High-temperature synthesis of highly hydrothermal stable mesoporous silica and Fe–SiO2 using ionic liquid as a template

Mesoporous silicas and Fe-SiO{sub 2} with worm-like structures have been synthesized using a room temperature ionic liquid, 1-hexadecane-3-methylimidazolium bromide, as a template at a high aging temperature (150-190 {sup o}C) with the assistance of NaF. The hydrothermal stability of mesoporous silica was effectively improved by increasing the aging temperature and adding NaF to the synthesis gel. High hydrothermally stable mesoporous silica was obtained after being aged at 190 {sup o}C in the presence of NaF, which endured the hydrothermal treatment in boiling water at least for 10 d or steam treatment at 600 {sup o}C for 6 h. The ultra hydrothermal stability could be attributed to its high degree of polymerization of silicate. Furthermore, highly hydrothermal stable mesoporous Fe-SiO{sub 2} has been synthesized, which still remained its mesostructure after being hydrothermally treated at 100 {sup o}C for 12 d or steam-treated at 600 {sup o}C for 6 h. -- Graphical abstract: Worm-like mesoporous silica and Fe-SiO{sub 2} with high hydrothermal stability have been synthesized using ionic liquid 1-hexadecane-3-methylimidazolium bromide as a template under the assistance of NaF at high temperature. Display Omitted Research highlights: {yields} Increasing aging temperature improved the hydrothermal stability of materials. {yields}Addition of NaF enhanced the polymerizationmore » degree of silicates. {yields} Mesoporous SiO{sub 2} and Fe-SiO{sub 2} obtained have remarkable hydrothermal stability.« less