| Search / Korean Journal of Chemical Engineering |
Korean Chemical Engineering Research,
Vol.42, No.2, 144-150, 2004
Vol.42, No.2, 144-150, 2004
Methane의 CO2 Reforming 반응에 대한 Pt/CexZr1-xO2(x=0, 0.5, 1)의 환원-산화특성과 반응성
Redox Property and Reactivity of Pt/CexZr1-xO2(x=0, 0.5, 1) for CO2 Reforming of Methane
CeO2, Ce0.5Zr0.5O2, ZrO2에 각각 0.5 wt%의 백금을 담지시킨 촉매의 환원-산화특성과 CH4의 CO2 reforming에 대한 반응성간의 상관관계를 조사하였다. 촉매의 환원-산화 특성은 600 ℃에서의 CO-O2 및 CO-CO2 cyclic pulse 실험에 의하여 Pt/Ce0.5Zr0.5O2>Pt/CeO2≫Pt/ZrO2의 순서를 나타낸 반면, CH4의 CO2 reforming 반응성은 550-650 ℃에서 양론비로 혼합된 CH4과 CO2 pulse에 대하여 Pt/ZrO2>Pt/Ce0.5Zr0.5O2>Pt/CeO2의 순서를 나타내었다. 상대적으로 비환원성인 Pt/ZrO2가 환원-산화 특성이 뛰어난 Pt/Ce0.5Zr0.5O2보다 높은 반응성을 가진다는 사실로부터 Pt/ZrO2가 Pt/Ce0.5Zr0.5O2또는 Pt/CeO2와는 다른 반응기구를 따른다는 것을 알 수 있다. Pt/ZrO2는 처음부터 일정한 수준의 반응성을 나타낸 반면, Pt/Ce0.5Zr0.5O2와 Pt/CeO2는 촉매의 환원 상태에 따라서 반응성이 변화하였다. Pt/Ce0.5Zr0.5O2는 노은 산소 유동성 때문에 반응초기에는 CH4의 완전산화 반응이 오히려 지배적이었으나, 반응기체 pulse 주입 횟수가 증가함에 따라서 CH4의 CO2 reforming에 대한 선택도가 증가하여 일정한 수준에 도달하였다.
Relationship between the redox property and the reactivity for CO2 reforming of methane was investigated on 0.5 wt% platinum-impregnated CeO2, Ce0.5Zr0.5O2 and ZrO2. Whereas CO-O2 and CO-CO2 cyclic pulse experiments at 600 ℃ showed that the redox property was in the order of Pt/Ce0.5Zr0.5O2>Pt/CeO2>>Pt/ZrO2, the reactivity for CO2 reforming of methane was in the order of Pt/ZrO2>Pt/Ce0.5Zr0.5O2>Pt/CeO2 by pulse experiments at 550-650 ℃ with stoichiometric mixture of the reactants. From the fact that relatively irreducible Pt/ZrO2 exhibited higher reactivity than Pt/Ce0.5Zr0.5O2 possessing more vigorous redox property, it could be deduced that Pt/ZrO2 follows the reaction mechanism unequal to that for Pt/Ce0.5Zr0.5O2 or Pt/CeO2. While the reactivity of Pt/ZrO2 reached a steady level from the beginning, the reactivity of Pt/Ce0.5Zr0.5O2 and Pt/CeO2 varied with the extent of catalyst reduction. Complete oxidation of methane was initially more dominant on Pt/Ce0.5Zr0.5O2 due to its vigorous oxygen mobility, however, the selectivity toward CO2 reforming of methane increased with the number of reactant pulses before it reached a steady level.
Keywords:
Redox Property; CO2 Reforming of Methane; Cyclic Pulse Experiments; Stoichiometric Reactant Mixture; Reaction MEchanism; Oxygen Mobility
[References]
- Asami K, Li XH, Fujimoto K, Koyama Y, Sakurama A, Kometani N, Yonezawa Y, Catal. Today, 84(1-2), 27, 2003
- Stagg-Williams SM, Noronha FB, Fendley G, Resasco DE, J. Catal., 194(2), 240, 2000
- Bitter JH, Seshan K, Lercher JA, J. Catal., 171(1), 279, 1997
- Bradford MCJ, Vannice MA, J. Catal., 173(1), 157, 1998
- Bradford MCJ, Vannice MA, Catal. Today, 50(1), 87, 1999
- Sharma S, Hilaire S, Vohs JM, Gorte RJ, Jen HW, J. Catal., 190(1), 199, 2000
- Stagg SM, Romeo E, Padro C, Resasco DE, J. Catal., 178(1), 137, 1998
- Bitter JH, Seshan K, Lercher JA, J. Catal., 183(2), 336, 1999
- Vankeulen AN, Seshan K, Hoebink JH, Ross JR, J. Catal., 166(2), 306, 1997
- Noronha FB, Fendley EC, Soares RR, Alvarez WE, Resasco DE, Chem. Eng. J., 82(1-3), 21, 2001
- Kaspar J, Fornasiero P, Graziani M, Catal. Today, 50(2), 285, 1999
- Pantu P, Kim K, Gavalas GR, Appl. Catal. A: Gen., 193(1-2), 203, 2000
- Fornasiero P, Dimonte R, Rao GR, Kaspar J, Meriani S, Trovarelli A, Graziani M, J. Catal., 151(1), 168, 1995
- Fornasiero P, Balducci G, Dimonte R, Kaspar J, Sergo V, Gubitosa G, Ferrero A, Graziani M, J. Catal., 164(1), 173, 1996
- Holmgren A, Andersson B, J. Catal., 178(1), 14, 1998
- Costa CN, Christoua SY, Georgiou G, Efstathiou AM, J. Catal., 219(2), 259, 2003
참고문헌정보(참고문헌, 인용문헌)는 화학공학소재연구정보센터에 의해 제공되고 있습니다.