Escobar Cano, GiamperGiamperEscobar CanoBrinkmann, YannickYannickBrinkmannZhao, ZhijunZhijunZhaoKißling, PatrickPatrickKißlingFeldhoff, ArminArminFeldhoff2024-02-202024-02-202022-09-24Crystals 12 (10): 1346 (2022)https://hdl.handle.net/11420/45828La₂NiO₄+δ particles with a plate-like morphology were prepared from a NaOH melt by molten-flux synthesis. For this purpose, the intermediates from a sol–gel process were used as reactants. Using powder X-ray diffraction, the sol–gel intermediates were identified as a mixture of tetragonal La₂O₂CO₃ and cubic NiO. The existence of NiO was also confirmed by transmission electron microscopy in combination with electron-energy loss spectroscopy. The ultrafine mixed sol–gel intermediates were then mixed with NaOH powder and additional water in a nickel crucible and heated to 673 K for 8 h. The chemical reactions in the air during the molten-flux synthesis and the influence of the salt on the formation of La₂NiO₄+δ were examined by thermogravimetric analysis. The powder X-ray diffraction indicated a K₂NiF₄-type tetragonal structure with the I4/mmm space group for the reaction product. The scanning electron microscopy showed plate-like La₂NiO₄+δ crystals with a length and thickness of approximately 9 µm and 2 µm, respectively, while the energy-dispersive X-ray spectroscopy revealed a homogeneous distribution of lanthanum and nickel in the product powder. The influence of the processing parameters on the product generation, as well as on the size and morphology of the La₂NiO₄+δ particles, was systematically studied.en2073-4352202210MDPI AGcrystal growthcrystal morphologyLa₂NiO₄+d |molten-flux synthesisNaOH meltsol–gel processChemistryJournal Article10.3390/cryst12101346Journal Article