LaCoO<SUB>3</SUB> Perovskite 촉매상에서의 NO 환원반응

김영호; 이충균; 이화영; 이현구; 이호인

HWAHAK KONGHAK, Vol.29, No.5, 596-605, October, 1991

Export Citation

LaCoO₃ Perovskite 촉매상에서의 NO 환원반응

NO Reduction on LaCoO₃ Perovskite Catalyst

김영호, 이충균, 이화영, 이현구, 이호인

초록

LaCoO₃ 페롭스카이트형 산화물 촉매에서의 NO 분해 및 환원반응에 미치는 CO의 영향을 초고진공하에서 열탈착 실험을 통하여 조사하였다. 흡착되는 NO중 약 70%는 LaCoO₃ 표면의 Co³⁺에 분자상태로 흡착하였으며, 나머지는 산소결함에 분해흡착하여 표면 complex를 형성하였다. Co³⁺에 분자상태로 흡착한 NO는 그 일부가 450K에서 최대 탈착속도를 보였으며, 나머지는 분해되어 N₂ 및 N₂O를 생성하였다. 선흡착된 CO가 후흡착되는 NO의 분해 및 환원에 큰 영향을 미치지 못한 반면, 후흡착된 α-CO₂로 탈착함으로써 NO의 분해를 촉진하였고, NO의 dimer나 chelate형 흡착물의 산소를 이용하여 후흡착된 β-CO는 β-CO₂를 생성하여 탈착함으로써 N₂의 생성을 촉진하였다.

NO decomposition and NO reduction by CO on LaCoO₃ perovskite catalyst have been studied using the technique of thermal desorption spectrometry(TDS)under ultrahigh vacuum(UHV) condition at the adsorption temperature of 300K. About 70% of NO adsorbed molecularly on Co³⁺ ion, and the others adsorbed dissociatively on oxygen vacancy and formed various surface complexes. A part of NO adsorbed on Co³⁺ showed maximum desorption rate at 450K, and the others decomposed to form N₂ or N₂O. Pre-adsorbed CO gave little effect on NO dissociation, but in the case of pre-adsorption of NO, the post-dosed CO promoted both the dissociation of NO and the formation of N₂. The post-dosed α-CO reacted with NO adsorbed on Co³⁺ and desorbed as α-CO₂ resulting in the enhancement of NO dissociation. And the post-dosed β-CO, which adsorbed on the oxygen of the complex, also promoted the formation of N₂ by desorbing as β-CO₂.

[References]

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Kummer JT, Prog. Energy Combust. Sci., 6, 177 (1980)
Hegedus LL, Summers JC, Schlatter JC, Baron K, J. Catal., 56, 321 (1979)
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김영호, 이호인, 촉매, 6, 20 (1990)
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[Referenced By]

[1] Dwyer FG, Catal. Rev.-Sci. Eng., 6, 261 (1972)

[2] Shelef M, Catal. Rev.-Sci. Eng., 11, 1 (1975)

[3] Kummer JT, Prog. Energy Combust. Sci., 6, 177 (1980)

[4] Hegedus LL, Summers JC, Schlatter JC, Baron K, J. Catal., 56, 321 (1979)

[5] Libby WF, Science, 171, 499 (1971)

[6] Voorhoeve RJH, Remeika JP, Trimble LE, "The Catalytic Chemistry of Nitrogen Oxides," Plenum, pp. 215-233, New York, N.Y. (1975)

[7] Voorhoeve RJH, "Advanced Materials in Catalysis," Burton, J.J. and Garten, R.L., (eds.), Academic Press, Chap. 5, New York, N.Y. (1977)

[8] Kim JB, Lee WY, Rhee HK, Lee HI, HWAHAK KONGHAK, 26(5), 535 (1988)

[9] Tak YS, Lee GD, Lee WY, Lee HI, HWAHAK KONGHAK, 26(6), 641 (1988)

[10] 김영호, 이호인, 촉매, 6, 20 (1990)

[11] Park YS, Lee WY, Rhee HK, Sung BP, Lee HI, Korean J. Chem. Eng., 3(2), 165 (1986)

[12] 이충균, 공학석사학위논문, 서울대학교 (1985)

[13] Park YS, Lee HI, HWAHAK KONGHAK, 23(2), 79 (1985)

[14] Voorhoeve RJH, Johnson DW, Remeika JP, Gallagher PK, Science, 195, 827 (1977)

[15] Shelef M, Kummer JT, Chem. Eng. Prog., 67, 74 (1971)

[16] Kugler EL, Kadet AB, Gryder JW, J. Catal., 41, 72 (1976)

[17] Yao HC, Shelef M, J. Catal., 31, 377 (1973)

[18] Redhead PA, Vacuum, 12, 203 (1962)

[19] Hendershot RE, Hansen RS, J. Catal., 98, 150 (1986)

[20] Voorhoeve RJH, Remeika JP, Trimble LE, Ann. N.Y. Acad. Sci., 272, 3 (1976)

[21] Sorenson SC, Wronkiewicz JA, Sis LB, Wirtz GP, Ceram. Bull., 53, 446 (1974)

[22] DeLouise LA, Winograd N, Surf. Sci., 159, 199 (1985)