关键词:

原位漫反射红外光谱, 选择性催化还原, CuO/γ-Al₂O₃, NH₃, NO, 吸附

Abstract:

Granular CuO/γ-Al₂O₃ catalysts were synthesized by the sol-gel method.The performance of CuO/γ-Al₂O₃ catalysts for selective catalytic reduction（SCR）was analyzed in a fixed bed adsorption system.The optimum temperature range for SCR reaction on CuO/γ-Al₂O₃ catalyst was 250—450℃.Based on the previous study，CuO/γ-Al₂O₃ catalysts were investigated with in-situ diffuse reflectance infrared fourier transform spectroscopy（DRIFTS）for revealing the reaction mechanism.The DRIFTS indicated both coordinated NH3 and NH⁺₄ were present on the catalysts.NO and NO₂ could be adsorbed on the catalyst surface and produce a number of different transformation species.Formation of NO-₃ after O₂ addition suggested the oxidation of adsorbed NO species to nitrates.When NO was introduced into the samples with pre-adsorbed NH₃+O₂，the coordinated NH₃ on the catalyst surface was consumed rapidly.But NH⁺₄ was not consumed under the SCR reaction.It indicated that these coordinated NH₃ species could react with NO effectively.When NH₃ was introduced into the samples with pre-adsorbed NO+O₂，the intensity of adsorbed NO species did not change; it inferred that SCR reaction would not proceed.It was found that the SCR reaction could take place between the adsorbed NH3 and gaseous NO.The adsorbed NO and formed NO^-₂ and NO^-₃ species did not participate in the SCR reaction.

Key words:

原位漫反射红外光谱, 选择性催化还原, CuO/γ-Al₂O₃, NH₃, NO, 吸附