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

The Korea Association of Crystal Growth (한국결정성장학회)
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Synthesis of WO3/TiO2 catalysts from different tungsten precursors and their catalytic performances in the SCR

텅스텐(W) 원료에 따른 WO3/TiO2 SCR 촉매의 제조 및 촉매능

  • Lee, Byeong Woo (Department of Materials Engineering, Korea Maritime University) ;
  • Lee, Jin Hee (Department of Materials Engineering, Korea Maritime University)
  • 이병우 (한국해양대학교 재료공학과) ;
  • 이진희 (한국해양대학교 재료공학과)
  • Received : 2014.08.05
  • Accepted : 2014.09.26
  • Published : 2014.10.31
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Abstract

An investigation of the influence of $WO_3$ addition with different precursors and preparation methods on the phase formation and selective catalytic reduction (SCR) efficiency of anatase-$TiO_2$ powders has been carried out. An anatase-$TiO_2$ synthesized by precipitation process was used as a catalyst support. For $WO_3(10wt%)/TiO_2$, the W loading to the $TiO_2$ support led to the lower in anatase to rutile transition temperature to ${\sim}900^{\circ}C$ from $1200^{\circ}C$ of the $TiO_2$ support alone. In the case of $WO_3(10wt%)/TiO_2$ SCR powders obtained from a wet process with ammonium meta-tungstate (AMT) precursor, the highest $NO_X$ conversion efficiency was achieved at $450^{\circ}C$ remaining high efficiency at $500^{\circ}C$, while the same composition prepared from a dry process with $WO_3$ addition showed the lowered efficiency with temperature after reaching the efficiency maximum at $350^{\circ}C$. The same tendency has been found that the $V_2O_5(5wt%)-WO_3(10wt%)/TiO_2$ SCR powders obtained from the wet process with AMT precursor has shown the superior $NO_X$ conversion efficiency over 90 % in a wider temperature range of $300{\sim}500^{\circ}C$.

Anatase $TiO_2$에 각기 다른 텅스텐(W) 함유원료와 제조방법을 적용하여 $WO_3$ 촉매가 첨가된 SCR(selective catalytic reduction)용 분말을 합성하였으며, W 촉매 첨가가 합성분말의 상합성 및 SCR 촉매능에 미치는 영향에 대해 연구하였다. 촉매의 지지체인 $TiO_2$는 침전법으로 anatase 상으로 합성되었으며, anatase에서 고온상인 rutile로의 상전이 온도는 $1200^{\circ}C$였으나, $WO_3$를 10 wt% 첨가할 경우 이 상전이 온도는 $900^{\circ}C$로 낮아졌다. 건식으로 $WO_3$ 분말을 직접 첨가하여 $WO_3(10wt%)/TiO_2$를 제조한 경우 $350^{\circ}C$에서 $NO_X$ 제거 촉매능이 최고점에 이르나 온도증가에 따라 그 효율이 상당히 감소하였다. 암모늄-메타-텅스테이트를 습식으로 첨가하여 제조한 경우, 보다 고온인 $450^{\circ}C$에서 촉매능이 최고점에 이르렀으며 온도에 따른 효율감소 폭도 적었다. 이와 같은 경향은 $WO_3$와 $V_2O_5$를 동시 첨가하여 제조한 $V_2O_5(5wt%)-WO_3(10wt%)/TiO_2$ 촉매에서도 나타났다. 즉, 암모늄-메타-텅스테이트를 습식으로 첨가한 경우, $WO_3$를 직접 첨가한 경우에 비해 넓은 온도범위($300^{\circ}C{\sim}500^{\circ}C$)에 걸쳐 90 %에 이상의 우수한 $NO_X$ 변환효율을 보였다.

