Glycine Nitrate Research Articles

High-pressure behavior of high-entropy A2B2O7 pyrochlore

A single high-entropy pyrochlore-type compound (A2B2O7) was successfully synthesized, incorporating 8 different rare-earth cations at the A site and 2 different metal cations at the B site in equiatomic amounts [(8A1/8)2(2B1/2)2O7]. Powders with a nominal composition of (La1/8Sm1/8Nd1/8Pr1/8Y1/8Gd1/8Dy1/8Yb1/8)2(Hf1/2Zr1/2)2O7 were fabricated by glycine nitrate procedure (GNP). The GNP process yielded powders with low crystallinity and after subsequent calcination, a well crystalline ceramic powders were formed. The phase evolution was initially analyzed using X-ray diffraction (XRD). In situ high-pressure X-ray diffraction was employed to investigate the structural stability and high-pressure behavior of the A2B2O7 pyrochlore up to 25.8 GPa. Theoretical investigations of the high-entropy pyrochlore systems were performed and showed good agreement with the experimentally obtained results.

Exploring a New, Scalable Synthesis Route to Disordered Rock Salt (DRX) Cathode Materials

The global demand for lithium-ion batteries (LIBs) is ever-increasing as many nations seek to achieve a net carbon neutrality by the late 2030s. LiNi x Mn y Co1–x–y O2, (NMC) is one of the most widely-used Li-ion cathode active materials. Despite its excellent performance (e.g., reversible capacities up to ~220 mA h g–1 and 500+ cycles), NMC contains both Ni and Co, which are expensive and have vulnerable supply chains. Li-excess disordered rock salt (DRX) materials are promising new cathode materials that utilize earth-abundant transition metals such as Mn and Ti. Through a combination of cationic and anionic charge compensation, DRX materials can attain specific energies ≥700 Wh kg–1. Doping F– into the DRX structure (Li1+x Mn y Ti2–1–x–y O2–z F z ) has been reported to improve the material’s cycling stability. Despite their promising properties, most DRX cathodes are prepared through solid-state synthesis routes which require high-energy milling, provide little-to-no control over the particle morphology, and are difficult to scale.In this work, we developed a scalable combustion synthesis route (the glycine nitrate process) to produce high purity, high performance DRX cathodes. More specifically, we prepared two DRX precursors with nominal compositions of Li1.2Mn0.5Ti0.3O1.95 and Li1.2Mn0.7Ti0.1O1.85. When the precursors were heated under Ar to 1000 °C for 1 – 4 h, only 50% Li1.2Mn0.5Ti0.3O1.95 adopted a DRX structure, and no DRX formed for Li1.2Mn0.7Ti0.1O1.85. However, adding LiF to the precursors facilitates DRX phase formation during annealing and yields high purity DRX powders with the nominal compositions Li1.25Mn0.5Ti0.3O1.95F0.05 and Li1.35Mn0.7Ti0.1O1.85F0.15. In situ X-ray diffraction was employed to study the synthesis process, revealing DRX begins to form at just 600 °C, which is much lower than traditional solid-state routes. Furthermore, electrochemical tests on the Li1.35Mn0.7Ti0.1O1.85F0.15 cathode reveal these materials attain excellent performance with initial reversible capacities up to 215 mA h g–1 and stable cycling performance. These promising results demonstrate that combustion synthesis is a viable method for the scale-up of DRX materials.This research was conducted at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) and was sponsored by the Vehicle Technologies Office (VTO) under the Office of Energy Efficiency and Renewable Energy (EERE). Some measurements were conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility.

