for OER and 85 mV for HER. This heightened efficiency is accredited to various exceptional elements associated with design of nanocomposite, which offers abundant reactive sites and ion transfer pathways within its structure. Furthermore, this design fortifies structural integrity and conductivity of CuS@15%AgInSe 2 heterostructure. Additionally, synergistic interplay between AgInSe 2 and CuS enhances electron transport and augments electrocatalytic properties. Notably, electrocatalyst exhibits exceptional stability, consistently producing hydrogen gas for over 25 h. These findings not only highlight potential of CuS@15%AgInSe 2 for a multitude of OER and HER applications but also underscore effectiveness of material hybridization as a straightforward yet potent method to enhance the electrochemical performance of an electrode. [Display omitted] [ABSTRACT FROM AUTHOR]

Electrochemical water splitting stands as a promising method for harnessing energy from renewable sources. However, substantial overpotential required for sluggish oxygen evolution reaction (OER) hampers its widespread adoption. In this study, a CuSe@PPy hybrid is being created by hydrothermally layering polypyrrole on top of CuSe. This hybrid electrocatalyst outperforms both pure CuSe and PPy in terms of OER efficiency. Structural and morphological analyses, including powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller (BET), confirm that the synthesized CuSe@PPy composite exhibits high crystallinity, nanostructured granular morphology, and a hexagonal structure with a large surface area. Evaluation of its electrocatalytic performance for water oxidation in a 1 M KOH alkaline medium reveals CuSe@PPy hybrid's exceptional durability, achieving 35 mA cm−2 for 100 h. This durability is attributed to PPy coating on its surface, which facilitates efficient electron conduction. Coupling of PPy with CuSe leads to reduced overpotential (248 mV), a lower Tafel slope (30 mV/dec), and decreased charge transfer resistance (2.16 Ω), enhancing OER efficiency. By modifying surface of CuSe with a conducting polymer like PPy, this study underscores potential for improving performance in various applications, including photoelectron-catalytic research and stabilizing material activity. [ABSTRACT FROM AUTHOR]

Future commercial energy conversion and storage requisitions may involve using two-dimensional (2D) materials that retain their structure and are feasible for water electrolysis. In this study, we advance in tuning the electronic arrangement of 2D materials like ZrTe 2 /graphene oxide for electrocatalytic energy conversions such as oxygen evolution reaction (OER) as well as hydrogen evolution reaction (HER). The fabricated materials characterize via X-rays diffraction analysis (XRD), Scanning electron microscopy (SEM), and Brunauer Emmett Teller (BET) adsorption-desorption isotherm to confirm their structure, shape, size and porosity. Subsequently, the fabricated nanocomposite employs for the electrochemical characterization, and the resultant composite shows a meager overpotential of 208 mV with a minimal Tafel slope of 31 mV/dec at a current density of the 10 mA/cm2 for the oxygen evolution process and represents the overpotential of 242 mV@-10 mA/cm2 for hydrogen evolution process. The fabricated ZrTe 2 /GO nanocomposite also shows the high stability of 40 h compared to the individual materials. This strategy provides a novel approach to designing tellurium-based nanomaterials for various applications. [Display omitted] • The ZrTe 2 /GO nanocomposite was fabricated facile hydrothermal strategy. • The generated material displayed a lower overpotential of 208 mV@10 mA/cm2. • The material also showed minimal Tafel value of 31 mV/dec for OER. • The material acquired an overpotential of 242 mV@ 10 mA/cm2 for HER. • The ZrTe 2 /GO nanocomposite exhibits exceptional stability for 40 h in case of OER. [ABSTRACT FROM AUTHOR]

