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

[Display omitted] ► The Pt/TiO2 catalyst shows a high level of activity in the RWGS reaction. ► Catalytic activity was dependent on Pt dispersion and support's reducibility. ► The RWGS reaction was in agreement with the surface redox mechanism. 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 H2 TPR and FT-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.