Catalytic Activity and Surface Characteristics of WO3-doped MnOx-TiO2 Catalysts for Low-temperature Selective Catalytic Reduction of NOx with NH3 |
Byeongkil Shin1, Heesoo Lee2, Hyun Park1 |
1Global Core Research Center for Ships and Offshore Plants (GCRC-SOP), Pusan National University, Busan 46241, Republic of Korea 2School of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of Korea |
|
Received: 6 January 2016; Accepted: 5 April 2016. Published online: 5 October 2016. |
|
| |
ABSTRACT |
The effect of added WO3 on the catalytic activity and surface characteristics of the MnOx-TiO2 system was investigated for the low-temperature selective catalytic reduction of NOx with NH3. Based on physio-chemical characterizations, the specific surface areas of the WO3-MnOx-TiO2 catalysts increased from 76.12 m2/g to 90.29 m2/g as the WO3 content increased, and the crystallinity of the anatase TiO2 phase decreased. The NOx conversion efficiency of the WO3-MnOx-TiO2 catalysts with WO3 content was over 70% at 200 °C, and their efficiency was over 90% at 300 °C. The results of Fourier transform infrared spectroscopy indicated that the 1438 and 1632 cm-1 values, which were assigned to Lewis and Brønsted acid sites, increased with the increase in WO3 content. The enhanced catalytic acidity originated from changes to the physical and chemical structures on the surface. MnOx formed on the TiO2 surface of the 15 wt% WO3-doped MnOx-TiO2, and amorphous state Mn2O3 (Mn3+) and WO3 (W6+) existed on the surface, which led to the improved Lewis and Brønsted acid sites, respectively. |
Keywords:
nanostructured materials, sol-gel, surface, raman spectroscopy, catalytic acidity |
|
|
|