| Summary: | The behavior and operation parameters were analyzed for the hybrid LNT-SCR (Lean NO<sub>x</sub>-Trap−Selective Catalytic Reduction) system with advanced catalyst formulations. Pt-Ba-K/Al<sub>2</sub>O<sub>3</sub> was used as an NSR (NO<sub>x</sub> Storage and Reduction) or LNT catalyst effective in NO<sub>x</sub> and soot simultaneous removal whereas Cu-SAPO-34 with 2 wt.% of copper inside the structure was the small pore zeolite employed as the SCR catalyst. Under alternating and cyclic wet conditions, feeding volumetric concentrations of 1000 ppm of NO, 3% of O<sub>2</sub>, 1.5% of water, 0.3% of CO<sub>2</sub>, and H<sub>2</sub> as a reductant, the NO<sub>x</sub>-conversion values were above 95% and a complete mineralization to nitrogen was registered using θ ≤ 3 (20 s of regeneration) and a hydrogen content between 10,000 and 2000 ppm in the whole temperature range tested. An excess of hydrogen fed (above 1% v/v) during the rich phase is unnecessary. In addition, in the low temperature range below 250 °C, the effect is more noticeable due to the further ammonia production and its possible slip. These results open the way to the scale up of the coupled catalytic technologies for its use in real conditions while controlling the influence of the operation map.
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