A series of highly active and selective CuCeOx catalysts was prepared via appropriate tuning of the parameters (concentration, temperature) of a citrates‐hydrothermal method. The obtained catalysts were characterized by various physicochemical techniques such as (in‐situ) X‐ray diffraction (XRD), N2 adsorption‐desorption, Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), while preferential oxidation of CO (CO‐PROX) in H2‐rich stream was used as probe reaction. Suitable modification of the hydrothermal parameters resulted in catalysts with remarkable performance in CO‐PROX reaction, which was strongly dependent on the concentration of oxygen vacancies and reduced copper species. [ABSTRACT FROM AUTHOR]