FeTiO3 Perovskite Nanoparticles for Efficient Electrochemical Water Splitting

The use of water splitting has been investigated as a good alternate for storing electrical energy. While the general interest in developing non-toxic, high-performance, and economically feasible catalysts for oxygen evolution reaction (OER) is noteworthy, there is also significant interest in water splitting research. Recently, perovskite-type oxides have performed as an alternative to non-precious metal catalysts and can act as a new class of effective catalysts in water splitting systems. Herein, a perovskite-structured FeTiO3 was prepared via a facile one-step solvothermal method using ionic liquid as templates. The results of structural and morphological studies have supported the formation of FeTiO3 perovskite. Furthermore, FeTiO3 perovskite demonstrated OER activity with a lower onset potential of 1.45 V vs. RHE and Tafel slope value of 0.133 V.dec-1 at 1 M KOH solution using mercury/mercurous oxide (Hg/HgO) were used as working electrodes. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Design and Development of Defect Rich Titania Nanostructure for Efficient Electrocatalyst for Hydrogen Evolution Reaction in an Acidic Electrolyte

Cost-effective, efficient and stable electrocatalyst for water splitting in the acidic electrolyte medium has been developed. The acidic electrolyte could be a support for the high purity hydrogen production via water splitting. Accordingly, we have prepared the defect-rich titania nanostructure via electrochemical anodization and cathodization routes using the titanium plate, which showed highly effective and durable electrocatalyst of hydrogen evolution reaction (HER) in an acidic medium. This hybrid compound showed a low onset potential of −0.17 V for HER with a current density of −150 mA cm−2 in 1 M H2SO4. Moreover, the stability test has been performed with the defect-rich titania nanostructure as cathode for 6 h in the two electrodes system. © 2021 The Author(s).The authors extend their appreciation to the Deanship of Scientific Research, King Saud University for funding this work through Research Group no RG-1441-043 and funded by the Taif University Researchers Supporting Project number (TURSP-2020/04), Taif University, Taif, Saudi Arabia. One of the author Dr G. Murugadoss would like to thank Chancellor, President and Vice Chancellor, Sathyabama Institute of Science and Technology, Chennai for providing lab facilities and encouragement

Microstructure and magnetic properties of Cu90−xCo10Nix–7.5% SmCo5 composite alloys prepared by mechanical alloying and hot pressing

Nanocrystalline composites of CuCoNi (x = 0, 10, 20 wt-%) alloys reinforced with 7.5 wt-% of intermetallic SmCo particles were prepared by several processing steps. The production of these alloys started with the synthesis of CuCoNi powder alloys by mechanical alloying of pure Cu, Co and Ni in a planetary mill for 30 h at 250 rev min. As a second step, intermetallic SmCo particles were added, and additional milling was performed for 10 h. The resulting powders of both milling processes were characterised by means of an X-ray diffraction method, a scanning electron microscopy and an electron probe microanalysis. As a final fabrication step, CuCoNi–7.5% SmCo alloy powders were consolidated by hot pressing under 88 MPa for 75 min at 750°C in an argon atmosphere. The resulting compacts are reinforced by the precipitation of Co(Ni) during consolidation, and the presence of second-phase particles of oxides and intermetallic SmCo.The authors wholeheartedly thank CONICYT of Chile for the financial support granted through FONDECYT Project 1130831 and Comisión de Ciencia y Tecnología (CICYT) of Spain under Grant number MAT2012–39124.Peer Reviewe

The effect of reaction temperature on the structural and magnetic properties of nano CoFe2O4

Nano cobalt ferrites (CoFeO) were co-precipitated at various reaction temperatures (60, 70 and 80 °C) for 1 h. The reaction temperature greatly influenced the crystallite size and the magnetic behaviours of the nano CoFeO. The mean crystallite size ranged from 9 to 15 nm with the increase in the reaction temperature and the intensity of metal oxide vibrations at 568–550 cm were also inclined. The synthesized samples were in the stoichiometric ratio of 1:2 (Co:Fe) with roughly spherical morphology. The synthesized cobalt nanoferrites exhibited ferromagnetism at room temperature and 5 K, and the saturation magnetization increased from 6.4 to 20 emu/g with the crystallite size.The authors gratefully acknowledge the FONDECYT Projects No.: 3160170, 1140195, and CONICYT BASAL CEDENNAFB0807 for the financial assistance.Peer Reviewe

The effect of calcination temperature on the structural and magnetic properties of co-precipitated CoFe2O4 nanoparticles

Cobalt ferrite (CoFeO) nanoparticles were co-precipitated from metal nitrates at the reaction temperatures of 40 and 85 °C for 1 h and were further calcinated at 500 and 800 °C for 2 h. The effect of calcination temperature on the structural, morphological, compositional and magnetic properties was investigated. Both, the reaction and calcination temperatures were significantly influenced the crystallite size and magnetic properties of cobalt ferrite nanoparticles and the crystallite size was increased with the calcination temperature. The synthesized nanoferrites were roughly in spherical morphology with the stoichiometric ratio of 1:2 Co:Fe. Co-precipitated and calcinated cobalt ferrites showed the ferromagnetism at room temperature and 5 K (−268 °C) and the saturation magnetization was increased with the calcination temperature. At low temperature, CoFeO nanoparticles calcinated at 800 °C showed the saturation magnetization of 84.36 and 92.70 emu/g for the reaction temperatures of 40 and 85 °C, respectively and the values were in accordance with the magnetization of bulk cobalt ferrites.The authors gratefully acknowledge the FONDECYT Projects No.: 3160170, 1140195, and CONICYT BASAL CEDENNAFB0807, Government of Chile for the financial assistance.Peer Reviewe

Mechanical properties of Gd-CeO2 electrolyte for SOFC prepared by aqueous tape casting

Mechanical properties of gadolinium-doped ceria (Ce0.9Gd0.1O1.95, 10GDC) green tape prepared by aqueous-based tape casting process were characterized by tensile test and shear punch test (SPT). SPT was found to be a useful method for characterizing mechanical properties of green tapes. Microstructures and mechanical properties such as flexural modulus, bending strength, and microhardness of tapes sintered at 1,300–1,500 °C have been evaluated. Indentation fracture toughness was also determined by the method of Palmqvist cracks at different applied loads for tapes sintered at 1,500 °C. Grain size measurements showed that excessive grain growth occurred during sintering despite using 10GDC nanopowders as the starting material. However, mechanical properties of sintered tapes improved by increasing sintering temperature and the results are comparable with those reported for 10GDC in literature

Development and characterization of polyvinyl alcohol stabilized polylactic acid/ZnO nanocomposites

The present work is focused on the development of polylactic acid/ZnO (PLA/ZnO) polymer nanocomposite through a melt blending route. Previously, the ZnO nanoparticles were coated with polyvinyl alcohol (PVA) via a solvothermal method. The morphology of PVA coated ZnO nanostructures and the formation of polymer nanocomposites were identified through transmission electron microscopy analysis. Thermogravimetric analysis showed that PVA coated ZnO(c) nanoparticles incorporated into the PLA matrix exhibited better thermal stability, suggesting that PVA could be acting as a strong stabilizing agent for ZnO nanoparticles. The tensile strength, elastic modulus, strain at maximum strength and the maximum strain were extracted through stress-strain relations.CONICYT PAI 781411004 CONICYT-REGIONAL PRFC0002-CIPA Programa de Financiamiento Basal para Centros Cientificos y Tecnologicos de Excelencia PFB-2