Au/CeO2 nanorods modified by TiO2 through a combining dealloying and calcining method for low-temperature CO oxidation

Abstract TiO2/Au/CeO2 catalysts with different TiO2 contents were successfully synthesized through combining a dealloying Al-Ce-Ti-Au precursor alloy and calcining in O2. XRD, SEM, HRTEM, TEM-EDX mapping, N2 adsorption-desorption, H2-TPR, O2-TPD, Raman spectroscopy, XPS, and in situ DRIFTS were used to characterize the structural phases, microstructures, and physicochemical properties of the samples. The results revealed that the TiO2/Au/CeO2 catalysts prepared from Al89.7Ce9.5Ti0.5Au0.3 had a structure in which Au and TiO2 nanoparticles were loaded onto the surfaces of CeO2 nanorods in a porous framework, resulting in a large specific surface area and a small pore size. The results of an experimental test of the catalytic oxidation of CO indicated that the TiO2/Au/CeO2 catalysts prepared from Al89.7Ce9.5Ti0.5Au0.3 showed the highest activity for CO oxidation. The temperature required for 50% CO conversion was as low as 5 °C and 98% CO conversion was achieved at 40 °C. The catalysts were stable even after 100 h of catalytic oxidation. The introduction of a small amount of TiO2 into the Au/CeO2 is thought to have created an increased number of oxygen vacancies and an increased concentration of Auδ+ species. This leads to stronger interactions between the Au and CeO2 and more active oxygen species at the surface, which enhances the catalytic activity. The present work further develops catalytic materials with high performance and low cost.