Journal
JOURNAL OF POROUS MATERIALS
Volume 23, Issue 2, Pages 475-487Publisher
SPRINGER
DOI: 10.1007/s10934-015-0101-z
Keywords
Silica-doped alumina; Thermally stable; Large pore size; High surface area
Funding
- U.S. Department of Energy [DE-FG02-05ER15666]
- National Science Foundation [CHE-0959862]
- U.S. Department of Energy's National Nuclear Security Administration [DE-AC04-94AL85000]
Ask authors/readers for more resources
A facile, solvent-deficient, one-pot synthesis of a thermally stable silica-doped alumina, having high surface area, large pore volume and uniquely large pores, has been developed. Silica-doped alumina (SDA) was synthesized by adding 5 wt% silica from tetraethyl orthosilicate (TEOS) to aluminum isoproxide (AIP), a 1:5 mol ratio AIP to water, and a 1:2 mol ratio TEOS to water in the absence of a template. The structure of silica-doped alumina was studied by in situ high-temperature powder XRD, nitrogen adsorption, thermogravimetric analysis, solid-state NMR, and TEM. The addition of silica significantly increases the stability of gamma-Al2O3 phase to 1200 A degrees C while maintaining a high surface area, a large pore volume and a large pore diameter. After calcination at 1100 A degrees C for 2 h, a surface area of 160 m(2)/g, pore volume of 0.99 cm(3)/g, and a bimodal pore size distribution of 23 and 52 nm are observed. Compared to a commercial silica-doped alumina, after calcination for 24 h at 1100 A degrees C, the surface area, pore volume, and pore diameter SDA are higher by 46, 155, and 94 %, respectively. Results reveal that Si stabilizes the porous structure of gamma-Al2O3 up to 1200 A degrees C, while unstabilized alumina is stable to only 900 A degrees C. From our data, we infer that Si enters tetrahedral vacancies in the defect spinel structure of alumina without moving Al from tetrahedral positions and forms a silica-alumina interface.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available