Modulated magnetostriction and multiferroic properties in the PVDF-based cobalt ferrite particulate composites

Multiferroic materials (MFM) have drawn substantial attention for developing smart magnetodielectric devices. Herein, cobalt ferrite CoFe2O4 (CFO) was synthesized by a glycine–nitrate sol-gel auto-combustion route and, PVDF-based particulate composite films embedded with CFO have been developed. A comprehensive investigation evaluated the effects of magnetostriction, initiated from the embedded CFO phase, on magnetodielectric characteristics of composite films. The structural, electrical, magnetostrictive and magnetodielectric properties were investigated. The embedded CFO particulate endows PVDF matrix at a higher β–phase forming ability, which enhances the ferroelectricity with a polarisation (Pmax∼1.09 μC/cm2@ 850 kV/cm), a higher dielectric constant (εr∼12.33) and lower dielectric loss. The typical magnetic hysteresis loop was obtained with saturation magnetization (MS∼4.96 emu/g) and coercivity (HC∼1.49 kOe), revealing the ferromagnetic ordering in composite films. The response of the magnetodielectric (MD) is observed at room temperature, that is, a large negative MD coefficient ∼2.1 % @ Hcr∼5.0 kOe is achieved for Co0.9Fe2.1O4/PVDF composite films, while MD∼0.65 %@ Hcr∼1.0 kOe is obtained for Co1.1Fe1.9O4/PVDF films, accompanied by a maximum MD∼4.35 % at resonance frequency. The variation in the MD performance reveals a close correlation to the modulated magnetostriction, such as the magnetocrystalline anisotropy, field-induced coefficient and magnetostrictive susceptibility, indicating the strain-mediated coupling MD effect. The multiferroic properties in CoxFe3–xO4/PVDF composites have potential for magneto-dielectric sensing applications. Furthermore, this work would be exploited to understand MD coupling mechanism and develop MFM for multifunctional devices.

Dry Reforming of Methane over Pyrochlore-Type La2Ce2O7-Supported Ni Catalyst: Effect of Particle Size of Support.

The properties of supports (such as oxygen vacancies, oxygen species properties, etc.) significantly impact the anti-carbon ability due to their promotional effect on the activation of CO2 in dry reforming of methane (DRM). Herein, pyrochlore-type La2Ce2O7 compounds prepared using co-precipitation (CP), glycine nitrate combustion (GNC) and sol-gel (S-G) methods, which have highly thermal stability and unique oxygen mobility, are applied as supports to prepare Ni-based catalysts for DRM. The effect of the calcining temperature (500, 600 and 700 °C) on La2Ce2O7(CP) has also been investigated. Based on multi-technique characterizations, it is found that the synthesis method and calcination temperature can influence the particle size of the La2Ce2O7 support. Changes in particle size strongly modulate the pore volume, specific surface area and numbers of surface oxygen vacancies of the La2Ce2O7 support. As a result, the distribution of supported Ni components is affected due to the different metal-support interaction, thereby altering the activity of the catalysts for cracking CH4. Moreover, the supports' abilities to adsorb and activate CO2 are also adjusted accordingly, accelerating the removal of the carbon deposited on the catalysts. Finally, La2Ce2O7(CP 600) with an appropriate particle size exhibits the best catalytic activity and stability in DRM.

Low temperature glycine nitrate combustion synthesis of nanostructured zinc ferrites for enhanced visible light-driven methylene blue degradation

Low temperature glycine nitrate combustion synthesis of nanostructured zinc ferrites for enhanced visible light-driven methylene blue degradation

Electrochemical performance of Pr0.6Sr0.4Fe0.8Co0.2O3−δ as potential cathode material for IT-SOFC

Solid oxide fuel cells (SOFCs) are renowned for being effective energy sources that have potential to influence how energy is developed in future. SOFCs operate at low temperatures provides different benefits for widespread commercialization. In the present study a perovskite material Pr0.6Sr0.4Fe0.8Co0.2O3−δ (PSFCo) was investigated as cathode for SOFC in intermediate temperature range. Glycine nitrate process was used for the preparation of the samples. PSFCo exhibited cubic structure having small particle size (100–200 nm). The electrical conductivity of the PSFCo was measured as function of temperature up to 850 ℃. The sample displayed maximum electrical conductivity of 370 Scm−1 at around 550–600 ℃. The polarization behavior of PSFCo was calculated by means of AC impedance with Sm0.8Ce0.2O2 (SDC) as electrolyte. The value of area specific resistance (ASR) was calculated as 0.146 Ωcm2 at 800 ℃ and 0.248 Ωcm2 at 700 ℃.

