Studies on Adsorption of NO on Cu-ZSM-5/Cordierite and Mechanism of NO Decomposition by IR Spectroscopy
GUAN Naijia 1* , SHAN Xuelei 1, ZENG Xiang 1, XIANG Shouhe 1, Anette TRUNSCHKE 2, Manfred BAERNS 2 (1 Institute of New Catalytic Material Science, College of Chemistry, Nankai University, Tianjin 300071, China; 2 Institute of Applied Chemistry
The adsorption of NO on in situ synthesized Cu ZSM 5/cordierite monolithic catalyst samples with different Si/Al ratios is studied by diffuse reflectance Fourier transform infrared spectroscopy at different NO partial pressure from ω =5×10 -4 to 2×10 -3 and temperatures from 298 K to 773 K. The Cu exists mainly in Cu 2+ state even at room temperature. No Cu +—NO is found under the conditions. Several N 2O species are observed on the catalyst surface as well as on the Cu/cordierite sample. It is supposed that there exists a copper zeolite substrate interaction on the in situ synthesized monolithic catalyst. The band at 2133 cm -1 is attributed to NO +—O lattice and only related to the zeolite matrix. A possible mechanism of NO decomposition over the Cu ZSM 5/cordierite monolithic catalyst is drawn.