Comparison Between a Pt–Rh/Ba/Al₂O₃and a Newly Formulated NO_X-Trap Catalysts Under Alternate Lean–Rich Flows

DRIFTS-MS-SSITKA Study of the Reverse Water-Gas Shift Reaction

“…Operando and in situ investigations of heterogeneous catalytic reactions are receiving increasing attention, allowing the simultaneous collection of spectroscopic and kinetic data under conditions relevant to actual catalytic processes [1][2][3][4][5][6][7] A number of techniques are nowadays routinely combined, yet it is surprising that the simultaneous utilisation of steadystate isotopic transient kinetic analysis (SSITKA) and spectroscopy is still rare. Tamaru and co-workers were the first to report on the combined utilisation of spectroscopic data during SSITKA analysis (so-called isotopic "jump" method) [8].…”

Effect of Pt and Ba content on NO x Storage and Reduction Over Pt/Ba/Al2O3

“…The stored amount of nitrates was estimated from the integration of the bands in the range of 1650-1250 cm -1 using extinction coefficient of 16.04 cm/lmol in the similar manner reported previously [29]. 1420, and 1540 cm -1 , which are assignable to bidentate (1320 and 1540 cm -1 ) and ionic (1420 cm -1 ) nitrates, respectively [19,23,[29][30][31][32][33][34]. In the initial stage of adsorption (150 s), a weak band assignable to nitrite was also observed around at 1200 cm -1 .…”

“…It is well investigated that O 2 also plays important role in the oxidation step after the adsorption of NO x , i.e., conversion of nitrite to nitrate [29][30][31][32][33][34][35][36][37]. Forzatti et al proposed that storage of nitrate starts from oxidation of NO to gaseous NO 2 and then proceeds two parallel routes; (1) NO 2 disproportion on Ba sites with evolution of gaseous NO, and (2) direct storage of NO 2 as nitrites followed by oxidation to nitrates [37].…”

Hydrotalcite as a Support for NOx Trap Catalyst

“…However, conventional three-way catalysts hardly reduce NOx emission from both engines operated under lean conditions [1,2]. A promising approach for overcoming this drawback may be the development of NOx storage-reduction (NSR) catalyst, in which NOx is trapped on alkaline and/or alkaline-earth metals (Ba, K or Li) under lean conditions and is reduced to N 2 over noble metals (Pt, Rh or Pd) under rich conditions [3][4][5][6][7][8][9][10][11]. Over the past decade, Al 2 O 3 has been considered to be the best and the most common support for NSR catalyst, mainly due to its stability and accessibility.…”