ZnCrXFe2-XO4 (X = 0–2) porous powder prepared through self-combustion glycine nitrate process and applied to methyl alcohol steam reforming for production of pure hydrogen

Climate change, global warming, and energy crisis have become an important problem due to the environmental impact of fossil fuels. Hence, alternate energy source is needed for environmental remediation. One such source could be hydrogen (H2). H2 is used as an alternate energy carrier due to it is non-toxic, clean, and efficient. Steam reforming of methyl alcohol (or) methanol (SRM) is a widely available and low-cost hydrogen production method. In this stream-reforming process, mostly commercial zinc-supported catalyst is used, these have some economic defect. Therefore, we need to find alternate suitable catalysts for the SRM process. In this study, ZnCrXFe2-XO4 (X = 0–2) porous catalyst powders of different ratios were synthesized by the glycine nitrate process (GNP) for hydrogen production by SRM. The specific surface areas of the ZnCrXFe2-XO4 powders ranged from 15.75 m2/g to 45.16 m2/g. The ZnCr0.4Fe1.6O4 powder had the highest H2 production without activation, reaching 6850.33 ml STP min−1 g-cat−1 at a reaction temperature of 450 °C. ZnCr0.4Fe1.6O4 porous powders prepared using the GNP method have simple, rapid process steps, low cost, high catalytic activity, and they can be applied to hydrogen fuel cells or other related catalysis applications in the future. The pure hydrogen production performance of these ZnCrXFe2-XO4 catalysts could be of great importance in industry and economic impact.

Exploring the role of fuel in the synthesis of bismuth ferrite nanoparticles by microwave-assisted combustion in solid state and the study of photocatalytic degradation of Brilliant Blue

The current research focused on the synthesis of bismuth ferrite nanoparticles using the method of microwave-assisted combustion in the solid state. The starting materials employed in the synthesis included bismuth nitrate pentahydrate, Bi(NO3)3·5H2O, and iron (III) nitrate nonahydrate, Fe(NO3)3·9H2O, with a 1:1 molar ratio and as an organic driving agent ammonium nitrate, (NH4) (NO3), along with various fuels such as glycine, urea, acetamide. The reaction conditions were optimized to achieve the desired BiFeO3 nanopowder, by using the molar ratio of glycine and ammonium nitrate as fuel and an irradiation power of 360 and 900 W for 20 min. Furthermore, the synthesized nanoparticles by 360 W were analyzed for their photocatalytic performance in the degradation of the organic dye Brilliant Blue as a pollutant.

Y doped La2Ce2O7 proton conducting SOFC electrolyte membrane: Thin film deposition via EPD, electrochemical performance and DRT analysis

Herein, a new series La2-xYxCe2O7 (x = 0, 0.05, 0.10, 0.15 and 0.20) as electrolyte materials are investigated for intermediate temperature SOFCs application. The adopted synthesis route for nano sized La2-xYxCe2O7 powder is glycine nitrate combustion. The crystal structure and phases present in the Y doped La2Ce2O7 is studied extensively using X-ray diffraction and Raman spectroscopy. The material exhibits dual phase fluorite (F) type and C type phases. The structural relationship along with oxygen vacancies are critically analyzed. The ionic conductivity of the Y doped La2Ce2O7 series are studied and La1.85Y0.15Ce2O7 exhibits the highest ionic conductivity of 3.29 × 10−3 Scm−1 in moist atmosphere at 700 °C. The stability and suspension chemistry of La1.85Y0.15Ce2O7 is investigated in different suspension media and then electrophoretic deposition (EPD) employed to fabricate the thin (∼13 μm) and dense electrolyte on the fuel electrode. The cell demonstrated a maximum power density (MPD) of roughly 500, 353.6, and 197 mW cm−2 at 700 °C, 650 °C, and 600 °C, respectively. The cell is found to be stable under constant operation of short-term stability test at 700 °C. The distribution of relaxation time (DRT) from the impedance spectra suggests that the gas diffusion process in the electrodes contributes greatly to the overall polarization of the cell.

