The purification of NO_x from diesel engine exhaust is an important topic in the field of air pollution control, which is significant for the improvement of current unban air quality. The selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) is one of the most promising technologies for the control of NO_x emission from diesel engine exhaust. In recent years, Cu-CHA catalysts, which are obtained from loading transition metal Cu on zeolites with chabazite (CHA) structure, have attracted much attention in the field of NH₃-SCR reaction, due to their excellent NH₃-SCR activity and hydrothermal stability. Cu-SSZ-13 and Cu-SAPO-34 are the two typical Cu-CHA catalysts. In this review, the progress of NO_x control in the field of diesel engine exhaust with Cu-CHA catalysts is stated from three aspects firstly, including the influences of preparation method, the effects of reaction condition and the NH₃-SCR reaction mechanism. Then, the application of M-CHA catalysts in NH₃-SCR reaction are elaborated, where M is limited as some other transition metal and rare earth metal. Meanwhile, the advantages of bimetallic-based CHA zeolites in NH₃-SCR reaction are identified. Based on these results, the possible improvement orientations for NH₃-SCR catalysts with CHA zeolites structure are also prospected.

Contents
1 Introduction
2 Application of Cu-CHA catalysts in NH₃-SCR
2.1 Cu-SSZ-13 used for NO_x purification
2.2 Cu-SAPO-34 used for NO_x purification
3 Application of Fe-CHA catalysts in NH₃-SCR
4 Application of bimetallic active center catalysts with CHA structure in NH₃-SCR
5 Conclusion and outlook