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Kumar, M. P., Sasikumar, M., Arulraj, A., Rajasudha, V., Murugadoss, G., Kumar, M. R., et al. (2022). NiFe Layered Double Hydroxide Electrocatalyst Prepared via an Electrochemical Deposition Method for the Oxygen Evolution Reaction. Catalysts, 12(11), 1470.
Abstract: Herein, we aimed to obtain NiFe layered double hydroxide (LDH) with a controlled phase and surface morphology as a highly active and stable oxygen evolution catalyst via the electrochemical deposition method, which was thermodynamically stable for the oxygen evolution reaction (OER) in an alkaline medium. The NiFe-LDH sample was analyzed by sophisticated instruments and tested as an electrocatalyst on Toray carbon (TC). The NiFe-LDH electrocatalyst showed an excellent performance with lower overpotential of 0.27 V at 35 mA cm(-2) and higher density of 125 mA cm(-2) for OER in the 1 M KOH electrolyte solution. Moreover, the prepared catalyst exhibited unpredictable long-time stability for 700 h. From our knowledge, NiFe-LDH is a robust highly stable electrocatalyst compared to the recent reports.
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Mellado, P. (2022). Intrinsic topological magnons in arrays of magnetic dipoles. Sci. Rep., 12(1), 1420.
Abstract: We study a simple magnetic system composed of periodically modulated magnetic dipoles with an easy axis. Upon adjusting the geometric modulation amplitude alone, chains and two-dimensional stacked chains exhibit a rich magnon spectrum where frequency gaps and magnon speeds are easily manipulable. The blend of anisotropy due to dipolar interactions between magnets and geometrical modulation induces a magnetic phase with fractional Zak number in infinite chains and end states in open one-dimensional systems. In two dimensions it gives rise to topological modes at the edges of stripes. Tuning the amplitude in two-dimensional lattices causes a band touching, which triggers the exchange of the Chern numbers of the volume bands and switches the sign of the thermal conductivity.
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Sepúlveda, E., Sanhueza, F., Cobo, R., Jiménez, J., & Mangalaraja, R. V. (2024). Relationship among the powder mass, press charge, and final properties of an LSGM electrolyte for solid oxide cells. MRS Adv., Early Access.
Abstract: In this work, La0.85Sr0.15Ga0.85Mg0.15O3-delta (LSGM) was prepared as an electrolyte for solid oxide cell (SOC) applications. A fast combustion method was used, starting with nitrate salts and citric acid as fuel. Different parameters, such as mass and pressing load, in the pre-sintering step were used to obtain a highly ionic conductive material at intermediate temperatures. The aim is to find optimal processing conditions for energy savings. SEM analysis showed similar grain sizes and distributions for all samples. The XRD spectra showed two main phases corresponding to LSGM orthorhombic (space group Imma) and LSGM cubic (space group Pm-3m). LaSrGaO4 appeared in lighter samples. The EIS revealed that heavier samples present high conductivity, showing a clear relationship between conductivity, sample mass (during the pre-sintering step), and the LSGM phase amount. The effect of pressure was less evident. The highest conductivity was 0.013 and 0.063 S cm-1 at 600 and 800 degrees C, respectively.
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