TY - JOUR
T1 - Remarkable enhancement of pyrolytic carbon deposition on ordered mesoporous silicas by their trimethylsilylation
AU - Hoshikawa, Yasuto
AU - Castro-Muñiz, Alberto
AU - Komiyama, Hiroshi
AU - Ishii, Takafumi
AU - Yokoyama, Takuji
AU - Nanbu, Hironobu
AU - Kyotani, Takashi
N1 - Funding Information:
This research was partially supported from Grant-in-Aid for young scientists (B) 24760541, by the Ministry of Education, Science, Sports and Culture, Japan and A. Castro-Muñiz acknowledges support from the Principado de Asturias government for a “Clarín” postdoctoral contract.
PY - 2014
Y1 - 2014
N2 - We propose a novel and simple method to uniformly deposit a thin carbon layer on the pore walls in mesoporous silica (MPS) by the chemical vapor deposition (CVD) at as low a temperature as 600 °C. Four types of MPSs (FSM16, SBA15, TMPS16 and MCM41) were trimethylsilylated and then the silylated MPSs were subjected to the CVD using acetylene. Thanks to the silylation, pyrolytic carbon deposition was significantly enhanced, although only little carbon deposition occurred on the non-silylated MPSs. It is found from the analyses of the former three types of MPSs that the carbon was deposited solely on the mesopore surface as a very thin layer and thereby the carbon-coated MPSs still keep a high surface area and a large pore volume with their mesopore structures intact. The decomposition of the trimethylsilyl groups during the CVD resulted in the formation of Si radicals on the silica surface and their catalysis can explain the observed uniform carbon coating, i.e., the radicals catalyze the trimerization of acetylene to form benzene and induce the carbonization on the silica surface. This mechanism allows the carbonization to occur only on the silica surface and the uniform carbon deposition was achieved as a result.
AB - We propose a novel and simple method to uniformly deposit a thin carbon layer on the pore walls in mesoporous silica (MPS) by the chemical vapor deposition (CVD) at as low a temperature as 600 °C. Four types of MPSs (FSM16, SBA15, TMPS16 and MCM41) were trimethylsilylated and then the silylated MPSs were subjected to the CVD using acetylene. Thanks to the silylation, pyrolytic carbon deposition was significantly enhanced, although only little carbon deposition occurred on the non-silylated MPSs. It is found from the analyses of the former three types of MPSs that the carbon was deposited solely on the mesopore surface as a very thin layer and thereby the carbon-coated MPSs still keep a high surface area and a large pore volume with their mesopore structures intact. The decomposition of the trimethylsilyl groups during the CVD resulted in the formation of Si radicals on the silica surface and their catalysis can explain the observed uniform carbon coating, i.e., the radicals catalyze the trimerization of acetylene to form benzene and induce the carbonization on the silica surface. This mechanism allows the carbonization to occur only on the silica surface and the uniform carbon deposition was achieved as a result.
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U2 - 10.1016/j.carbon.2013.09.075
DO - 10.1016/j.carbon.2013.09.075
M3 - Article
AN - SCOPUS:84892814562
VL - 67
SP - 156
EP - 167
JO - Carbon
JF - Carbon
SN - 0008-6223
ER -