Effect of Ce/Zr Composition on Structure and Properties of Ce1-xZrxO2 Oxides and Related Ni/Ce1-xZrxO2 Catalysts for CO2 Methanation

Ce1-xZrxO2 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/Ce1-xZrxO2 catalysts were characterized via XRD analysis, SEM-EDX, TEM-EDX, and CO chemisorption and tested in carbon dioxide methanation. The obtained Ce1-xZrxO2 materials were single-phase solid solutions. The increase in Zr content intensified crystal structure strains and favored the reducibility of the Ce1-xZrxO2 oxides but strongly affected their microstructure. The catalytic activity of the Ni/Ce1-xZrxO2 catalysts was found to depend on the composition of the Ce1-xZrxO2 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 Ce1-xZrxO2 oxides. The improvement of the redox properties of the Ce1-xZrxO2 oxide supports through cation modification can be negated by changes in their microstructure and textural characteristics.