For practical H2 generation, it is currently difficult to create modules for electrochemical water splitting that are efficient and inexpensive over a broad pH range. In this study, a novel ZnC8@NCNT electrocatalyst is fabricated via simple pyrolysis of melamine with zinc chloride and carbon nanotubes (CNTs). The self‐assembled hybrid material was examined to catalyze the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in an alkaline pH range, and the ZnC8@NCNT responds with a lower OER overpotential of 245 mV, and smaller Tafel slope of 50.0 mV dec−1 with the turnover frequency (TOF) of 0.67 s−1 due to its unique structure. The HER response of the generated material is quite satisfactory with an overpotential of 223 mV and a Tafel value of 107 mV dec−1. The fabricated material supported by conductive CNTs increases the catalytic reactivity due to the synergistic manner, which is superior in performance as a cutting‐edge catalyst for water electrolysis in an electrolytic cell. Furthermore, ZnC8@NCNT establishes as a cost‐effective alternative to expensive Ir, Pt, Pd, and Ru‐based catalysts. [ABSTRACT FROM AUTHOR]

Electro-catalytic water splitting for the generation of sustainable energy, is one of the most promising way to convert renewable energy resources into fuel. Water splitting is an impressive and effective process due to its complete lack of CO 2 emissions and its efficiency as an energy storage system. The growth of stable, low cost and active electro-catalyst has imperative role for achieving the electro-catalytic hydrogen generation from water splitting process. Herein, a very simple synthesis strategy of sol gel method was used to reduce the production cost of electro-catalysts. Particular characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and cyclic voltammetry (CV) were accomplished. Transition metals and their oxides were found highly stable, active and shows long term durability for water oxidation process, while manganese (Mn) doped samarium oxide (Sm 2 O 3) electro-catalyst showed promising catalytic performance and found exceptionally very active towards overall water splitting process. Thus, the as-prepared catalysts can be employed for hydrogen generation from water splitting, which is one of imperative sources of renewable energy production. • Electro-catalytic water splitting for the generation of sustainable energy. • Conversion of renewable energy resources into fuel in the form of hydrogen. • Cost-effective electro-catalyst was prepared for water splitting process. • Sol gel method was used to reduce the production cost of electro-catalysts. • Mn-doped samarium oxide electro-catalyst showed high catalytic performance. [ABSTRACT FROM AUTHOR]

This work introduces a rapid, cost-effective, and energy-efficient synthesis method for a copper-based metal-organic framework (CuTz-1) catalyst to overcome challenges in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. Among the electrodes, the CuTz-1/nickel foam (NF) demonstrates superior performance with low overpotentials (142 mV and 82 mV at 10 mA cm−2 and 20 mA cm−2), small Tafel slopes (37.1 mV dec−1 and 51.1 mV dec−1) and high turnover frequency (TOF) value (76 × 10−3 s−1 and 0.277 s−1) for OER and HER, respectively. Remarkably, CuTz-1/NF maintains stable electrocatalytic activity over 20 h. The presented gram-scale synthesis approach offers practical applications in water splitting, particularly where manufacturing processes are a concern. • Nanorods of copper MOF can be prepared on a gram-scale. • Nickel foam was found to be the best substrate to immobilize copper MOF. • The copper MOF catalyst exhibits low overpotential, Tafel slope, and high stability for OER and HER in alkaline media. • The copper MOF/nickel foam is a promising candidate to replace the noble metal-based electrocatalysts for water splitting. [ABSTRACT FROM AUTHOR]

