Highlights: [•] Single phase solid solution Ce1−xBi x O2−δ with the composition of x =0.1–0.5 were successfully synthesized at room temperature using simple and fast Self Propagating Room Temperature procedure (SPRT). [•] Thermal stability of Ce1−xBi x O2−δ solid solutions was investigated at various temperatures up to 1400°C. [•] It was revealed that all samples with concentration of bismuth higher than 10at.% are unstable during thermal treatment. [•] Bi leaving the structure of ceria and formation of β-Bi2O3 and β′-Bi2O3 as secondary phases. [ABSTRACT FROM AUTHOR]