The decomposition of La2NiO4+delta (LNO) was studied in presence of a second phase, Sm0.2Ce0.8O2 (-) (delta) (SDC), for volume fractions of LNO below 55 vol%, after sintering at 1300 degrees C for 5 h. The details of the decomposition reaction were studied using a combination of experimental methods including X-ray diffractometry, dilatometry analysis and scanning electron microscopy imaging. The La2O3 resulting from the LNO decomposition gets incorporated into SDC phase leading to doubly doped ceria and the formation of free NiO. (C) 2016 Elsevier B.V. All rights reserved.