Development of cerium-based catalysts for selective catalytic reduction of nitrogen oxides: a review

Abstract

Nitrogen oxides (NO_X) are major pollutants of the atmosphere, and selective catalytic reduction of nitrogen oxides using ammonia as a reductant (NH₃-SCR) is an effective method to remove nitrogen oxides. Numerous catalysts have been studied and used for the elimination of nitrogen oxides. These studies have revealed that cerium-based catalysts provide the advantage of wide operating temperature windows and high catalytic activities in NH₃-SCR reactions, and the activity and structure of cerium-based catalysts are related to the preparation methods. In this review, we have summarized the development of cerium-based composite catalysts and elaborated on the performance, mechanism, and synthesis methods of cerium-based catalysts for NH₃-SCR reactions. The purpose of this review was to highlight (1) the influence of the preparation method on the structure and catalytic performance of ceria-based catalysts; (2) the reaction mechanism of NH₃-SCR deNO_X over cerium-based catalysts; and (3) the design strategies of catalysts to achieve wide operating temperature windows and high catalytic activities in NH₃-SCR deNO_X reactions.