The development of a highly efficient catalyst for water splitting and photodegradation of organic dyes has become the focus of a considerable number of research groups. In the work described here CdZnS@MIL-53(Fe) and ZnS@MIL-53(Fe) were synthesized by the solvothermal method and subjected to thermal degradation at 520 °C in an oxidative environment to obtain CdZnS/Fe 2 O 3 and ZnS/Fe 2 O 3 , respectively. Electrocatalytic activity for the oxygen evolution reaction is analyzed via cyclic voltammetry and linear sweep voltammetry. It was found that CdZnS@MIL-53(Fe) shows maximum catalytic activity for the oxygen evolution reaction and delivers 10 mAcm−2 current density at 95 mV overpotential as compared to MIL-53(Fe)/NF (210 mV) and ZnS@MIL-53(Fe)/NF (112 mV). Similarly, the derivative of it, CdZnS/Fe 2 O 3 , shows maximum catalytic activity for the oxygen evolution reaction and delivers 10 mAcm−2 current density at 90 mV overpotential as compared to Fe 2 O 3 (204 mV) and ZnS/Fe 2 O 3 (115 mV). Based on these results, it is evident that these materials are highly efficient for OER activity compared with other materials in literature. Similarly, CdZnS/Fe 2 O 3 shows maximum photocatalytic activity for the photodegradation of Rhodamine B, up to 75% compared to CdZnS@MIL-53(Fe), which degrades up to 51% of the dye. The synthesized materials were characterized by powdered X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Based on these results the aim is to develop more MOF-based materials and their derivatives by simple heat treatment and to implement them in different catalytic applications. [Display omitted] • Designing of highly efficient catalysts by in-situ incorporation of CdZnS nanoparticles in (MIL-53(Fe). • The newly designed CdZnS@MIL-53(Fe) and its derivative CdZnS/Fe 2 O 3 showed efficient OER activity. • The CdZnS/Fe 2 O 3 is also effective forphotodegradation of Rhodamine B (up to 75% in just 80 min). • The better catalytic activity is due to formation of heterojunction between CdZnS and MIL-53(Fe) or its derivative. [ABSTRACT FROM AUTHOR]

Nowadays, waste discharge and contaminants in drinking water have emerged as a significant global problem. Therefore, it is necessary to remove these pollutants from the water and photo-catalysis is the best technique for this purpose. The co-precipitation technique was employed to produce NiMn2O4 and ZnMn2O4 and a photocatalyst containing NiMn2O4/ZnMn2O4 heterostructure nanocomposite. Various analytical techniques have been ascribed to examine the physical, morphological and optical features of the fabricated catalysts. XRD diffraction peak patterns were utilized to confirm the presence of cubic NiMn2O4, tetragonal ZnMn2O4 and NiMn2O4/ZnMn2O4 phases in a nanocomposite. In photodegradation tests, the nanocomposite catalyst outperformed the individual catalysts. After 60 minutes of visible light exposure, this nanocomposite catalyst eliminated the methylene blue (MB) dye, attaining substantially higher degradation rates than pure NiMn2O4 (66%) and ZnMn2O4 (77%). The nanocomposite catalyst was highly effective against methylene blue (MB) dye with a degradation efficiency of 92%. [ABSTRACT FROM AUTHOR]

The advancement of potent, highly efficient and reasonably priced catalysts is necessary for the production of hydrogen from a renewable source and removal of organic contaminants from waste water. In this study, we demonstrated the dynamic proportion capability of the hydrothermally condensed polymorphic electrocatalyst MgCo 2 O 4 /PANI nanocomposite. The composite material has higher surface area of 264 m2 g-1 and electrochemical active surface area of 299.5 cm2. The MgCo 2 O 4 /PANI nanocomposite exhibits 201 mV of lower overpotential to attain at 10 mA cm-2 of current density and 66 mV dec-1 of reduced Tafel value. The long-term viability for 50 h is demonstrated using MgCo 2 O 4 /PANI at 10 mA cm-2 for O 2 production. The findings of this study demonstrated that MgCo 2 O 4 /PANI nanocomposite is an affordable, non-precious material, which can be utilized to generate H 2 on a large scale. On the other hand, the resultant material was then applied for the Congo Red (CR) dye photodegradation irradiated with visible light with degradation efficiency of 98%. The comparison of nanostructured MgCo 2 O 4 /PANI demonstrates that the electrochemical performance for water oxidation processes as well as degradation process is significantly higher than the pure form. The exceptional catalytic performance of MgCo 2 O 4 /PANI nanocomposite is due to the large quantity of active sites, some immense oxygen vacancies, and a fast electron transfer rate, with a steady oxygen generating stability of 1500 cycles confirm the endurance of MgCo 2 O 4 /PANI nanoarrays, which is beneficial for future industrial application. Keywords : MgCo2O4/PANI; Oxidative polymerization; Hydrothermal route; Oxygen evolution process. [Display omitted] [ABSTRACT FROM AUTHOR]

