Improving Low‐Temperature CO<sub>2</sub> Methanation by Promoting Ni‐Al LDH‐Derived Catalysts with Alkali Metals
Yan Resing Dias, Fabiano Bernardi, Oscar W. Perez‐Lopez
Abstract
Abstract Fossil fuel depletion and environmental impacts caused by greenhouse gas emissions such as CO 2 are significant issues securing nature preservation within a sustainable economy. CO 2 methanation is a promising process to mitigate CO 2 emissions and reuse it to produce CH 4 , serving as fuel, chemical feedstock, and energy source. A series of LDH‐derived Ni‐Al catalysts promoted by Li, Mg, Ca, and La were prepared via co‐precipitation. Characterization by N 2 physisorption, X‐ray diffraction (XRD) and photoelectron spectroscopy (XPS), as well as thermal techniques such as temperature programmed reduction (H 2 ‐TPR), desorption (CO 2 ‐TPD, H 2 ‐TPD), and oxidation (TPO) analyses were performed. Low‐temperature catalytic tests (200–400 °C) revealed that alkali metal modification improves performance even at 200 °C, where the Ni55Ca11Al33 catalyst achieved 74 % CO 2 conversion with 100 % CH 4 selectivity by enhancing basicity and metal‐support interaction, high Ni dispersion and small crystallite sizes, providing proper sites to adsorb and activate CO 2 . Moreover, the catalysts presented excellent resistance to deactivation, maintaining high stability during 10 h on stream. These results prove that Ni‐Al mixed oxides, LDH‐derived catalysts performances can be further improved by incorporating alkali metals into less energy‐spending, low‐temperature CO 2 methanation processes.