Thin Film Fabrication and Characterization of LSM-YSZ/YSZ Half-Cell for Solid Oxide Electrolysis Cell via Screen-Printing

Green or renewable energy is important to attain a sustainable low carbon economy and the use of hydrogen has been an alternative solution for the unreliable continuous supply of these energy sources. Solid oxide electrochemical cells is a promising technology for hydrogen generation in which the LSM-YSZ is one of the important component materials for this application. In this study, LSM-YSZ will be deposited on the YSZ substrate via screen-printing. Screen-printing is an easy and simple set-up that offers film quality control. Specifically, the study aimed to deposit a porous LSM-YSZ thin film, as well as to determine the effect of the particle size of the starting powders on the quality of the deposited film. Two synthesis methods for the powders were utilized before screen printing, the solid-state reaction (SSR) ball milling, and the glycine nitrate process (GNP). Results showed that a porous and even thin film with uniform distribution of LSM and YSZ was obtained after the screen printing. Moreover, the GNP powders produced a smaller particle size, a more porous morphology, and a thinner film when screen-printed compared to the SSR ball milled.

Screen-Printing of NiO-ScSZ on YSZ Substrate Using Solid-State Reaction and Glycine-Nitrate Process Precursors for Solid Oxide Electrochemical Cells

Solid oxide electrochemical cells (SOCs) consisting of solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) are widely studied for the development of high-efficiency energy generation and storage devices. To investigate the effect of precursor particle size on the microstructural and morphological properties of the electrode, glycine nitrate process and solid-state reaction ball-milling were utilized as synthesis methods for Nickel oxide-scandia stabilized zirconia (NiO-ScSZ) powders. The synthesized powders were then screen-printed on commercial YSZ solid electrolyte substrates. The structure and morphology of the sintered electrodes were investigated. Particle size analysis (PSA) revealed that NiO-ScSZ precursor powders obtained from GNP ball-milled had a smaller average particle size than solid-state reaction ball-milled powders. For the sintered NiO-ScSZ films, cubic structures of both NiO and ScSZ have been observed from the X-ray diffraction (XRD) patterns. A better porous morphology with less agglomeration and better dispersion of NiO and ScSZ phases was revealed by the scanning electron microscopy (SEM) micrographs and elemental mapping for the GNP-ball-milled synthesized powders.

Ceramics of the Cs2O–Al2O3 System Prepared by Solid-Phase Technology and the Glycine–Nitrate Combustion Process

Cs2O–Al2O3 ceramic samples containing 20 and 33 mol % cesium oxide were prepared by сeramic technique and by the glycine–nitrate combustion process. The prepared samples were identified and characterized by X-ray powder diffraction and X-ray fluorescence analyses, scanning electron microscopy, and differential thermal analysis. X-ray powder diffraction and scanning electron microscopy showed that the phase composition and surface of the samples change significantly and nonmonotonically depending on the synthetic method used and the heat treatment parameters of the batch. Optimal synthetic conditions and heat treatment parameters for preparing Cs2O–Al2O3 samples were elucidated.

Ceramics of the Cs2O–Al2O3 System Prepared by Solid-Phase Technology and the Glycine–Nitrate Combustion Process

Ceramics of the Cs2O–Al2O3 System Prepared by Solid-Phase Technology and the Glycine–Nitrate Combustion Process

Erbium-Doped Lu2O3-MgO and Sc2O3-MgO IR-Transparent Composite Ceramics.

Novel IR-transparent ceramics of erbium-doped Lu2O3-MgO and Sc2O3-MgO composites have been successfully obtained using a combination of glycine-nitrate self-propagating high-temperature synthesis and vacuum hot-pressing methods. Composites have densities greater than 99.5% of those calculated by X-ray diffraction and consist of uniformly distributed submicron grains of magnesium and rare earth oxides. The transmittances of 1.5 mm thick composites are as high as 84.5% and 78.9% at ~5 µm for Er:Lu2O3-MgO and Er:Sc2O3-MgO, respectively. Both composites are favorable matrices for doping with erbium ions, which exhibit intense luminescence in the visible, near, and mid-IR under relevant excitation. The position of the luminescence bands is similar to Er:Lu2O3 and Er:Sc2O3 ceramics; the lifetimes of the 4I13/2 state are 8.85 ± 0.1 ms and 5.7 ± 0.2 ms for 3%Er:Lu2O3-MgO and 3%Er:Sc2O3-MgO, respectively.

