Microstructure of Porous V₂O-CeO₂-SiO₂ Catalyst for SCR of NO with NH₃ at Low Temperature

Abstract:

Selective catalytic reduction (SCR) is a well-proven method to reduce NO emission. However, to choose the right catalyst that provides a surface for reaction between NO and ammonia at low temperatures is a challenging task for a catalysts developers. In an earlier study, we prepared V₂O₅-CeO₂-SiO₂ catalyst with increasing V₂O₅ content by sol-gel route and found that the catalytic activity improved with increasing the V₂O₅ loading up to 0.5%. The catalytic activity, however, dropped when V₂O₅ loading was about 1% and increased back when the loading of V₂O₅ was about 5%. In this study, we looked into the microstructural relationship to explain these findings. The microstructures of the catalysts before and after exposure to NO gas revealed that the catalysts with 0.2% and 0.5% V₂O₅ were more porous after the reduction process possibly due to improved breakdown of (NH₄)HCO₃ to NH₃ by the possible interaction with the V₂O₅ and CeO₂-containing catalysts which consequently resulted in a more efficient NO reduction to N₂ and H₂O at low temperature. The microstructure of the catalyst with 1% V₂O₅ content to 5%, improved back the efficiency although clogging by CeVO₄ phase still possible due to its presence based on XRD. The well-ordered micropores before exposure to NO and the more efficient breakdown of (NH₄)HCO₃ could have contributed to increase back the catalytic activity at low temperature.

• Periodical: Advanced Materials Research (Volumes 875-877)
• Pages: 213-217
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.875-877.213
• Online since: February 2014
• Authors: Mohd Razali Sohot, Umi Sarah Jais, Muhd Rosli Sulaiman
• Keywords: Catalyst, Microstructure, NO, SiO₂, V₂O₅

References

[1] H. Yan, T. Zhi-quan, W. Bing, and Z. Jun-feng, Low temperature selective catalytic reduction of NO by ammonia over V2O5-CeO2/TiO2, J Fuel Chem Technol, 2008, 36(5), 616−620, (2008).

DOI: 10.1016/s1872-5813(08)60036-5

[2] Latif Ahmad, C. Peng Leo, S. Rizal. Vanadium oxide supported y-alumina with bimodal porous structure for intra-particle diffusion enhancement in styrene oxidation reaction. J porous mater 16: 33-40 (2009).

DOI: 10.1007/s10934-007-9165-8

[3] Shule Zhang, Hongyu Li, Qin Zhong Promotional effect of F-doped on V2O5-WO3/TiO2 catalyst for NH3-SCR of NO at low-temperature. Applied Catalysis A: General (2012).

DOI: 10.1016/j.apcata.2012.05.049

[4] Junhua Li, Huazhen Chang, Lei Ma, Jiming Hao, Ralph T. Yang. Low-temperature selective catalytic reduction of NOx with NH3 over metal oxide and zeolite catalysts—A review. Catalysis Today 175 147– 156 (2011).

DOI: 10.1016/j.cattod.2011.03.034

[5] Moon Lee, K. Hee Park, S. Chang Hong. MnOx/CeO2–TiO2 mixed oxide catalysts for the selective catalytic reduction of NO with NH3 at low temperature Chemical Engineering Journal 195-196 323–331(2012).

DOI: 10.1016/j.cej.2012.05.009

[6] G. Qi, R. T. Yang, R. Changb. MnOx-CeO2 mixed oxides prepared by co-precipitation for selective catalytic reduction of NO with NH3 at low temperatures. Applied Catalysis B: Environmental 51 93–106 (2004).

DOI: 10.1016/j.apcatb.2004.01.023

[7] L. Liu, Y. Cao, W. Sun, Z. Yao, B. Liu, F. Gao, L. Dong, Morphology and nano size effects of ceria from different precursors on the activity for NO reduction Catalysis Today (2011).

DOI: 10.1016/j.cattod.2011.04.018

[8] V. Pârvulescu, C. Paun, V. Pârvulescu, M. Alifanti, I. Giakoumelou, S. Boghosian, S. B. Rasmussen, K. M. Eriksen, and R. Fehrmann, Vanadia–silica and vanadia–cesium–silica catalysts for oxidation of SO2, Journal of catalysis 225 24–36, (2004).

DOI: 10.1016/j.jcat.2004.03.040

[9] L. Zhu, B. Huang, W. Wang, Z. Wei, D. Ye. Low-temperature SCR of NO with NH3 over CeO2 supported on modified activated carbon fibers. Catalysis Communications 12 394–398 (2011).

DOI: 10.1016/j.catcom.2010.10.028

[10] M. R. Sohot, U. S. Jais, M. R. Sulaiman. Preparation and Performance of V2O5-CeO2-SiO2 Catalyst for the Selective Catalytic Reduction (SCR) of NOx With NH3 at Low Temperature. 2012. Proceeding of ISBEIA - In Press (2012).