The influence of lanthanide metal cations doped into the CeO2 crystal structure (to form Ce(0.9)Ln(0.1)O(2); Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, or Er) on thermochemical reduction and the CO2 splitting ability of Ce(0.9)Ln(0.1)O(2) is scrutinized using thermogravimetric analysis. Ce(0.9)Ln(0.1)O(2) redox materials are effectively synthesized by co-precipitation of hydroxides. As-synthesized Ce(0.9)Ln(0.1)O(2) 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 Ce(0.9)Ln(0.1)O(2) redox materials are examined by performing 10 consecutive thermochemical cycles. The results imply that insertion of Sm3+, Er3+, Tb3+, Dy3+, and La3+ in place of Ce4+ in the fluorite crystal structure of CeO2 (forming Ce(0.9)Ln(0.1)O(2)) enhances the O-2 liberation by 22.5, 14.6, 12.6, 5.85, and 2.96 mu mol O-2/g.cycle, respectively. Besides, CeLa is observed to be more active towards the CO2 splitting reaction than CeO2 and the other Ce(0.9)Ln(0.1)O(2) redox materials investigated in this study.