The NixCe0.75Zr0.25−xO2 solid solution and the RWGS

• RWGS catalysts based on Ni, Ce and Zr are very active, stable and selective to CO.
• The sites on the Ni-mixed oxides interface are very active.
• Ni is incorporated into the Ce0.75Zr0.25O2 lattice by co-precipitation or impregnation.
• The higher the reducibility of the mixed oxides the higher the activity in the RWGS.

Catalysts based on Ni, Ce and Zr, were prepared using different procedures. The performance of these solids was evaluated in the RWGS reaction. Raman spectroscopy, N2 physisorption, dehydrogenation of cyclohexane reaction, temperature programmed reduction, temperature programmed desorption of CO2 and temperature programmed surface reaction were employed to characterize these catalysts. It was shown that Ni is able to be incorporated into the Ce0.75Zr0.25O2 lattice by co-precipitation or by impregnation generating active RWGS catalysts. It was inferred that the higher the reducibility of the oxides based on Ce, Zr and Ni, the higher the activity in the RWGS reaction. The mixed oxides composed of Ce, Zr and Ni are also very promising components of catalytic systems employed in reactions where the RWGS is one of the steps, as for instance, processes which generate hydrocarbons from CO2. Catalysts based on Ni supported on NiCeZr are very active, stable and selective to CO at high temperatures. Two different sites can be considered for this reaction: one on the mixed oxide and the other on the interface between Ni and the oxide, being the latter the most active.

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