Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
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Physico-chemical effects of cerium oxide on catalytic activity of CeO2-TiO2 prepared by sol-gel method for NH3-SCR

CeO2가 졸겔법으로 합성한 CeO2-TiO2계 SCR용 촉매의 활성에 미치는 물리화학적 영향

  • Kim, Buyoung (School of Materials Science & Engineering, Pusan National University) ;
  • Shin, Byeongkil (School of Materials Science & Engineering, Pusan National University) ;
  • Lee, Heesoo (School of Materials Science & Engineering, Pusan National University) ;
  • Chun, Ho Hwan (Department of Naval Architecture & Ocean Engineering, Pusan National University)
  • Received : 2013.10.14
  • Accepted : 2013.11.08
  • Published : 2013.12.31
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Abstract

The effects of $CeO_2$ on catalytic activity of $CeO_2-TiO_2$ for the selective catalytic reduction (SCR) of $NO_x$ were investigated in terms of structural, morphological, and physico-chemical analyseis. $CeO_2-TiO_2$ catalysts were synthesized with three different additions, 10, 20, and 30 wt% of $CeO_2$, by the sol-gel method. The XRD peaks of all specimens were assigned to a $TiO_2$ phase (anatase) and the peaks became broader with the addition of $CeO_2$ because it was dispersed as an amorphous phase on the surface of $TiO_2$ particles. The specific surface area of $TiO_2$ increased with the addition of $CeO_2$ from $60.6306m^2/g$ to $116.2791m^2/g$ due to suppression of $TiO_2$ grain growth by $CeO_2$. The 30 wt% $CeO_2-TiO_2$ catalyst, having the strongest catalytic acid sites ($Br{\Phi}nsted$ and Lewis), showed the highest $NO_x$ conversion efficiency of 98 % at $300^{\circ}C$ among the specimens. It was considered that $CeO_2$ contributes to the improvement of the $NO_x$ conversion of $CeO_2-TiO_2$ catalyst by increasing specific surface area and catalytic acid sites.

$CeO_2$의 첨가가 $CeO_2-TiO_2$계 SCR촉매 활성에 미치는 영향을 구조적, 형상학적, 물리화학적 분석을 통해 규명하였다. 순수한 $TiO_2$ 분말과 10, 20, 30 wt%의 $CeO_2$를 첨가한 $CeO_2-TiO_2$ 분말을 졸겔법으로 합성한 결과, 분말 모두 $TiO_2$의 아나타제 (anatase)상을 나타내었고 $CeO_2$를 첨가할수록 $TiO_2$ 표면에 결정성이 낮은 $CeO_2$가 분산되어 피크강도가 낮아짐을 확인하였다. 순수한 $TiO_2$의 비표면적이 $60.6306m^2/g$인데 반해 $CeO_2-TiO_2$의 비표면적은 30 wt%의 $CeO_2$를 첨가한 경우 $116.2791m^2/g$으로 비표면적이 증가하였고 따라서 첨가된 $CeO_2$가 $TiO_2$의 응집을 억제한 것으로 예상된다. $NO_x$ 제거효율은 30 wt% $CeO_2-TiO_2$ 촉매가 $300^{\circ}C$에서 98 %로 다른 분말보다 높은 효율을 나타내는데 이는 FT-IR을 이용하여 촉매의 산점 변화를 확인한 결과 30 wt% $CeO_2-TiO_2$ 분말의 경우가 다른 분말들에 비해 산점이 상대적으로 많았기 때문이다. 따라서 졸겔법으로 합성한 SCR용 $CeO_2-TiO_2$계 촉매에서 $CeO_2$의 첨가는 $TiO_2$의 입성장을 억제하여 비표면적을 증가시키고 $Br{\Phi}nsted$ 및 Lewis 산점을 증가시킴으로써 촉매 효율을 향상시켰다고 판단된다.

