The Challenges and Comprehensive Evolution of Cu-Based Zeolite Catalysts for SCR Systems in Diesel Vehicles: A Review

Nitrogen oxides (NO x ) are major contaminant causing environmental pollution in atmosphere. The most effective method for NO x removal is ammonia selective catalytic reduction (NH 3 -SCR), and catalysts play a crucial role. Cu-based zeolite catalysts are commonly used for the removal of NO x from diesel engine exhaust, but the complex composition of diesel exhaust and the harsh operating environment of catalysts make zeolite catalysts susceptible to deactivation, thus limiting their practical application. This manuscript focuses on the negative effects of actual working conditions associated with diesel vehicle exhausts and analyses the influence of composition structure that Cu-based zeolite catalysts have on NH 3 -SCR reaction, which refers mainly to the effects brought by topology, Si/Al ratio and Cu species. The strategies for developing Cu-based zeolite catalysts are summarized, and the current development bottlenecks such as improving catalytic performance, reducing synthesis cost and enhancing production efficiency are discussed, and the future research directions of Cu-based zeolite are prospected.