TY - JOUR
T1 - Adsorption-enhanced hydrolysis of /?-1,4-glucan on graphene-based amorphous carbon bearing so3H, COOH, and OH groups
AU - Kitano, Masaaki
AU - Yamaguchi, Daizo
AU - Suganuma, Satoshi
AU - Nakajima, Kiyotaka
AU - Kato, Hideki
AU - Hayashi, Shigenobu
AU - Hara, Michikazu
N1 - Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2009/5/5
Y1 - 2009/5/5
N2 - The reaction mechanism of the hydrolysis of cellulose by a carbon-based solid acid, amorphous carbon containing graphene sheets bearing SO3H, COOH, and phenolic OH groups, has been investigated in detail through the hydrolysis of water-soluble β-1,4-glucan. Whereas a range of solid strong Brønsted acid catalysts (inorganic oxides with acidic OH groups, SO 3H-bearing resins, and the carbon-based solid acid) can hydrolyze the β-1,4-glycosidic bonds in cellobiose (the shortest water-soluble β-1,4-glucan), the tested solid acids except for the carbon material, consisting of conventional solid acids, cannot function as effective catalysts for the hydrolysis of cellohexaose (a long-chain water-soluble β-1,4-glucan). However, the carbon material exhibits remarkable catalytic performance for the hydrolysis of cellohexaose: the turnover frequency (TOF) of SO3H groups in the carbon material exceeds ca. 20 times those of the conventional solid acids, reaching that of sulfuric acid, which is the most active catalyst. Experimental results revealed that inorganic oxides with acidic OH groups are not acidic enough to decompose the hydrogen and β-1,4-glycosidic bonds in cellohexaose molecules aggregated by strong hydrogen bonds as well as cellulose and that the SO3H groups of the resins that do not adsorb β-1,4-glucan are unable to attack the hydrogen and β-1,4-glycosidic bonds in cellohexaose molecules effectively. In contrast, the carbon material is capable of adsorbing β-1,4-glucan by phenolic OH or COOH groups in the carbon material, and SO3H groups bonded to the carbon therefore function as effective active sites for both decomposing the hydrogen bonds and hydrolyzing the β-1,4-glycosidic bonds in the adsorbed long-chain water-soluble β-1,4-glucan aggregate. These results suggest that the synergetic combination of high densities of the functional groups bonded to amorphous carbon causes the efficient hydrolysis of β-1,4-glucan, including cellulose, on the carbon material.
AB - The reaction mechanism of the hydrolysis of cellulose by a carbon-based solid acid, amorphous carbon containing graphene sheets bearing SO3H, COOH, and phenolic OH groups, has been investigated in detail through the hydrolysis of water-soluble β-1,4-glucan. Whereas a range of solid strong Brønsted acid catalysts (inorganic oxides with acidic OH groups, SO 3H-bearing resins, and the carbon-based solid acid) can hydrolyze the β-1,4-glycosidic bonds in cellobiose (the shortest water-soluble β-1,4-glucan), the tested solid acids except for the carbon material, consisting of conventional solid acids, cannot function as effective catalysts for the hydrolysis of cellohexaose (a long-chain water-soluble β-1,4-glucan). However, the carbon material exhibits remarkable catalytic performance for the hydrolysis of cellohexaose: the turnover frequency (TOF) of SO3H groups in the carbon material exceeds ca. 20 times those of the conventional solid acids, reaching that of sulfuric acid, which is the most active catalyst. Experimental results revealed that inorganic oxides with acidic OH groups are not acidic enough to decompose the hydrogen and β-1,4-glycosidic bonds in cellohexaose molecules aggregated by strong hydrogen bonds as well as cellulose and that the SO3H groups of the resins that do not adsorb β-1,4-glucan are unable to attack the hydrogen and β-1,4-glycosidic bonds in cellohexaose molecules effectively. In contrast, the carbon material is capable of adsorbing β-1,4-glucan by phenolic OH or COOH groups in the carbon material, and SO3H groups bonded to the carbon therefore function as effective active sites for both decomposing the hydrogen bonds and hydrolyzing the β-1,4-glycosidic bonds in the adsorbed long-chain water-soluble β-1,4-glucan aggregate. These results suggest that the synergetic combination of high densities of the functional groups bonded to amorphous carbon causes the efficient hydrolysis of β-1,4-glucan, including cellulose, on the carbon material.
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U2 - 10.1021/la8040506
DO - 10.1021/la8040506
M3 - Article
C2 - 19397353
AN - SCOPUS:66549125324
VL - 25
SP - 5068
EP - 5075
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 9
ER -