Increase in stability of BaCo/CeO₂ catalyst by optimizing the loading amount of Ba promoter for high-temperature water-gas shift reaction using waste-derived synthesis gas

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, H₂–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 (Co⁰). 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.