Cerium Oxide-Based Catalysts for Low-Temperature Selective Catalytic Reduction of NOx with NH3: A Review

The selective catalytic reduction (SCR) of NOx with ammonia is an effective method to remove NOx from stationary and mobile sources. Cerium oxides (CeOx) have been studied extensively as low-temperature SCR catalysts since they manifest prominent oxygen storage capacity in catalysis. This paper reviews the recent progress on the Ce-based catalysts for low-temperature SCR de-NOx with NH3, including three categories, single CeOx, Ce-based multimetal oxide, and Ce-based multimetal oxides with support. In the section on single CeOx, the reasons for the significant catalytic activity and the function of CeOx in the catalytic reactions are systematically reviewed. For multimetal oxide catalysts, the various roles played by the components of catalysts are summarized from several aspects. In the introduction of supported metal oxide catalysts, according to the type of support, the function of each support in the reaction is analyzed methodically. Additionally, we investigated the reaction mechanism of low-temperature SCR of NOx, including Eley–Rideal (E–R) and Langmuir–Hinshelwood (L–H) mechanisms. Finally, the development outlook and direction of the application of cerium oxide-based catalysts in the field of low-temperature SCR of NOx is prospected.