Tuning Ru/Ni sites in the perovskite-based precursor synthesis to make more efficient and durable dual-function materials for integrated CO2 capture and methanation

A new generation of Dual Function Materials (DFMs) were obtained after the controlled reduction of 20 % La 0.6 Ca 0.4 Ni 0.95 Ru 0.05 O 3 /CeO 2 synthesized combining citric acid-wetness impregnation methods. Different parameters such as pH of the starting solution, calcination protocol were modified in order to synthesize materials with variable nanostructure, surface chemistry and textural properties, thereby effectively tuning the material activity and stability for the integrated CO 2 adsorption and in situ methanation operation. The samples were extensively characterized before and after catalytic tests by XRD, Raman, STEM-EDS, XPS, N 2 adsorption-desorption, H 2 -TPR, H 2 -TPD, CO 2 -TPD, and H 2 -TPSR. It was found that the DFM obtained from the precursor prepared in absence of NH 3 promoted Ru accommodation within the perovskite structure. The corresponding DFM showed enhanced textural properties, Ru/Ni actives sites accessibility and weak/medium basic sites concentration and, consequently, displayed the highest CH 4 yield (312 µmol g −1 ) and fastest CH 4 production kinetics under cycles of CO 2 adsorption and in situ hydrogenation to CH 4 . Furthermore, this sample showed higher stability than conventional Ru-based DFMs, with CH 4 production decreasing by less than 6 % compared to 25 % observed for conventional ones, due to a lower tendency for metal sintering, emerging as a promising alternative for long-term operation under realistic industrial conditions. • A new generation of Ru-doped DFMs is synthesized by optimizing 20 % La 0.6 Ca 0.4 Ni 0.95 Ru 0.05 O 3 /CeO 2 synthesis. • The absence of NH 3 in the synthesis maximizes Ru insertion within the perovskite. • Enhanced CH 4 production (312 µmol g −1 ) at low/intermediate temperature. • Enhanced stability, with CH₄ yield degradation under 6 % after long-term cycling. • Potential for industrial CO 2 adsorption and in situ methanation applications.