Evaluation of redox performance of silver and transition metal-doped ternary ceria oxides for thermochemical splitting of CO2

Abstract

Synthesis of Ce0.9M0.05Ag0.05O2‐δ materials (where, M = Ni, Zn, Mn, Fe, Cu, Cr, Co, Zr) via coprecipitation of hydroxide method and examination of these materials toward multiple thermochemical CO2 splitting (CS) cycles is reported in this paper. Physical properties of the derived Ce0.9M0.05Ag0.05O2‐δ materials were estimated by analyzing the calcined powder using a powder X‐ray diffractometer (PXRD) and scanning electron microscope (SEM). The redox reactivity (RR) of each Ce0.9M0.05Ag0.05O2‐δ material was also evaluated by conducting high‐temperature thermogravimetric experiments. The inclusion of Ag as an active dopant has improved the RR of all the Ce0.9M0.05Ag0.05O2‐δ materials as compared with the Ce0.9M0.1O2‐δ materials. Among all the Ce0.9M0.05Ag0.05O2‐δ materials, Zn5Ag5Ce material was capable of releasing highest amount of O2 84.1 μmol O2/g·cycle and the Cr5Ag5Ce material indicated maximum CO production (151.6 μmol CO/g·cycle). The uppermost CO/O2 molar ratio equal to 1.89 was observed in case of Cr5Ag5Ce material. The quantity of O2 released and CO produced by Cr5Ag5Ce material was superior as compared with CeO21 by 30.7 μmol O2/g·cycle and 62.8 μmol CO/g·cycle, respectively.