MOF-Based Nanocatalysts for Methanation of Carbon Dioxide and Carbon Monoxide at Ambient Pressure

Nowadays, finding catalysts that can perform the hydrogenation of CO 2 and CO with high efficiency and selectivity has become a research challenge. So, in this report, two types of porous carbon nanostructures of C UiO-66 and C UiO-66-NH2 with high surface area, which both were obtained from two types of metal–organic frameworks (MOFs) of UiO-66 and UiO-66-NH 2 as precursors, were used in the CO 2 and CO hydrogenation after loading the active metal of nickel on their surface. The results of BET-N 2 and CO 2 adsorption showed higher surface area and adsorption capacity of the catalyst supports than those of their precursors. Also, the results of X-ray photoelectron spectroscopy (XPS) analysis indicated the presence of nitrogen-containing species such as pyridine in the structure of x Ni@C UiO-66-NH2 catalysts, which can act as basicity sites in sorption of CO 2 during the hydrogenation reaction, as was confirmed by results of CO 2 -temperature-programmed desorption. Among the catalyst samples with C UiO-66-NH2 and C UiO-66 supports, the 15Ni@C UiO-66-NH2 and 20Ni@C UiO-66 catalysts with conversion efficiencies of 87% and 74.5%, respectively, and a methane selectivity of 99% showed the best performance in CO 2 methanation at the temperature of 350 °C. The reason for the better performance of x Ni@C UiO-66-NH2 catalysts compared to x Ni@C UiO-66 catalysts is the presence of basic sites created by nitrogen heteroatoms in the C UiO-66-NH2 support. Also, the results of the tests of CO 2 methanation showed that catalysts based on supports with the carbon nanostructure obtained from MOFs showed a higher efficiency compared with the catalysts with the MOF supports. The 15Ni@C UiO-66-NH2 catalyst showed impressive performance in CO methanation with an efficiency of 100% and complete selectivity of methane at 275 °C. Finally, comparing the performance of 15Ni@C UiO-66-NH2 catalyst with other reported catalysts based on carbon supports or based on MOFs, showed the high potential of this catalyst in the process of CO 2 and CO methanation.