Sol-gel Synthesis and Characterization of Lithium and Cerium Codoped Perovskite

Abstract

Perovskites are an important group of ceramic materials with a structural formula ABO3 and wide array of potential applications in electronics, superconductors, catalysis, etc. CaTiO3, by which the whole group was named for, is particularly significant due to its use in catalysis, but its photocatalytic activity is limited by a large band gap value (~3.5 eV). A possible solution is the substitution of A and B cations with foreign cations which causes the alteration of properties, including photocatalytic efficiency. The aim of this work was the sol-gel synthesis of lithium and cerium codoped CaTiO3, characterization of the prepared gel and ceramics obtained by its thermal treatment. Samples of codoped perovskite, Ca1-xLixCexTiO3, where x = 0, 0.01, 0.02, 0.03 and 0.04, were prepared and characterized using powder X–ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), differential thermal and thermo-gravimetric analysis (DTA-TGA), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Photocatalytic activity was evaluated through the study of methylene blue photocatalytic degradation. XRD analysis showed that the prepared samples consisted of calcium nitrate and titanium chelate. In accordance with the established thermal evolution path, all samples were thermally treated at 500 °C for 2 hours. Beside perovskite, Ca2Ti2O6 appeared as a secondary phase in all thermally treated samples. SEM analysis of thermally treated samples showed the presence of agglomerates of irregular morphology and the decrease of primary particles size with the increase of dopants concentration. The sample with x=0.04 showed an increased photocatalytic activity.

Perovskite Oxide–Based Materials for Photocatalytic and Photoelectrocatalytic Treatment of Water

“…Several researchers have reported titanate-based perovskite with heterostructure and co-doping. A majority of them have demonstrated an excellent photocatalytic performance as compared to their bare samples, and this is due to reduced bandgaps and efficient migration of charge pairs, hence reduced recombination rate which produces great catalytic activity within the redox reaction (Rosy and Kalpana, 2018;Jiang et al, 2019;Abdi et al, 2020;Chen X. et al, 2020;Dong et al, 2020;Han et al, 2020;Mužina et al, 2020;Tomar et al, 2020;Xiao et al, 2020;Yao et al, 2020;Yu et al, 2020). For instance, Abdi recorded 96% photodegradation of methyl orange within 150 min with Fe-La-doped SrTiO 3 nanoparticle as compared to 5% from bare SrTiO 3 (Abdi et al, 2020).…”