The Y-type hexaferrite and its nanocomposite with carbon dots have been made by using a hydrothermal approach, whereas BaSrZn 2-x Mn x Fe 12-2y Si y Ni y O 22 (x = 0.0, 0.25, 0.5, 0.75, and 1.0) was made using a conventional microemulsion process. A variety of approaches are used to explore the structural features, surface area, and morphology of the materials. As indicated by on-site substitutions and super-exchange interaction, saturation magnetization (Ms) and magnetic remanence (Mr) rise from 18 to 6 to 47.4 emu g−1 and 6.7–18.3 emu g−1, respectively with x,y = 0.75, although coercivity (Hc) declines from 1.4 to 0.39 kOe. The ferrite material's electrical resistivity enhanced from 25.85 × 106 to 49.13 × 106 Ω-cm. The increased saturation magnetization (Ms), magnetic remanence (Mr), and electrical resistance of ferrite material make it suitable for both high-density recording and microwave devices. The photocatalyst (composite) for the degradation of Rhodamine B in the presence of visible light was made from SrBaZn 1.25 Mn 0.75 Fe 10.5 Si 0.75 Ni 0.75 O 22 /CDs with different ratios. Photocatalysts with a modest CDs concentration (2.5 wt%) successfully degraded Rhodamine B (RhB) up to 94%. After eight rounds, the composite showed excellent structural stability and good reusability. The trapping experiments confirmed that OH radical species are the major contributor in the degradation process. The composite material could be used to catch visible light and purify the environment from various pollutants in the future. [ABSTRACT FROM AUTHOR]

Water electrolysis is a propitious strategy to overcome the exceeding energy crisis by producing renewable and green hydrogen fuel. However, the practical application of this process is limited due to the inadequacy of earth-rich, economical, and efficient electrocatalysts for carrying out kinetically more sluggish oxygen evolution reactions (OER). In the present research, a simple sol–gel method was employed to produce Co3O4/Pr2O3 nanocomposite material, which provides exceptional electrical conductivity and lesser charge transfer resistance of mixed-valence cations. The fabricated nanomaterials were analyzed using various scientific techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and energy dispersive X-ray spectroscopy (EDX) to determine their crystal structure, morphology, elemental composition, and oxidation states. To investigate the water oxidation capability and steadiness of the modified Co3O4/Pr2O3 electrode material in alkaline conditions, cyclic voltammetry (CV), linear sweep voltammetry (LSV), and constant current chronoamperometry (CA) were utilized. These outcomes revealed that the resultant nanocomposite exhibits a minimal overpotential around 257 mV and a lower Tafel slope around 78 mVdec−1 at a benchmark current density of 10 mAcm−2. In addition, the alkaline solution reliability of the electrocatalysts was examined and confirmed to be steady for 24 h via chronoamperometry. The extraordinary electrocatalytic achievement of Co3O4/Pr2O3 is ascribed to its structural synergistic effect, which encourages the oxygen evolution activity. [ABSTRACT FROM AUTHOR]

It is essential to produce oxygen evolution reaction (OER) electrocatalysts, which are active and enduring for water electrolyzers. In order to create the effective OER, new chromium telluride/graphitic carbon nitride (gCN/CrTe) is produced via simple hydrothermal method. In this case, catalyst super hydrophilic surface is developed by the addition of 10% gCN nanosheets that can optimize the revelation of active sites and encourage the mass dispersion. Due to the robust contact among CrTe and gCN, which causes a lattice strain and an increase in the electron density around Cr sites, regulating the bonding between the catalyst and chemical intermediates. The improved 10% gCN/CrTe nanocomposite offers not only a good endurance but also by the highest mass activity. The synthesized 10% gCN/CrTe electrocatalysts provided low overpotential around 187 mV for OER to achieve a current density of 10 mA/cm2 in alkaline media with 51.0 h of long durability. Paving the way for innovative applications, this will enable the manipulation of advanced materials' fundamental properties at the atomic scale. [ABSTRACT FROM AUTHOR]

