LAUSR

Strong metal–support interactions can significantly influence catalytic performance. On titania supports, these interactions often involve the formation of a substoichiometric TiOX overlayer during high‐temperature reduction, which can be reversed by treatments under dioxygen. Under CO2 hydrogenation conditions, where water is produced, complete removal of the TiOX overlayer has been reported, raising questions about its stability in the presence of a mild oxidant such as CO2. In this study, in situ and operando techniques were employed to examine the effect of varying conditions on both the titania overlayer and cobalt species in a Co/TiO2 catalyst. After reduction at 350 °C, the overlayer consisted of stoichiometric anatase TiO2, while cobalt remained partially reduced. Exposure to CO2/H2 at 220 °C enabled complete cobalt reduction without affecting the TiO2 overlayer. In contrast, pure CO2 at 220 °C caused overlayer removal and full cobalt oxidation. The impact of this CO2‐mediated reversibility on CO2 hydrogenation was also evaluated. Although steady‐state activity was largely unaffected, the transient regime showed substantial changes in selectivity and behavior. These results demonstrate that different treatments can strongly influence both the stability and reactivity of Co/TiO2 catalysts, highlighting the importance of dynamic SMSI effects in CO2 hydrogenation.