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Journal of Nanomaterials
Volume 2015 (2015), Article ID 513814, 10 pages
http://dx.doi.org/10.1155/2015/513814
Research Article

Experimental Study on the Deactivating Effect of KNO3, KCl, and K2SO4 on Nanosized Ceria/Titania SCR Catalyst

1South China Institute of Environmental Sciences, The Ministry of Environmental Protection of PRC, No. 7 West Street, Yuancun, Guangzhou 510655, China
2The Key Laboratory of Water and Air Pollution Control of Guangdong Province, No. 7 West Street, Yuancun, Guangzhou 510655, China
3School of Chemical Engineering and Technology, Tianjin University, Tianjin Weijin Road, No. 92, Nankai District 300072, China

Received 29 June 2015; Revised 24 August 2015; Accepted 25 August 2015

Academic Editor: Bao Yu Xia

Copyright © 2015 Xiongbo Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Nanosized Ce/TiO2 is effective in selective catalytic reduction of NO with NH3. The NO conversion of Ce/TiO2 is 93% at 370°C. However, addition of potassium using KNO3, KCl, or K2SO4 as precursors effectively deactivates Ce/TiO2. NO conversion at 370°C is reduced to 45%, 24%, and 16% after addition of KNO3, KCl, and K2SO4, respectively, with a controlled K/Ce molar ration at 0.25. The deactivation may be attributed to the changes in the structural and chemical state of ceria and the degradation of surface acidity. The transformation of amorphous ceria into ceria crystals after potassium addition, together with the decrease of surface defects, is also determined. Oxygen diffusion in the process of ceria reduction is slow, and the redox cycle is slowed down. Moreover, the surface acid sites are markedly destroyed, leading to the reduced capacity of ammonia adsorption. These results may provide useful information for the application and life management of CeO2/TiO2 in potassium-rich environments such as biofuel-fired boilers.