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.