Structure–activity relationship of an A-site-doped LaNiO3/SiO2 catalyst

Improving the anti-carbon deposition and anti-sintering ability under the premise of maintaining high catalytic activity is the core issue of Ni-based catalysts applied in CO methanation reactions. To address this issue, a La 0.75 A 0.25 NiO 3 /SiO 2 (A = Ce, Sr, Sm, and Ca) catalyst is prepared via a citric acid complexation method. XRD results show that the substituted elements (Sr, Sm, and Ca) enter the LaNiO 3 lattice and partially replace the A-site element La. The reduced Ni 0 is beneficial to improve the medium temperature activity of the catalyst. The substitution of different elements produces different electronic effects that significantly affect the size of the Ni particles and the interaction between Ni and La 2 O 3 . The catalyst with doped Ca 2+ as the A-site substituted element demonstrates better adsorption, storage, and migration capabilities for oxygen due to the lattice distortion that easily produces oxygen vacancies. Catalysts doped with Sr, Sm, and Ca as the A-site substituted element produce La 2 O 2 CO 3 after the reactions, which plays a role in eliminating carbon deposits.