Evaluation of MgO as a promoter for the hydrogenation of CO2 to long-chain hydrocarbons over Fe-based catalysts

• Published in: Applied catalysis. B, Environmental Vol. 338; p. 123052
• Main Authors: Ahmed, Sheraz, Irshad, Muhammad, Yoon, Wonjoong, Karanwal, Neha, Sugiarto, Junjung Rohmat, Khan, Muhammad Kashif, Kim, Soek Ki, Kim, Jaehoon
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.12.2023
• Subjects: CO2 hydrogenation; Deactivation; Fe catalyst; Fischer–Tropsch synthesis; Mg promotor; Mg promotor; Deactivation; CO2 hydrogenation; Fe catalyst; Fischer–Tropsch synthesis
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2023.123052

Thermocatalytic conversion of CO2 into liquid fuels and chemicals is a promising approach to mitigate global warming. Although, the CO2 conversion and long-chain hydrocarbon selectivity are highly dependent on the choice of metal-oxide promoter, but role of the promoter remains unclear. Herein, the role of MgO as a promoter for an Fe-based catalyst was investigated. Bimetallic Na-FeMgOx catalyst exhibited a high C5+ yield of 25.1% with a CO2 conversion of 49.1% at the early stage of the reaction. The presence of MgO facilitates the reduction of Fe oxides and formation of oxygen vacancies by transferring electrons to Fe-based phases. In addition, at the early stage of reaction, the decoration of the Mg oxide surface with nanosized χ-Fe5C2 enhances the C5+ yield. However, the progressive transformation of MgO to MgCO3 during CO2 conversion deactivates the Na-FeMgOx catalyst. A detailed deactivation mechanism is also discussed. [Display omitted] •MgO-promoted Fe3O4 produced a C5+ yield of 25.1% at a CO2 conversion of 49.1%.•MgO performed its role as an electronic promoter on Fe3O4 and Fe5C2.•The formation of MgCO3 suppressed the promotional effect of MgO.•Re-oxidation of Fe5C2 to Fe3O4 during CO2 conversion was main deactivation mechanism.