Temperature Dependence of Band Gap of Ceo2 Nanoparticle Photocatalysts

Abstract

Cerium dioxide (CeO2) have been one of the attractive photocatalysts material in recent years. Band gap and its change with temperature takes remarkable attention in the photocatalytic applications. The present work re-ported structural and temperature-dependent band gap characteristics of the CeO2 nanoparticles on glass sub-strate. X-ray diffraction (XRD) pattern exhibited nine peaks related to face-centered cubic structure. Crystallite size and micro-strain of the nanoparticles were determined from the analyses of XRD peaks. Scanning electron microscope (SEM) image indicated that CeO2 is in the form of nanoparticle with almost cube shaped of diameters in between 20 and 30 nm. Transmission measurements were performed in the 350-700 nm range at various temperatures between 10 and 300 K. The analyses of the transmission spectra showed that direct band gap energy decreases from 3.35 to 3.29 eV when sample temperature was raised from 10 K to room temperature. The temperature dependence of band gap energy was analyzed by Varshni expression. The analysis presented ab-solute zero and rate of change of band gap with temperature as 3.35 eV and-4.7 x 10-4 eV/K, respectively.