Magnetically Separable Mixed-Phase α/γ-Fe2O3 Catalyst for Photo-Fenton-like Oxidation of Rhodamine B

Iron oxides are widely used as catalysts for photo-Fenton-like processes for dye oxidation. In this study, we report on the synthesis of an α/γ-Fe2O3 mixed-phase catalyst with magnetic properties for efficient separation. The catalyst was synthesized using glycine–nitrate precursors. The synthesized α/γ-Fe2O3 samples were characterized using scanning electron microscopy, X-ray diffraction spectroscopy (XRD), Raman shift spectroscopy, X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM). The diffraction peaks were indexed with two phases, α-Fe2O3 as the main phase (79.6 wt.%) and γ-Fe2O3 as the secondary phase (20.4 wt.%), determined using the Rietveld refinement method. The presence of Fe2+ was attributed to oxygen vacancies. The mixed-phase α/γ-Fe2O3 catalyst exhibited remarkable photo-Fenton-like degradation performance for Rhodamine B (RhB) in neutral pH. The effects of operating parameters, including H2O2 concentration, catalyst concentration, and RhB concentration, on the degradation efficiency were investigated. The removal rates of color were 99.2% after 12 min at optimal conditions of photo-Fenton-like oxidation of RhB. The sample exhibited a high saturation magnetization of 28.6 emu/g. Additionally, the α/γ-Fe2O3 mixed-phase catalyst showed long-term stability during recycle experiments, with only a 5% decrease in activity.

Luminescence and protonic conduction of Eu3+ doped BaCeO3 perovskite synthesized by glycine-nitrate combustion method

The Eu3+ doped barium cerate had been made using the Glycine nitrate combustion technique. The prepared powder's characterization reveals that it is made entirely of orthorhombic nanopowder that has been crystallized. The generated nanopowder's emission spectra were used to calculate the Judd-Ofelt parameter intensities, which confirmed that the added Eu3+ replaced the Ce4+ in the perovskite structure and that it was positioned in the 4b, non-centrosymmetric Wyckoff position. By using complex impedance spectroscopy, the produced nanopowder's electric characteristics were investigated in the temperature range of 480–650 °C (CIS). The obtained doped barium cerate has an unusual activation energy (0.28 eV between 562 and 650 °C) and conductivity of 2673 10−5 Ω−1 cm−1 at 650 °C in the temperature range under consideration.

ZnO-ZnFe2O4 Catalyst for Hydrogen Production from Methanol Steam Reforming

In this study, ZnFe2O4 and ZnO-ZnFe2O4 catalysts were prepared using the glycine–nitrate process (GNP). The prepared ZnFe2O4 and ZnO-ZnFe2O4 catalyst powders were characterized using a scanning electron microscope, transmission electron microscope, XRD diffraction studies, and selected area diffraction pattern studies. In addition, the specific surface area was measured using a Brunauer–Emmett–Teller specific surface area analysis. The hydrogen reduction in different temperature ranges was analyzed using the H2 temperature-programmed reduction technique. The specific surface area of the ZnFe2O4 was 5.66 m2/g, and the specific surface area of the ZnO-ZnFe2O4 was 8.20 m2/g at a G/N ratio of 1.5 and at a G/N ratio of 1.7, respectively. The specific surface area of the ZnFe2O4 was 6.03 m2/g, and the specific surface area of the ZnO-ZnFe2O4 was 11.67 m2/g. The ZnFe2O4 and ZnO-ZnFe2O4 were found to have the best catalytic effect at 500 °C. In particular, the highest H2 generation rate of the ZnO-ZnFe2O4 (GN = 1.7) at 500 °C was 7745 mL STP min−1 g-cat−1. Moreover, the ZnO-ZnFe2 O4 catalyst demonstrated good H2 selectivity and stability during the process of steam reforming methanol. Therefore, the ZnO-ZnFe2O4 catalyst powder exhibited high catalytic activity due to the good dispersibility of the ZnO, which increased the specific surface area of the catalyst. In the future, the catalyst can be applied to the steam reforming of methanol for industrial purposes.

