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Indexed by:期刊论文

Date of Publication:2012-05-01

Journal:JOURNAL OF NATURAL GAS CHEMISTRY

Included Journals:SCIE、EI、ISTIC、CSCD

Volume:21

Issue:3

Page Number:332-338

ISSN No.:1003-9953

Key Words:NOx removal; NO oxidation; nitrate species; Ce-Al2O3; acetylene

Abstract:Ce-Al2O3 catalysts prepared by co-precipitation are investigated both in NO oxidation by O-2 and in selective catalytic reduction of NO by C2H2 (C2H2-SCR). It is found that C2H2-SCR is initiated and controlled by NO oxidation to NO2 over Al2O3. Ce loading on Al2O3 is almost inactive for NO oxidation below 350 degrees C, since NO2 strongly adsorbs on cerium oxide, leading to the active sites being blocked, which was characterized by temperature-programmed desorption of NO and NO2 and Fourier transform infrared spectroscopy after NO+O-2 coadsorption over the samples. However, in the case of C2H2-SCR, Ce loading on Al2O3 significantly improves the reaction by accelerating the NO oxidation step in the temperature range of 250-450 degrees C, since the nitrate species produced by NO2 adsorption is an active intermediate required by C2H2-SCR.