Ni/CexZr1-xO2 catalyst prepared via one-step co-precipitation for CO2 reforming of CH4 to produce syngas: role of oxygen storage capacity (OSC) and oxygen vacancy formation energy (OVFE)

Ceria-zirconia solid solution (Ce 0.5 Zr 0.5 O 2 )-supported Ni catalyst (15 wt. %) is prepared by one-step co-precipitation followed by calcination reduction for CO 2 reforming of CH 4 (DRM). Oxygen storage capacity (OSC) is measured by O 2 pulse injection at the reaction temperature. The solid solution is formed upon incorporating Zr 4+ into ceria, subsequently accelerating oxygen mobility from lattice (bulk) to the surface, enhancing %Ce 3+ due to increased oxygen vacancies, and thus improving OSC, reducibility, surface basicity, and Ni dispersion compared to pure CeO 2 and ZrO 2 . The solid solution exhibits better conversions of CH 4 and CO 2 , a higher H 2 /CO ratio, and low carbon deposition compared to its pure counterpart. The density functional theory (DFT) studies unveil oxygen vacancy formation energy (OVFE) as a descriptor that decreased for Ce 0.5 Zr 0. 5 O 2 due to the incorporation of Zr 4+ and enhanced mobility of O anions, OSC, and reducibility.