Preparation of oxygen vacancy-controllable CeO2 by electrotransformation of a CeCl3 solution and its oxidation mechanism. Issue 5 (1st April 2020) - Liu, Jiang
Abstract: CeO2 was successfully prepared by electrotransformation of CeCl3 solution in previous work. In this work, the oxidation mechanism of Ce 3+ was determined by cyclic voltammetry and a potential-pH diagram, which indicated that Ce 3+ was oxidized by oxygen during the electrotransformation, and the important role of the oxygen content in solution was confirmed. Thus, the influence of atmosphere (air/argon/oxygen) on CeO2 preparation was investigated by adjusting the gas type and flow rate. XRD patterns demonstrated the cubic fluorite structure and grain size of CeO2 . With an increase in the gas flow rate, the grain size decreased, but the particle size increased. This result indicated that the smaller grains contained more lattice defects and higher surface energy, so the grains preferred to agglomerate together, forming larger particles. XPS spectra proved that Ce 3+ and Ce 4+ both existed in the CeO2 samples. Raman scattering revealed that more oxygen vacancies could be produced with an argon atmosphere and high gas flow.