Optimization of Culture Conditions for Gibberellic Acid Production by Fusarium solani KUSF0301

The current study reports the effect of various cultural parameters on the gibberellic acid (GA) by Fusarium sp. isolated from an agricultural field of Murshidabad district in West Bengal, India. Gibberellin is one of the principal plant growth regulators that influence the overall developmental processes in angiosperms. The Fusarium sp. was isolated by soil dilution plate technique on selective pentachloronitrobenzene (PCNB) medium. The isolate was identified and subsequently characterized by the routine morphological studies and molecular analysis. Various physiological parameters viz., growth media, carbon and nitrogen sources, incubation temperature and pH of the culture medium were taken into consideration for determining their effect on the phytohormone production and subsequent optimization of the culture conditions. GA production was found to be highest in CD broth. Among the carbohydrate sources used, sucrose (7300 µg/ml), dextrose (7150 µg/ml) and maltose (6650 µg/ml) were found to be most conducive for GA production. Among the nitrogen sources, glycine (7360 µg/ml) and sodium nitrate (7250 µg/ml) were found to be most stimulatory in GA production. Interestingly, with the increase in pH, GA production was also found to be increased. Maximum GA production was recorded at pH 10 (7800 µg/ml). GA production was found equally well in temperature range 14-32°C (7000-7160 µg/ml).

Synthesis of hollow spherical WO3 powder by spray solution combustion and its photocatalytic properties

Hollow spherical WO3 powder was prepared from mixed solution of ammonium metatungstate, glycine and ammonium nitrate by spray solution combustion synthesis (SSCS) method. The effects of fuel ratio, temperature, precursor solution concentration on the structure and morphology of as-prepared powder, and the SSCS mechanism have been discussed in detail. When precursor solution concentration is 0.10 mol/L, in which the fuel ratio is 2, and reaction temperature set to be 800 °C, the spherical WO3 powder with smooth surface and a median diameter of 24.02 μm can be obtained, which consists of particles with a diameter of about 30 nm, and the specific surface area is 13.5 m2/g. Moreover, the as-synthesized WO3 powder is applied to degrade RhB solution in visible light to evaluate its catalytic performance by PLS-SXE300/300UV. Only 10 mg powder can degrade 70.1% RhB solution within 2 h.

Effects of roller speed on the structural and electrochemical properties of LiCo0.6Sr0.4O2 cathode for solid oxide fuel cell application

The solid oxide fuel cell (SOFC) is one of the most anticipated green and sustainable energy technologies. Numerous considerations and ongoing studies into the basic elements of technology make its commercialization challenging, especially since a particular functional reaction necessitates a system with a certain microstructure. For instance, the microstructure can be modified by improving the oxidation reduction process to form cathode material (ORR). The glycine nitrate combustion technique produces LiCo0.6Sr0.4O2 (LCSO) cathodes and the slurry production is characterized by the aim of decreasing the area specific resistance (ASR) of the symmetrical cell and accelerating the ORR process for application in IT-SOFCs. Then, a predefined process with the triple roll milling technique is used to alter the process character, producing slurries/inks of differing characteristics. Field emission scanning electron microscopy (FESEM) analysis of the surface and cross section showed the uniformity and strong adhesion of the film to the substrate. When the speed parameter was varied between 300 and 500 rpm, the lowest ASR value of 16.17 Ω cm2 was obtained using the LCSO ink processed at 300 rpm. In addition, this study validates the importance of processing technique as a key parameter discovered by the study for optimizing the electrochemical performances.