CO2 hydrogenation to methane over mesoporous Co/SiO2 catalysts: Effect of structure. (July 2018)

• Record Type: Journal Article
• Authors: Zhou, Guilin; Liu, Huiran; Xing, Yingzhi; Xu, Shiyu; Xie, Hongmei; Xiong, Kun
• Is Part Of: Journal of CO₂ utilization. Volume 26(2018)
• Page Start: 221
• Page End: 229
• Publication Date: 2018-07
• Subjects: Mesoporous Co/SiO2 catalysts -- Structure -- Carbon dioxide -- Catalytic hydrogenation -- Methanation; Carbon dioxide -- Periodicals; Carbon dioxide -- Environmental aspects -- Periodicals; Carbon dioxide mitigation -- Periodicals; Carbon dioxide; Carbon dioxide -- Environmental aspects; Carbon dioxide mitigation; Periodicals; 628.53205
• DOI: 10.1016/j.jcou.2018.04.023
• Languages: English
• ISSNs: 2212-9820

Abstract

Graphical abstract: The CO2 molecules can be effectively hydrogenated to CH4 molecules on the prepared mesoporous Co/SiO2 catalyst, and the performances of the Co/SiO2 catalysts can be obviously affected by the structure tuned by changing the crystallization temperature of preparing SiO2 support. With the increasing crystallization temperature (40–140 °C), the pore size and specific surface area of the prepared mesoporous Co/SiO2 catalysts increase. While the CO2 reaction rate and CH4 selectivity increase to the maximums over the mesoporous Co/SiO2 catalyst when the SiO2 support is prepared at 100 °C with the pore size of 6.0 nm and specific surface area of 387 m 2 /g, and then decrease. Highlights: Mesoporous Co/SiO2 catalysts with different pore structures were prepared. Highly active and stable catalyst were prepared by grind-impregnation method. The structure of the Co/SiO2 catalysts depends on the crystallization temperature of preparing SiO2 . The dispersity of metal Co species is related to the structure of the Co/SiO2 catalysts. CO2 methanation performances obviously depend on the structure of the mesoporous Co/SiO2 catalyst. Abstract: The mesoporous Co/SiO2 catalysts with 10 wt.% Co loading were prepared by grind-impregnation method for CO2 hydrogenation, and the mesoporous SiO2 materials with different structures were used as the supports. The physicochemical properties of the Co/SiO2 catalysts were characterized by TEM, BET, H2 -TPR, XRD, and CO2 -TPD. The results indicate that the pore size, specific surface area, and the Co° species crystallinity of the Co/SiO2 catalyst increase with increasing crystallization temperature of preparing SiO2 support. The Co/SiO2 catalyst has the best CO2 adsorption property when SiO2 support is prepared at the crystallization temperature of 100 °C. The CO2 reaction rate (CO2 conversion) of the Co/SiO2 catalysts is as follows: CK100 > CK080 > CK120 > CK060 > CK140 > CK040, and the CH4 selectivity follows the order: CK100 > CK080 > CK120 > CK140 > CK060 > CK040, accompanied by a certain amount of by-product CO molecules. At 360 °C, the CO2 reaction rate (CO2 conversion) of the CK100 catalyst is up to 3.29 × 10 −5 mol/gcat /s (44.3%), the CH4 and CO selectivity are 86.5% and 13.5%, respectively.