TY - JOUR
T1 - Concentration of surface hydroxyl groups on MCM-41
AU - Jentys, A.
AU - Kleestorfer, K.
AU - Vinek, H.
N1 - Funding Information:
This work was supported by the “Fonds zur Förderung der Wissenschaftlichen Forschung” under project P10874 CHE and by the “Jubiläumsstiftung der Österreichischen Nationalbank”.
PY - 1999/2
Y1 - 1999/2
N2 - The type and concentration of hydroxyl groups present on MCM-41 were investigated by infrared spectroscopy as a function of the Si/Al ratio and the pore size. The purely siliceous samples contained the highest concentrations of weakly acidic silanol groups. On aluminum-containing MCM-41 samples additionally Brønsted and strong Lewis acid sites were observed. Their concentration increased with increasing aluminum content, while that of the weakly acidic silanol groups decreased. For MCM-41 samples prepared with C12TMABr, higher concentrations of weakly acidic hydroxyl groups and strong Lewis acid sites, and lower concentrations of Brønsted acid sites, were observed compared with MCM-41 prepared with C16TMABr. Comparison of the spectroscopic data with the results of a structure simulation revealed that the internal surface of MCM-41 is only partially covered with hydroxyl groups.
AB - The type and concentration of hydroxyl groups present on MCM-41 were investigated by infrared spectroscopy as a function of the Si/Al ratio and the pore size. The purely siliceous samples contained the highest concentrations of weakly acidic silanol groups. On aluminum-containing MCM-41 samples additionally Brønsted and strong Lewis acid sites were observed. Their concentration increased with increasing aluminum content, while that of the weakly acidic silanol groups decreased. For MCM-41 samples prepared with C12TMABr, higher concentrations of weakly acidic hydroxyl groups and strong Lewis acid sites, and lower concentrations of Brønsted acid sites, were observed compared with MCM-41 prepared with C16TMABr. Comparison of the spectroscopic data with the results of a structure simulation revealed that the internal surface of MCM-41 is only partially covered with hydroxyl groups.
KW - Infrared spectroscopy
KW - MCM-41
KW - Structure simulation
KW - Surface hydroxyl groups
UR - http://www.scopus.com/inward/record.url?scp=0032652422&partnerID=8YFLogxK
U2 - 10.1016/S1387-1811(98)00265-0
DO - 10.1016/S1387-1811(98)00265-0
M3 - Article
AN - SCOPUS:0032652422
SN - 1387-1811
VL - 27
SP - 321
EP - 328
JO - Microporous and Mesoporous Materials
JF - Microporous and Mesoporous Materials
IS - 2-3
ER -