Effect of support on the catalytic performance of Au-Co3O4 catalysts: An operando DRIFTS-MS study of the propane total oxidation

Abstract

This study investigates the effect of different supports on the catalytic performance of Au-Co3O4 nanoparticles in the total oxidation of propane, aiming to understand the interaction between the supported gold and cobalt oxide particles and the role of the support in enhancing the catalytic activity. Catalysts were prepared via the sequential deposition–precipitation with urea method, with TiO2 and Al2O3 as supports. We found that the AuCo3O4/TiO2 system exhibited higher catalytic activity and lower activation energy, compared to AuCo3O4/Al2O3. The enhanced performance of the AuCo3O4/TiO2 catalyst was attributed to the high mobility of surface oxygen species and the presence of oxygen vacancies. Operando DRIFTS-MS was used to characterize the intermediate species formed during the reaction. This technique revealed the presence of different intermediate species on the catalyst surfaces, with TiO2-supported catalysts showing enolate and carbonate adsorbed species at lower temperatures, enhancing the propane oxidation efficiency. In contrast, Al2O3-supported catalysts predominantly formed acetate adsorbed species at higher temperatures, indicating a less efficient oxidation process. The results demonstrated that the choice of support significantly affects the catalytic performance of Au-Co3O4 nanoparticles, with TiO2 providing superior oxyphility due to its reducibility and ability to promote the formation of active oxygen species. The study highlights the importance of the support material in the design of effective catalysts for volatile organic compounds (VOCs) oxidation.