The loading amount of Ba promoter in the 15 wt% Co/CeO2 catalyst system was varied from 0 wt% to 3 wt %, and the resulting catalysts were used for the high-temperature water-gas shift (HTS) reaction. The catalysts were prepared by the incipient wetness co-impregnation method and studied through various characterization techniques such as X-ray diffraction, Brunauer-Emmet-Teller measurements, CO-chemisorption, H-2-temperature programmed reduction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The doping of Ba as a promoter in the optimal amount (1-2 wt%) improves the reducibility of the catalyst and enhances its sintering resistance. However, the doping of an excessive amount (>= 3 wt%) of the promoter lowers the reducibility of the catalyst, resulting in the instability of the active phase (Co-0). Overall, the 1% BaCo/CeO2 catalyst exhibited the best performance even at a severe reaction condition (CO conc. = 38%, GHSV = 143,000 h(-1)) owing to the strong resistance to the sintering and high stability of the active phase. (c) 2019 Elsevier Ltd. All rights reserved.