Fabrication and characterization of highly active fibrous silica-mordenite (fs@sio2-mor) cockscomb shaped catalyst for enhanced co2 methanation

Abstract

Carbon dioxide (CO2) emissions are of global concern because of climate change. CO2 methanation is one of the most prestigious technologies to convert CO2 into value-added products such as substitute natural gas. In this study, a highly active fibrous silica-mordenite (FS@SiO2-MOR) catalyst has been synthesized by a microemulsion process and characterized by XRD, TEM, FESEM, N2 adsorption analysis, FTIR-pyrrole, CO2-TPD, and ESR spectroscopy. The CO2 methanation reaction was performed, and it was found that the FS@SiO2-MOR catalyst exhibited higher CH4 selectivity (68%) and CO2 conversion (65%) due to the distinctive fibrous morphology, which provided higher surface area, basic sites, and oxygen vacancies. In addition, the synthesized FS@SiO2-MOR catalyst exhibited high thermal stability (50 h) and significantly suppressed coke deposition compared to commercial mordenite. According to in-situ FTIR observations, the carbonyls and linear CO2* were the essential intermediates species for the formation of methane during CO2 methanation via an associative mechanism.