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Methane has a rather relevant role in the "Power-to-Gas" concept, which is central in the current paradigm of climate change and renewable energies. Methane, the main component of natural gas, can be produced by catalytic hydrogenation reactions, particularly of CO2. A very effective catalyst in this reaction, hydrotalcite-derived nickel nanoparticles supported on alumina, Ni/Al2O3-HTC, can be employed in a high-pressure flow reactor to convert CO2 and H2 into CH4 at 100% selectivity and 84% conversion, whereas at atmospheric pressure, methane can be obtained with up to 90% selectivity. The high-pressure aspect also allows fast-paced production—over 5 m3·h−1·kgcat−1 of CH4 can be generated. [ABSTRACT FROM AUTHOR]

The conversion of CO2 into CO is an important step in CO2 utilization to achieve clean fuels and value‐added chemicals. Herein, we explored the pyrolysis of zeolitic imidazolate framework‐8 (ZIF‐8) loaded with different amounts of Ni2+ to obtain Ni−Zn carbide (Ni3ZnC) embedded in N‐doped carbon. Ni is present in the intermetallic compound, while Zn excess remains on the N‐doped carbon. The Ni3ZnC phase catalyzes the selective hydrogenation of CO2 into CO via the reverse water gas shift reaction, reaching 100 % CO selectivity at ∼30 % CO2 conversion at 450 °C and atmosphere pressure (CO2 : H2=1 : 4, GHSV=30000 mL gcat−1 h−1). The methanation reaction of CO2/CO, which is usually favored over Ni catalysts, is suppressed. The selectivity to CO at the expense of CH4 is related to the stability of chemisorbed CO in the Ni3ZnC surface, which is lower compared to Ni surfaces. The Ni3ZnC@NC catalyst is selective towards CO over a wide range of conditions, including high pressure, that is usually required for the conversion of CO to hydrocarbons and alcohols via the Fisher‐Tropsch synthesis (FTS) process. Contrarily, a classical Ni/SiO2 catalyst prepared by impregnation produces CH4 under high pressure. [ABSTRACT FROM AUTHOR]