Direct non-oxidative methane coupling on vitreous silica supported iron catalysts

• Published in: Catalysis today 2023-04, Vol.416, p.113873, Article 113873
• Main Authors: Liu, Zixiao, Cheng, Sichao, Schulman, Emily, Chen, Weiqi, Vlachos, Dionisios G., Shu, Yuying, Tran, Dat T., Liu, Dongxia
• Format: Article
• Language: English
• Subjects: Cristobalite; Flame fusion; Natural gas; Non-oxidative methane coupling; Vitreous silica
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2022.08.015

Direct non-oxidative methane coupling (NMC) is one of the promising pathways for methane upgrading into value-added olefin and aromatic hydrocarbons. The silica-supported iron (i.e., Fe/SiO2) catalyst has been reported effective for NMC, but the effects of silica support on the catalyst property and NMC performance have rarely been explored. In this work, we prepared a vitreous silica-supported iron (Fe/SiO2-V) catalyst by flame fusion of a mixture of quartz silica and fayalite. The physicochemical properties and NMC performance of the as-prepared catalysts were measured. Compared to crystalline cristobalite support in Fe/SiO2 catalyst that has been studied previously, vitreous silica support has disordered Si-O bonds and structural defects, enabling better iron dispersion and more vital metal-support interaction. The as-prepared Fe/SiO2-V catalyst had a shorter induction period in methane activation and lower coke yield in NMC. The increase in iron concentration in Fe/SiO2-V catalysts elongated the catalyst induction period and promoted aromatics and coke formation. The coke type of the spent Fe/SiO2-V catalyst is more uniform than the cristobalite-supported iron catalyst. [Display omitted] •Vitreous silica-supported iron catalysts were prepared by an oxyhydrogen flame fusion method.•The amorphous vitreous silica support contains disordered and defective Si-O bonds.•Iron has higher dispersion and more uniform bonding in the vitreous silica support.•Vitreous silica-supported iron enabled fast methane activation and low coking in NMC.•Increase in iron loading in vitreous silica support promoted aromatics formation.