A novel CNTs functionalized CeO2/CNTs–GAC catalyst with high NO conversion and SO2 tolerance for low temperature selective catalytic reduction of NO by NH3

Abstract

Low−temperature selective catalytic reduction of NOx by NH3 (NH3−SCR) for diminishing SO2 poisoning remains an issue in flue gas denitrification (DeNOx). Herein, A novel CNTs functionalized low temperature NH3−SCR catalyst CeO2/CNTs−GAC was prepared, which showed high NO conversion activity (100% at 150 °C) and SO2 resistance. The addition of CNTs restrained SO2 adsorption but improved the selective adsorption of NO, which restricted the deposition of (NH4)2SO4 and/or Ce2(SO4)3, and resulted in high SO2 resistance. The addition of CNTs facilitated the diffusion and transportation of NH3 and NO, and the electron transfer on CeO2/CNTs−GAC, leading to higher content of Ce3+ and adsorbed O species on the CeO2/CNTs−GAC surface and promoted formation of surface-adsorbed oxygen OA. Therefore, CeO2/CNTs−GAC provided abundant NO adsorption and activation sites, facilitating “fast SCR” reaction and enhancing the NH3−SCR reaction. The proposed CeO2/CNTs−GAC catalyst exhibited higher NH3−SCR activity, N2 selectivity, catalytic durability and SO2 resistance than CeO2/GAC.