Spatiotemporal distribution of NOx storage and impact on NH3 and N2O selectivities during lean/rich cycling of a Ba-based lean NOx trap catalyst

Study of N2O Formation over Rh- and Pt-Based LNT Catalysts

“…It has been suggested that N 2 O formation at the lean to rich transition occurs at the regeneration front, upon reduction of the stored NO x over not fully reduced Platinum-Group-Metal (PGM) sites. On the other hand, N 2 O formation upon the rich to lean transition originates from reaction between residual surface NO x with reductive species (like NCO, CO or NH 3 ) in an adsorbed state [3,4,7]. This N 2 O peak can be reduced if a neutral or slightly lean phase is inserted between the rich and the lean phase, since a more complete regeneration of the catalyst can be attained [9].…”

“…At variance, N 2 O is a highly undesired by-product in view of its very high global warming potential (nearly 300 times that of CO 2 ). Over fully formulated catalysts, it has been shown that N 2 O formation is apparent both upon switch from lean to rich mode but also during the alternation from rich to lean regime [3][4][5][6][7][8]. It has been suggested that N 2 O formation at the lean to rich transition occurs at the regeneration front, upon reduction of the stored NO x over not fully reduced Platinum-Group-Metal (PGM) sites.…”

Improved Kinetic Data Acquisition Using An Optically Accessible Catalytic Plate Reactor with Spatially-Resolved Measurement Techniques. Case of Study: CO2 Methanation

“…Thereafter, H 2 and CO 2 decreased from 67 to 59 mol% and from 13 to 9.3 mol%, respectively towards the end of the plate. While CH 4 and H 2 O increased to 2.9 and 7.8 mol%, respectively. Besides CH 4 , a considerable amount of CO was formed (2.2 mol% at the end of the plate).…”

“…While CH 4 and H 2 O increased to 2.9 and 7.8 mol%, respectively. Besides CH 4 , a considerable amount of CO was formed (2.2 mol% at the end of the plate). The increase in the CO concentration can be explained due to the reversed water gas shift (CO 2 + H 2 Ø CO + H 2 O), which also lead to an increase in the H 2 O content.…”

“…For example, direct sampling of the gas phase and temperature along the reactor axis can be achieved using a movable capillary and thermocouple or pyrometers, respectively, or via multiple fixed probing. These techniques have been applied in different reactor configurations such as monolith [3][4][5], coated metal foam [6][7][8], fixed bed [9] and fluidized bed [1]. The main disadvantage of the aforementioned setups is the unknown catalyst mass distribution along the reactor axis between the sampling points, thus they are not suitable for kinetic data collection.…”