Gadolinium (Gd) and copper (Cu) substituted MnFeO 3 nanoparticles were synthesized via sol gel auto-combustion route. In imaginary electric modulus Debye peaks occurred which indicated the phenomenon of relaxation in the given frequency range. Cole-Cole plots were taken to investigate the contribution of grain and grain boundaries. The grain boundary resistance increased as compared to grain resistance with the incorporation of Gd and Cu. Magnetization and remanence were observed to decrease while coercivity (H c) increased with Gd-Cu substitution. The phenomenon of super exchange interaction takes place between cations which reside on tetrahedral and octahedral sites. The magnetic ordering and spin canting were distorted with the substitution of Gd and Cu which leads to decrease in magnetic properties. The value of coercivity was raised upto 1992 Oe which proposed that synthesized multiferroics are useful in the fabrication of perpendicular recording media. • Gd x Mn 1−x Fe 1−y Cu y O 3 nanomaterials were synthesized via sol gel auto combustion route. • The dielectric parameters were significantly altered by Gd and Cu incorporation. • The coercivity was appreciably increased by Gd and Cu substitution. • These multiferroics may have potentials applications in recording media. [ABSTRACT FROM AUTHOR]

Supercapacitors are considered a potential source of energy conversion systems due to their advantages like high energy density, extensive cycle life, and quick charging and discharging. However, because of excessive voltage drops, they exhibit low energy density and durability. In this work, high content heteratom with various concentrations in a spinel system fabricated by hydrothermal technique. The materials were then analysed by different physical characterization methods including X-ray diffraction spectroscopy (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Using these techniques, the impact of dysprosium ions on ZnSm 2 O 4 structure and morphology was studied. Moreover, the samples were subjected to various electrochemical tests including a polarization curve (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). Among all high content heteroatom samples, 20% Dy-added ZnSm 2 O 4 displayed the highest electrochemical activity. The sample shows 1908 F g−1 specific capacitance and 1.85 Wh g−1 specific energy at 0.03 A g−1 current density. The fabricated sample also showed long term stability and shows up to 95% capacitance retention after 2000 cycles. The Dy+ doping improves compound integrity that enhances electrochemical performance. These results open a new path for the enhanced electrochemical performance in the application of supercapacitor. [ABSTRACT FROM AUTHOR]

Carbon-based materials are mostly used in supercapacitor due to control porosity, higher surface area, and easy processing for electrode production. However, it is still challenging to fabricate carbon/metal oxide-based nanocomposite electrodes with various structures and configurations for supercapacitors, particularly for miniaturized electronics. Here, in the present study, CeO2–Nd2O3/rGO ternary nanocomposite was synthesized by facial co-precipitation route, which evident enhanced capacitive performance than CeO2–Nd2O3 binary composite, bare CeO2, and Nd2O3. The rGO was homogeneously anchored on the surface of CeO2–Nd2O3 nanoparticles, forming a semi-spherical morphology. The electrochemical performance of all electrodes was investigated by different measurements. The ternary composite have a higher specific capacitance of 1265 F g−1 at 3 A g−1 current density and maintained 99% retention after 2000th cycles, showing excellent cycling performance and rate capability compared to other grown products. The excellent electrochemical pseudocapacitive performance of the ternary composite-based electrode could be ascribed due to rGO and its interfacial contact with CeO2–Nd2O3. The improved electrode conductivity generates plentiful active sites for charging and discharging and provides an easy path for the fast transportation of ions. These results open an innovative pathway for fabricating rGO and metal oxide-based composite in developing electrochemical energy storage devices for commercial production. [ABSTRACT FROM AUTHOR]