Keywords

References

  1. Y. Traa, B. Burger and J. Weitkamp, "Zeolite-based materials for the selective catalytic reduction of $NO_x$ with hydrocarbons", Microporous Mater. 30 (1999) 3. https://doi.org/10.1016/S1387-1811(99)00030-X
  2. M.C. Shin, J.H. Kim, J.S. Cha, B.K. Shin and H.S. Lee, "Powder characteristics and catalytic activity of $CeO_2/TiO_2 $ catalysts prepared by the sol-gel method for SCR of $NO_x$", Korean J. Met. Mater. 51 (2013) 57. https://doi.org/10.3365/KJMM.2013.51.1.057
  3. S. Djerad, M. Crocoll, S. Kureti, L. Tifouti and W. Weisweiler, "Effect of oxygen concentration on the $NO_x$ reduction with ammonia over $V_2O_5-WO_3/TiO_2$ catalyst", Catal. Today 113 (2006) 208. https://doi.org/10.1016/j.cattod.2005.11.067
  4. Y. Komatsubara, S. Ida, H. Fujitsu and I. Mochida, "Catalytic activity of PAN-based active carbon fibre (PAN-ACF) activated with sulphuric acid for reduction of nitric oxide with ammonia", Fuel 63 (1984) 1738. https://doi.org/10.1016/0016-2361(84)90110-8
  5. K. Kusakabe, M. Kashima, S. Morooka and Y. Kato, "Rate of reduction of nitric oxide with ammonia on coke catalysts activated with sulphuric acid", Fuel 67 (1988) 714. https://doi.org/10.1016/0016-2361(88)90304-3
  6. E. Richter, H.J. Schmidt and H.G. Schecker, "Adsorption and catalytic reactions of NO and $NH_3$ on activated carbon", Chem. Eng. Technol. 13 (1990) 332. https://doi.org/10.1002/ceat.270130146
  7. X. Tang, J. Hao, W. Xu and J. Li, "Low temperature selective catalytic reduction of $NO_x$ with $NH_3$ over amorphous MnOx catalysts prepared by three methods", Catal. Commun. 8 (2007) 329. https://doi.org/10.1016/j.catcom.2006.06.025
  8. G. Ramis, L. Yi, G. Busca, M. Turco, E. Kotur and R.J. Willey, "Adsorption, activation, and oxidation of ammonia over SCR catalysts", J. Catal. 157 (1995) 523. https://doi.org/10.1006/jcat.1995.1316
  9. F. Liu, H. He and C. Zhang, "Novel iron titanate catalyst for the selective catalytic reduction of NO with $NH_3$ in the medium temperature range", Chem. Commun. (2008) 2043.
  10. W. Xu, Y. Yu, C. Zhang and H. He, "Selective catalytic reduction of NO by $NH_3$ over a $Ce/TiO_2$ catalyst", Catal. Commun. 9 (2008) 1453. https://doi.org/10.1016/j.catcom.2007.12.012
  11. B.M. Reddy, A. Khan, Y. Yamada, T. Kobayashi, S. Loridant and J.C. Volta, "Structural characterization of $CeO_2TiO_2$ and $V_2O_5/CeO_2TiO_2$ catalysts by raman and XPS techniques", J. Phys. Chem. B 107 (2003) 5162. https://doi.org/10.1021/jp0344601
  12. T.H. Kang, S.M. Koo, C.H. Jung, K.T. Hwang and W.K. Kang, "Synthesis of nano Cerium(IV) oxide from recycled Ce precusor", J. Korean Cryst. Growth Cryst. Technol. 23 (2013) 101. https://doi.org/10.6111/JKCGCT.2013.23.2.101
  13. G. Xiang, J. Ye, Z. Yi, L. Zhongyang and C. Kefa, "The activity and characterization of $CeO_2-TiO_2$ catalysts prepared by the sol-gel method for selective catalytic reduction of NO with $NH_3$", J. Hazard. Mater. 174 (2010) 734. https://doi.org/10.1016/j.jhazmat.2009.09.112
  14. R. Jin, Y. Liu, Z. Wu, H. Wang and T. Gu, "Low-temperature selective catalytic reduction of NO with $NH_{(3)}$ over Mn-Ce oxides supported on $TiO_2$ and $Al_2O_3$: a comparative study", Chemosphere 78 (2010) 1160. https://doi.org/10.1016/j.chemosphere.2009.11.049
  15. D.A. Pena, B.S. Uphade, E.P. Reddy and P.G. Smirniotis, "Identification of surface species on titania-supported manganese, chromium, and copper oxide low temperature SCR catalysts", J. Phys. Chem. B 108 (2004) 9927. https://doi.org/10.1021/jp0313122
  16. S.H. Yoon, J.H. Kim, B.K. Shin, S.S. Park, D.W. Shin and H.S. Lee, "Effects of anatase-rutile phase transition and grain growth with $WO_3$ on thermal stability for $TiO_2$ SCR catalyst", J. Korean Cryst. Growth Cryst. Technol. 21 (2011) 181. https://doi.org/10.6111/JKCGCT.2011.21.4.181

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