| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1998: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
This study was made to prepare metal-carbon composite (MCC) on which metal particles were highly dispersed on the surface of carbon by a new method and to examine the catalytic action of the composite, which is regarded as one of the highest functionality, using reactions of CO2 and NO, with a view to developing a novel technique to convert an environmentally benign wood into a highly functional material.
Cellulose in powdered birch was carboxymethylated (CM), aminoethylated (AE), and diethylaminoethylated (DEAE) and then impregnated with nickel acetate at pH 7. By these procedures, Ni^<2+> was introduced into CM wood by ion-exchange and into AE and DEAE woods through the formation of coordinate bond, respectively. When these nickel-loaded woods were carbonized at about 500℃, chars with fine nickel metal particles of 4-5 nm were produced. The chars accelerated effectively the hydrogenation reaction of CO2 (CO2+4H2→CH4+2H2O) at 300-500℃ by subsequent hydrogen treatment at 420℃ for more t
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han 8 h. That is, the catalytic activities of the three kinds of modified wood chars with nickel (Ni/CMWC, Ni/AEWC, and Ni/DEAEWC) were much higher than those of nickel-loaded raw wood char (Ni/UTWC) and activated carbon (Ni/AC) used for comparison, although were equal or inferior to nickel-loaded alumina (Ni/Al2O3) by 20-30%. However, the activity was CMWC >AEWC > DEAEWC and this order could be explained by different bonding strength between the metal and modified wood to probably determine the thermal stability (degree of sintering or agglomeration) during the above hydrogenation. In addition, both carbonization temperature and the period of hydrogen treatment had great influence on the activities of Ni/CMWC, Ni/AEWC, and Ni/DEAEWC and even Ni/DEAEWC exceed Ni/Al2O3 in the activity after carbonization at 550℃ and the reduction over 24 h. Copper-loaded chars also were prepared in the same manners and methods as those mentioned above, and their catalytic activities were measured in NO reduction reaction (2NO+C→N2+CO2, the range of 100-500℃). The results showed the activity order of CMWC≒AEWC≒DEAEWC>UTWC>AC (>None/UTWC) with excellent performance for the former three. The order was determined by the dispersion of copper metal particles on char, similarly to the dispersion of nickel in the above reaction CO2. It was thus concluded that such wood modifications as CM, AE, and DEAE are effective for producing MCC. Less
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