Two-step thermochemical looping using modified ceria-based materials for splitting CO2

摘要

This work presents an investigation of CeO2, Ce0.5Zr0.5O2 (CZ), and La, Pr-doped CeO2-ZrO2 (LP-CZ) for thermochemical two-step splitting of CO2. The materials are synthesized by coprecipitation method and characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and H-2 temperature-programmed reduction. The cyclic CO2 splitting performance of the samples is measured using thermogravimetric analysis. The results reveal that CZ and LP-CZ show comparable splitting efficiency with the average CO productions of 272 and 288 mu mol g(-1), respectively, which are much larger than those of CeO2. CZ and LP-CZ benefit from the Zr modification on their structure (taEuro(3) phase) and numerous oxygen vacancies which apparently facilitates oxygen migration. LP-CZ exhibits more rapid recovery post-splitting compared to the other two samples, as a result of its better thermal stability and favorable "vacancy-rich" structure for oxygen exchange and migration. This has potential to be driven for further developments in various applications.