Role of oxygen vacancies in Co/Ni Substituted CeO2: A comparative study

• Published in: Ceramics international Vol. 45; no. 3; pp. 3823 - 3832
• Main Authors: Tiwari, Saurabh, Khatun, Nasima, Patra, N., Yadav, A.K., Bhattacharya, Dibyendu, Jha, S.N., Tseng, C.M., Liu, S.W., Biring, Sajal, Sen, Somaditya
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.02.2019
• Subjects: Bandgap; Cerium oxide; Strain; Urbach energy, Oxygen vacancies; Cerium oxide; Urbach energy, Oxygen vacancies; Strain; Bandgap
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2018.11.053

Single phase Co/Ni substituted CeO2 nanoparticles reveal the importance of oxygen vacancies on the electronic properties of the materials. The effect of Co/Ni substitution on the structural, optical, and photoluminescence properties of CeO2 have been studied systematically. Lattice shrinks and hence strain increase owing to incorporation of Co/Ni in CeO2. Optical absorption analysis shows a red shift in band-gap with Co/Ni substitution. Photoluminescence studies reveals increase in defect concentration which causes quenching of PL emission. Vibration modes at ~460 cm−1 in Raman spectra indicates incorporation of Co/Ni in CeO2 lattice whereas a broad peak appearing at ~ 540–640 cm−1 with substitution depicts the defects related to the increase in oxygen vacancy. X-ray absorption (XAS) studies show that Co/Ni substitution maintains local structure while Ce4+ → Ce3+ concentration increases to preserve the charge neutrality in lattice.