TY - JOUR
T1 - Rod-, flower-, and dumbbell-like MnO 2
T2 - Highly active catalysts for the combustion of toluene
AU - Shi, Fengjuan
AU - Wang, Fang
AU - Dai, Hongxing
AU - Dai, Jianxing
AU - Deng, Jiguang
AU - Liu, Yuxi
AU - Bai, Guangmei
AU - Ji, Kemeng
AU - Au, Chak Tong
N1 - Funding Information:
The work described above was supported by the NSF of Beijing Municipality (Grant No. 2102008 ), the NSF of China (Grant Nos. 20973017 and 21077007 ), the National High-Tech Research and Development (863) Program of China (Grant No. 2009AA063201), the Creative Research Foundation of Beijing University Technology (Grant Nos. 00500054R4003 and 005000543111501 ), and the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (Grant Nos. PHR201007105 and PHR201107104). CTAU thanks the Foundation of the Hong Kong Baptist University (Grant No. FRG2/09-10/023 ) for financial support. We also thank Mrs. Jianping He (State Key Laboratory of Advanced Metals and Materials, University of Science & Technology Beijing) for doing the SEM analysis.
PY - 2012/8/8
Y1 - 2012/8/8
N2 - The rod-like tetragonal α-MnO 2, flower-like hexagonal ε-MnO 2, and dumbbell-like tetragonal β-MnO 2 were prepared using the hydrothermal or water-bathing method under different conditions. It is shown that the α-MnO 2, ε-MnO 2, and β-MnO 2 catalysts possessed a surface area of ca. 53, 30, and 114 m 2/g, respectively. The oxygen adspecies concentration and low-temperature reducibility decreased in the order of α-MnO 2 > ε-MnO 2 > β-MnO 2, coinciding with the sequence of their catalytic activities for toluene combustion. The well-defined morphological MnO 2 catalysts performed much better than the bulk counterpart. At a space velocity of 20,000 mL/(g h), the temperature for 90% toluene conversion was 238, 229, and 241 °C over α-MnO 2, ε-MnO 2, and β-MnO 2, respectively. The apparent activation energies of α-MnO 2, ε-MnO 2, and β-MnO 2 were in the range of 20-26 kJ/mol. It is concluded that higher oxygen adspecies concentrations and better low-temperature reducibility were responsible for the good catalytic performance of the α-MnO 2, ε-MnO 2, and β-MnO 2 materials.
AB - The rod-like tetragonal α-MnO 2, flower-like hexagonal ε-MnO 2, and dumbbell-like tetragonal β-MnO 2 were prepared using the hydrothermal or water-bathing method under different conditions. It is shown that the α-MnO 2, ε-MnO 2, and β-MnO 2 catalysts possessed a surface area of ca. 53, 30, and 114 m 2/g, respectively. The oxygen adspecies concentration and low-temperature reducibility decreased in the order of α-MnO 2 > ε-MnO 2 > β-MnO 2, coinciding with the sequence of their catalytic activities for toluene combustion. The well-defined morphological MnO 2 catalysts performed much better than the bulk counterpart. At a space velocity of 20,000 mL/(g h), the temperature for 90% toluene conversion was 238, 229, and 241 °C over α-MnO 2, ε-MnO 2, and β-MnO 2, respectively. The apparent activation energies of α-MnO 2, ε-MnO 2, and β-MnO 2 were in the range of 20-26 kJ/mol. It is concluded that higher oxygen adspecies concentrations and better low-temperature reducibility were responsible for the good catalytic performance of the α-MnO 2, ε-MnO 2, and β-MnO 2 materials.
KW - Hydrothermal preparation method
KW - Manganese oxide catalyst
KW - Toluene combustion
KW - Water-bathing preparation method
KW - Well-defined morphology
UR - http://www.scopus.com/inward/record.url?scp=84863720882&partnerID=8YFLogxK
U2 - 10.1016/j.apcata.2012.05.016
DO - 10.1016/j.apcata.2012.05.016
M3 - Journal article
AN - SCOPUS:84863720882
SN - 0926-860X
VL - 433-434
SP - 206
EP - 213
JO - Applied Catalysis A: General
JF - Applied Catalysis A: General
ER -