Effect of Ce/Zr Composition on Structure and Properties of Ce 1-x Zr x O 2 Oxides and Related Ni/Ce 1-x Zr x O 2 Catalysts for CO 2 Methanation.

Ce 1-x Zr x O 2 oxides (x = 0.1, 0.25, 0.5) prepared via the Pechini route were investigated using XRD analysis, N 2 physisorption, TEM, and TPR in combination with density functional theory calculations. The Ni/Ce 1-x Zr x O 2 catalysts were characterized via XRD analysis, SEM-EDX, TEM-EDX, and CO chemisorption and tested in carbon dioxide methanation. The obtained Ce 1-x Zr x O 2 materials were single-phase solid solutions. The increase in Zr content intensified crystal structure strains and favored the reducibility of the Ce 1-x Zr x O 2 oxides but strongly affected their microstructure. The catalytic activity of the Ni/Ce 1-x Zr x O 2 catalysts was found to depend on the composition of the Ce 1-x Zr x O 2 supports. The detected negative effect of Zr content on the catalytic activity was attributed to the decrease in the dispersion of the Ni 0 nanoparticles and the length of metal-support contacts due to the worsening microstructure of Ce 1-x Zr x O 2 oxides. The improvement of the redox properties of the Ce 1-x Zr x O 2 oxide supports through cation modification can be negated by changes in their microstructure and textural characteristics.