Keywords

References

  1. A. Fujishima, T.N. Rao and D.A. Truk, "Titanium dioxide photocatalysis", J. Photochem. Photobiol. C: Photochem. Rev. 1 (2000) 1. https://doi.org/10.1016/S1389-5567(00)00002-2
  2. D. Dong, P. Li, X. Li, C. Xu, D. Gong, Y. Zhanga, Q. Zhao and P. Li, "Photocatalytic degradation of phenanthrene and pyrene on soil surfaces in the presence of nanometer rutile $TiO_2$ under UV-irradiation", Chem. Engin. J. 158 (2010) 378. https://doi.org/10.1016/j.cej.2009.12.046
  3. V. Puddu, R. Mokaya and G.L. Puma, "Novel one step hydrothermal synthesis of $TiO_2/WO_3$ nanocomposites with enhanced photocatalytic activity", Chem. Commun. 45 (2007) 4749.
  4. W. Smith, A. Wolcott, R.C. Fitzmorris, J.Z. Zhang and Y.P. Zhao, "Quasi-core-shell $TiO_2/WO_3$ and $WO_3/TiO_2$ nanorod arrays fabricated by glancing angle deposition for solar water splitting", J. Mater. Chem. 21 (2011) 10792. https://doi.org/10.1039/c1jm11629k
  5. G. Busca, L. Lietti, G. Ramis and F. Berti, "Chemical and mechanical aspects of the selective catalytic reduction of NOx by ammonia over oxide catalysts: A review", Appl. Catal. B: Envir. 18 (1998) 1. https://doi.org/10.1016/S0926-3373(98)00040-X
  6. K. Bourikas, Ch. Fountzoula and Ch. Kordulis, "Monolayer transition metal supported on titania catalysts for the selective catalytic reduction of NO by $NH_3$", Appl. Catal. B: Envir. 52 (2004) 145. https://doi.org/10.1016/j.apcatb.2004.04.001
  7. A. Andersson and S.L.T. Anderson, in: R.K. Grasselli and J.F. Brazdil (Eds), "Solid state chemistry in catalysis" (ACS, Washington, 1985).
  8. A.M. Efstathiou and K. Fliatoura, "Selective catalytic reduction of nitric oxide with ammonia over $V_2O_5/TiO_2$ catalyst: A steady-state and transient kinetic study", Appl. Catal. B: Envir. 6 (1995) 35. https://doi.org/10.1016/0926-3373(94)00062-X
  9. R.Q. Long and R.T. Yang, "Selective catalytic reduction of NO with ammonia over $V_2O_5$ doped $TiO_2$ pillared clay catalysts", Appl. Catal. B: Envir. 24 (2000) 13. https://doi.org/10.1016/S0926-3373(99)00092-2
  10. L. Lietti, J.L. Alemany, P. Forzatti, G. Busca, G. Ramis, E. Giamello and F. Bregani, "Reactivity of $V_2O_5$-$WO_3/TiO_2$ catalysts in the selective catalytic reduction of nitric-oxide by ammonia", Catal. Today 29 (1996) 143. https://doi.org/10.1016/0920-5861(95)00250-2
  11. R. Khodayari and C.U. Ingemar Odenbrand, "Regeneration of commercial $TiO_2$-$V_2O_5$-WO3 SCR catalysts used in bio fuel plants", Appl. Catal. B: Envir. 30 (2001) 87. https://doi.org/10.1016/S0926-3373(00)00227-7
  12. S. Djerad, L. Tifouti, M. Crocoll and W. Weisweiler, "Effect of vanadia and tungsten loadings on the physical and chemical characterization of $V_2O_5$-$WO_3/TiO_2$ catalysts", J. Mol. Catal. A: Chem. 208 (2004) 257. https://doi.org/10.1016/j.molcata.2003.07.016
  13. B.W. Lee, H. Cho and D.W. Shin, "Characterization and De-NOX activity of binary $V_2O_5/TiO_2$ and $WO_3/TiO_2$, and ternary $V_2O_5$-$WO_3/TiO_2$ SCR catalysts", J. Ceram. Proc. Res. 8 (2007) 203.