Research progress on selective catalytic reduction of NOx by NH3 over copper zeolite catalysts at low temperature: reaction mechanism and catalyst deactivation

Hard Template-Assisted Trans-Crystallization Synthesis of Hierarchically Porous Cu-SSZ-13 with Enhanced NH3-SCR Performance

“…To comply with current and future emission regulations, it is urgent and imperative to eliminate NO x emissions from diesel engines. Among the various NO x removal technologies, the selective catalytic reduction of NO x with ammonia (NH 3 -SCR) is regarded as the most efficient method [4,5], and copper (Cu)-exchanged SSZ-13 zeolites are now commercial products for NH 3 -SCR catalysts due to their outperformance in reducing diesel engine NO x emissions compared with traditional vanadia-based (V 2 O 5 -WO 3 /TiO 2 ) catalysts [6][7][8][9][10]. However, the SSZ-13 zeolite has a chabazite (CHA) structure with a relatively small pore radius of 3.8 Å in an eight-membered ring, which may limit the mass transfer of reactants in channels [11,12].…”

Electric field-assisted NSR process for lean NOx reduction at low temperatures

“…Typical NSR catalysts combine noble metals (Pt, Pd, Rh) as active sites and alkali or alkaline earth metal oxides (Ba, K) as NO x storage sites. [4][5][6] Conventional NSR catalysts work under cycling conditions. Under lean burn conditions, NO is oxidized by O 2 and is stored on the NSR catalyst surface in the form of nitrate (NO 3 À ).…”