Nanostructured co-precipitated Ce0.9Ln0.1O2 (Ln = La, Pr, Sm, Nd, Gd, Tb, Dy, or Er) for thermochemical conversion of CO2

Abstract

The influence of lanthanide metal cations doped into the CeO2 crystal structure (to form Ce0.9Ln0.1O2; Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, or Er) on thermochemical reduction and the CO2 splitting ability of Ce0.9Ln0.1O2 is scrutinized using thermogravimetric analysis. Ce0.9Ln0.1O2 redox materials are effectively synthesized by co-precipitation of hydroxides. As-synthesized Ce0.9Ln0.1O2 redox materials are further characterized based on their phase composition, crystallite size, surface area, and morphology using powder X-ray diffraction, Brunauer-Emmett-Teller surface area analysis, and scanning electron microscopy. The thermal reduction and CO2 splitting aptitude of Ce0.9Ln0.1O2 redox materials are examined by performing 10 consecutive thermochemical cycles. The results imply that insertion of Sm3+, Er3+, Tb3+, Dy3+, and La+3 in place of Ce4+ in the fluorite crystal structure of CeO2 (forming Ce0.9Ln0.1O2) enhances the O2 liberation by 22.5, 14.6, 12.6, 5.85, and 2.96 ?mol O2/g?cycle, respectively. Besides, CeLa is observed to be more active towards the CO2 splitting reaction than CeO2 and the other Ce0.9Ln0.1O2 redox materials investigated in this study.