Synthesis of High Quality LaCoO3 Crystals Using Water Based Sol-Gel Method

Abstract

Lanthanum cobaltite (LaCoO 3 ) crystalline material is a promising material for its interesting electrical, magnetic, catalytic and thermoelectric properties. In this study, LaCoO 3 powders were synthesized by water based sol-gel method using metal nitrates as precursors and citric acid as the chelating agent at room temperature. The dried powders were amorphous and their thermal decomposition occurs stepwise upon heating to 400 °C. Pure perovskite-type single phase LaCoO 3 polycrystals are formed after heating at 600 °C. The pallets prepared from calcined powers were sintered at 1200 °C and crystalline pallets were characterized for investigation of electrical, optical and thermoelectric properties. The obtained results revealed that the prepared samples were highly crystalline with large cation ordering. The sol-gel method found to be efficient for much production of a lot of crystalline transition metal oxides at low cost.

Constructing LaxCoyO3 Perovskite Anchored 3D g-C3N4 Hollow Tube Heterojunction with Proficient Interface Charge Separation for Stimulating Photocatalytic H2 Production

“…Likewise, the existence of the La–O bond is indicated by the shoulder peak positioned at 423 cm –1 . Moreover, the band of the FTIR spectra at 1627, 1550, 1213, 1102, and 1497 cm –1 are associated with the LaCoO 3 lattice vibration . The dip appearing at 3747 cm –1 corresponds to the asymmetric and symmetric OH bending of water.…”

Structural, electronic, and magnetic properties of bulk and epitaxial LaCoO3 through diffusion Monte Carlo

“…The QE-RRKJ PBE0 band gap is in very good agreement with the CRYSTAL-LCAO, again indicating an estimate that is 0.8 eV larger than the VASP-PAW PBE0 band gap. The hybrid-DFT band gap values are rather large compared to some of the experiments claiming 0.6-0.9 eV from photoemission measurements [110,111], and at 0.1-1.1 eV from optical conductivity measurements [112][113][114]. However, the recent photoluminescence and UV-Vis spectroscopy measurements yield a gap of nearly 3.5 eV which agrees very well with the CRYSTAL-LCAO and QE-RRKJ PBE0 calculations.…”

“…In addition to the coexisting Co 3 O 4 phase, the material may also have significant intrinsic defects in the powder form. In Section III C, we discuss that photoemission and optical conductivity measurements yield a much smaller band gap compared to the Kohn-Sham gaps from DFT functionals [110][111][112][113][114]. It is known that oxygen vacancies can change the charge state of Co atoms, modifying the magnetic structure of LCO.…”

Alternative pathways to α,β-unsaturated ketones via direct oxidative coupling transformation using Sr-doped LaCoO 3 perovskite catalyst

“…Another absorption peak at 420 cm −1 (not shown here) marks the formation of O-Co-O and La-O-Co, indicating that LaCoO 3 structure was generated [53]. The strong absorption peak at 1454 cm −1 is due to the vibrations of the lanthanum cobaltite crystal lattice [54].…”

“…Another absorption peak at 420 cm −1 (not shown here) marks the formation of O–Co–O and La–O–Co, indicating that LaCoO 3 structure was generated [53]. The strong absorption peak at 1454 cm −1 is due to the vibrations of the lanthanum cobaltite crystal lattice [54]. A band at 667 cm −1 was observed on the sample, assigned to Co 3 O 4 , which was generated due to strontium doping in the perovskite [55].…”