The CeO₂/TiO₂ catalyst was prepared by a deposition-precipitation method, which exhibited high low-temperature activity under the fast SCR condition. By using transient reaction analysis (TRA), the steps in the fast SCR, including NO₂ adsorption and decomposition, reaction between nitrates and NO, ammonium nitrate formation and reduction by NO, were investigated. Diffuses reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments, via NO + O₂ or NO + NO₂ adsorption, ammonium species reaction with NO_x and NO reaction with NH₄NO₃, were designed to identify the roles of NO, NO₂ and NH₃ in fast SCR. Based on L-H mechanism, the NH₄NO₃ formation played an important role in low-temperature SCR reaction. Compared with the behavior in standard SCR, the higher activity in the presence of NO₂ was ascribed to the faster NH₄NO₃ formation rate and larger amounts of nitrates/nitrites. This phenomenon provided a basis for developing Ce-based catalysts as SCR catalysts for diesel exhaust aftertreatment.

CeO ₂ / TiO ₂催化剂采用沉积沉淀法制备，在快速SCR条件下具有较高的低温活性。通过瞬态反应分析（TRA），研究了快速SCR中的步骤，包括NO _2的吸附和分解，硝酸盐与NO之间的反应，硝酸铵的形成以及NO的还原。通过NO + O ₂或NO + NO ₂吸附，铵种与NO _x的反应以及NO与NH ₄ NO _3的反应，设计了漫反射红外傅里叶变换光谱（DRIFTS）实验，以确定NO，NO ₂和NO的作用。NH₃在快速SCR中。基于LH机理，NH ₄ NO _3的形成在低温SCR反应中起重要作用。与标准SCR的行为相比，NO ₂存在下的较高活性归因于更快的NH ₄ NO ₃形成速率和大量的硝酸盐/亚硝酸盐。该现象为开发基于Ce的催化剂作为柴油机废气后处理的SCR催化剂提供了基础。