TY - JOUR
T1 - Exfoliated nanosheets as a new strong solid acid catalyst
AU - Takagaki, Atsushi
AU - Sugisawa, Mariko
AU - Lu, Darling
AU - Kondo, Junko N.
AU - Hara, Michikazu
AU - Domen, Kazunari
AU - Hayashi, Shigenobu
PY - 2003/5/7
Y1 - 2003/5/7
N2 - Two-dimensional metal oxide sheets in HTiNbO5 and HSr2Nb3O10, cation-exchangeable layered metal oxides, were examined as solid acid catalysts. Exfoliation of HTiNbO5 and HSr2Nb3O10 in aqueous solutions formed colloidal single-crystal TiNbO5- and Sr2Nb3O10- nanosheets, which precipitated under an acidic condition to form aggregates of HTiNbO5 nanosheets and HSr2Nb3O10 nanosheets. Although esterification of acetic acid, cracking of cumene, and dehydration of 2-propanol were not catalyzed by original HTiNbO5 because of the narrow interlayer distance, which prevents the insertion of organic molecules, HTiNbO5 nanosheets functioned as a strong solid acid catalyst for the reactions. Nanosheets of HSr2Nb3O10 exhibited no or slight catalytic activity for these reactions. NH3 temperature-programmed desorption and 1H magic-angle spinning nuclear magnetic resonance spectroscopy revealed that HTiNbO5 nanosheets have strong Brønsted acid sites, whereas HSr2Nb3O10 nanosheets do not.
AB - Two-dimensional metal oxide sheets in HTiNbO5 and HSr2Nb3O10, cation-exchangeable layered metal oxides, were examined as solid acid catalysts. Exfoliation of HTiNbO5 and HSr2Nb3O10 in aqueous solutions formed colloidal single-crystal TiNbO5- and Sr2Nb3O10- nanosheets, which precipitated under an acidic condition to form aggregates of HTiNbO5 nanosheets and HSr2Nb3O10 nanosheets. Although esterification of acetic acid, cracking of cumene, and dehydration of 2-propanol were not catalyzed by original HTiNbO5 because of the narrow interlayer distance, which prevents the insertion of organic molecules, HTiNbO5 nanosheets functioned as a strong solid acid catalyst for the reactions. Nanosheets of HSr2Nb3O10 exhibited no or slight catalytic activity for these reactions. NH3 temperature-programmed desorption and 1H magic-angle spinning nuclear magnetic resonance spectroscopy revealed that HTiNbO5 nanosheets have strong Brønsted acid sites, whereas HSr2Nb3O10 nanosheets do not.
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U2 - 10.1021/ja034085q
DO - 10.1021/ja034085q
M3 - Article
C2 - 12720462
AN - SCOPUS:0037954611
VL - 125
SP - 5479
EP - 5485
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 18
ER -