In situ variable temperature X-ray diffraction studies on the transformations of nano-precursors to La–Ni–O phases

Continuous Hydrothermal Synthesis of Inorganic Nanoparticles: Applications and Future Directions

“…To better understand the solid-state transformations that were occurring between the lanthanum hydroxide and nickel hydroxide NPs, the authors investigated an in situ VT-XRD study. 538 Because of the use of a platinum strip resistive heater, the results were not consistent with previous results obtained via muffle furnace heating of the precursors (likely to be due to differences in oxygen partial pressures). However, notably the synthesis of La 2 NiO 4−δ was achieved directly from the hydroxide nanoprecipitates at a heat-treatment temperature of only 700 °C (both in air and in argon), which was the lowest synthesis temperature for this phase reported to date.…”

“…To better understand the solid-state transformations that were occurring between the lanthanum hydroxide and nickel hydroxide NPs, the authors investigated an in situ VT-XRD study . Because of the use of a platinum strip resistive heater, the results were not consistent with previous results obtained via muffle furnace heating of the precursors (likely to be due to differences in oxygen partial pressures).…”

“…Altogether, they offer significant environmental advantages over conventional power generation methods. With relevance to the applications of different types of fuel cells, the authors will initially focus on solid oxide fuel cells (SOFCs). ,,,,, There have been some initial reports on the CHFS of nanomaterials that might be suitable as components in SOFCs. The authors envisage that other fuel cells such as Polymer Electrolyte Membrane Fuel Cells (PEMFCs) might also be able to benefit from the use of metal oxide or metal NPs made via CHFS for improving performance (for oxygen reduction or oxygen evolution reactions, respectively).…”

“…In the aforementioned La–Ni–oxides, ,, the structures were based on doped/undoped alternating perovskite and rock-salt layers, which alter the balance of electronic and ionic conductivity. However, the perovskite structure itself can be doped to make mixed ion conductors, which contain large amounts of anion vacancies (that can enhance oxygen conductivities; see above for SOFC cathodes).…”

Low Temperature Formation of Ruddlesden–Popper‐Type Layered La2CoO4±δ Perovskite Monitored via In Situ X‐ray Powder Diffraction

“…Diffraction patterns showed the presence of impurities such as La 2 O 3 . In addition, Weng et al achieved the formation of La 2 NiO 4 via a continuous hydrothermal flow synthesis (CHFS) after heat treatment at 700 °C for 3 h which was claimed to be the lowest temperature used for the synthesis of La 2 NiO 4 . In fact, the synthesis of an RP‐type perovskite can be rather challenging, depending on the desired chemical composition.…”