A study on the effect of support's reducibility on the reverse water-gas shift reaction over Pt catalysts

In this study, the effect of the reducibility of the support on the mechanism of the reverse water gas shift reaction over Pt/TiO2 and Pt/Al2O3 catalysts was examined using a differential and fixed bed reactor. The kinetic study showed that the reverse water gas shift reaction using the Pt/TiO2 and Pt/Al2O3 catalysts were consistent with the redox mechanism. An elementary reaction test and XPS analysis further confirmed that the reverse water gas shift reaction proceeded through the redox mechanism via oxidation and reduction at the Pt sites and reducible support sites on the catalyst surface. In the H-2 TPR and Fr-IR experiments, the Pt/TiO2 was shown to have a new active site located at the metal-support interface. Therefore, the Pt/TiO2 catalyst produced greater CO2 conversion and TOFs due to the presence of the new active site, which resulted from the strong metal-support interaction and higher reducibility of the support relative to the Pt/Al2O3 catalyst. (C) 2012 Elsevier B.V. All rights reserved.