Rh/CeO2+Pt/Ba/Mn/Al2O3 model NSR catalysts: Effect of Rh/Pt weight ratio

Electrification-Enhanced Low-Temperature NOx Storage–Reduction on Pt and K Co-Supported Antimony-Doped Tin Oxides

“…Storage and reduction of NO x (NSR), also known as lean NO x traps (LNT), are currently employed for controlling NO x emission from light-duty diesel vehicles, − which periodically injects fuels into the exhaust, resulting in alternating fuel-lean and fuel-rich conditions. In the lean conditions, NO is oxidized to NO 2 and stored on NSR catalysts as nitrites/nitrates, while in the rich condition, the stored NO x species are desorbed and reduced to N 2 by the injected fuels, such as H 2 , CO, and C 3 H 6 . − A typical NSR catalyst is primarily composed of active components for NO oxidation and NO x reduction (noble metals such as Pt, Pd, and Rh), adsorption components for NO x storage (alkali/alkaline earth metals such as K and Ba, and perovskites), and supports with large specific surface areas (for instance, Al 2 O 3 , Mg–Al mixed oxides, and zeolites , ). Conventional NSR catalysts like Pt-BaO/Al 2 O 3 display high activity for NO x removal above 300 °C .…”

Comparison of Cu-CHA-Zeolites in the Hybrid NSR-SCR Catalytic System for NOx Abatement in Mobile Sources

“…NSR systems consist of lean NO x trap (LNT) catalysts conformed by a high surface area supporting material (γ-Al 2 O 3 ), an oxidation element (Pt, Pd or Rh) and NO x -storage components, such as alkaline or alkaline-earth metal oxides (Ba, K). This technology performs in two-cycled fed conditions, fuel-lean, which involves the oxidation of NO to NO 2 that is catalyzed by the noble metal and its storage as nitrate and nitrites on LNT components; then, during the subsequently short fuel-rich period, the stored nitrates and nitrites are reduced to the desired product N 2 and the undesired products N 2 O and NH 3 -slip [5][6][7][8]. Meanwhile, SCR utilizes NH 3 (injected into the exhaust stream from an aqueous urea tank, AdBlue ® Technology) as the NO x reductant, usually on a Cu-and/or Fe-exchanged zeolite-type catalyst, that leads to N 2 and H 2 O through the well-described SCR reactions [9][10][11][12][13][14].…”