TY - JOUR
T1 - Characterization of mesoporous VO x /MCM-41 composite materials obtained via post-synthesis impregnation
AU - Bukallah, Saeed B.
AU - Bumajdad, Ali
AU - Khalil, Kamal M.S.
AU - Zaki, Mohamed I.
N1 - Funding Information:
We would like to acknowledge the grants ( 14-03-2-11/08 and 04-03-2-11/04 , made for one of us (S.B.B.)) from the Research Affairs at the UAE University for financial support and analytical facilities at the CLU. Moreover, we appreciate the excellent technical assistance found at the analytical units of SAF (GS01/01) of Kuwait University.
PY - 2010/8/15
Y1 - 2010/8/15
N2 - Spherical-particle MCM-41 was synthesized at room temperature, and, then, impregnated with aqueous solutions of NH 4 VO 3 to produce variously loaded VO x /MCM-41 composite materials. Bulk and surface properties of the materials thus produced were characterized by means of X-ray powder diffractometry (XRD), infrared spectroscopy (FTIR), N 2 sorptiometry and X-ray photoelectron spectroscopy (XPS). Results obtained indicated that subsequent calcination at 550 °C (for 2 h) of the blank and impregnated MCM-41 particles, results in materials assuming the same bulk structure of MCM-41, and exposing uniformly mesporous, high area surfaces (P w = 2.0-2.3 nm; 974-829 m 2 /g), except for the material obtained at 20 wt%-V 2 O 5 that was shown to suffer a considerable loss on surface area (down to 503 m 2 /g). XPS results implied that the immobilization of the VO x species occurs via interaction with surface OH/H 2 O groups of MCM-41, leading to the formation of vanadate (VO 3 - ) surface species, as well as minor V-O-Si and V 2 O 5 -like species. However, in all cases, the vanadium sites remained pentavalent and exposed on the surface.
AB - Spherical-particle MCM-41 was synthesized at room temperature, and, then, impregnated with aqueous solutions of NH 4 VO 3 to produce variously loaded VO x /MCM-41 composite materials. Bulk and surface properties of the materials thus produced were characterized by means of X-ray powder diffractometry (XRD), infrared spectroscopy (FTIR), N 2 sorptiometry and X-ray photoelectron spectroscopy (XPS). Results obtained indicated that subsequent calcination at 550 °C (for 2 h) of the blank and impregnated MCM-41 particles, results in materials assuming the same bulk structure of MCM-41, and exposing uniformly mesporous, high area surfaces (P w = 2.0-2.3 nm; 974-829 m 2 /g), except for the material obtained at 20 wt%-V 2 O 5 that was shown to suffer a considerable loss on surface area (down to 503 m 2 /g). XPS results implied that the immobilization of the VO x species occurs via interaction with surface OH/H 2 O groups of MCM-41, leading to the formation of vanadate (VO 3 - ) surface species, as well as minor V-O-Si and V 2 O 5 -like species. However, in all cases, the vanadium sites remained pentavalent and exposed on the surface.
KW - MCM-41
KW - Mesoporous
KW - VO /MCM-41 composites
KW - X-ray diffractometry
KW - X-ray photelectron spectroscopy
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U2 - 10.1016/j.apsusc.2010.03.137
DO - 10.1016/j.apsusc.2010.03.137
M3 - Article
AN - SCOPUS:77953130220
SN - 0169-4332
VL - 256
SP - 6179
EP - 6185
JO - Applied Surface Science
JF - Applied Surface Science
IS - 21
ER -