Phase Transformation of Zr-Modified LaNiO₃ Perovskite Materials: Effect of CO₂ Reforming of Methane to Syngas

Zr-modified LaNiO3 catalysts (LaNixZr1-xO3; 0 <= x <= 1) are synthesized by the sol-gel method. The physio-chemical properties of materials are investigated using different characterization techniques and evaluated for the CO2 reforming of methane to syngas. Interestingly, the characterization studies revealed the phase transformation from La-Zr pyrochlore to La-Ni perovskite depending on the Ni:Zr ratio in the material. The formation of the pyrochlore phase is observed for high-Zr-containing catalysts, thus leading to the production of bulk NiO. The formation of La-Ni perovskite is observed for high-Ni-containing catalysts and the ZrO2 acted as a support. The formation of La-Ni perovskite supported on ZrO2 enhanced the Ni dispersion of the catalysts. The high dispersion of Ni enhanced the catalytic activity, and LaNi0.8Zr0.2O3 showed the best performance among all of the studied catalysts in terms of conversions and the H-2/CO ratio.