A Comparative Study of Visible Raman Scattering of Ceria Prepared by Sol-gel and Hydrothermal Techniques with Gold Nanoparticles

Enhanced Ionic Conductivity and Durability of Novel Solid Oxide Fuel Cells by Constructing a Heterojunction Based on Transition and Rare Earth Metal Co-doped Ceria

“…The sharpest peak at ∼450 cm –1 is attributed to triply degenerate F 2g Raman mode for cubic fluorite ceria with a space group of Fm3m , which is generated by the symmetric stretching mode of oxygen ions around cerium cations . Generally, the F 2g vibration mode possesses a Raman peak at ∼460 cm –1 for bulk ceria samples; ,, thus, the red-shift of the prominent peak here indicates the effective dopant of nickel ions and gadolinium ions into the ceria lattice. , The further red-shift of the tested powders is probably due to the temperature (causing size changes) and strain effects . Transverse optical (TO) phonon mode is detected at ∼230 cm –1 , suggesting that the samples display Raman activity due to the lattice distortion caused by the ceria doping, , while longitudinal optical (LO) mode is detected at ∼110 cm –1 .…”

“…To distinguish the functional groups and the vibrational properties of the synthesized materials from micro perspectives, Raman spectra and FTIR spectra were obtained on samples before and after the test. Ceria-based samples have variations of defects, especially for oxygen defects, which are sensitive to UV light and Raman resonance . The Raman spectra of 7GNDC-3SnO 2 raw powders (black line) show several Raman peaks centered at 110, 236, 448, and 550 cm –1 , whereas peaks of tested samples (red line) are at 109, 228, 446, and 566 cm –1 (seeing Figure ).…”

“…Ceria-based samples have variations of defects, especially for oxygen defects, which are sensitive to UV light and Raman resonance. 42 The Raman spectra of 7GNDC-3SnO 2 raw powders (black line) show several Raman peaks centered at 110, 236, 448, and 550 cm −1 , whereas peaks of tested samples (red line) are at 109, 228, 446, and 566 cm −1 (seeing Figure 6). The sharpest peak at ∼450 cm −1 is attributed to triply degenerate F 2g Raman mode for cubic fluorite ceria with a space group of Fm3m, which is generated by the symmetric stretching mode of oxygen ions around cerium cations.…”

“…46,47 The further red-shift of the tested powders is probably due to the temperature (causing size changes) and strain effects. 42 Transverse optical (TO) phonon mode is detected at ∼230 cm −1 , suggesting that the samples display Raman activity due to the lattice distortion caused by the ceria doping, 25,44 while longitudinal optical (LO) mode is detected at ∼110 cm −1 . 47 The less prominent Raman band observed at ∼550 cm −1 is assigned to the defect band (D band), which originated from the dopant of extrinsic cations and induced oxygen vacancies.…”