000084643 001__ 84643
000084643 005__ 20181203020412.0
000084643 0247_ $$2doi$$a10.1016/S0926-3373(98)00057-5
000084643 037__ $$aARTICLE
000084643 245__ $$aKinetics and mechanism of the reduction of NOx by H2 in oxygen - rich atmospheres on a Pt-Mo-Co / a-Al2O3 catalyst
000084643 269__ $$a1998
000084643 260__ $$c1998
000084643 336__ $$aJournal Articles
000084643 520__ $$aThe kinetics and the mechanism of the selective reduction of nitric oxides (NOx) by hydrogen is studied on a trimetallic Pt–Mo–Co/a-Al2O3 catalyst under oxidising conditions. This system is interesting in view of an exhaust gas control of power plants or lean-burn cars. It can be shown that the NO dissociation is the crucial step, dominating the overall reaction behaviour and that it depends on temperature and on the partial pressure of H2. With increasing temperatures the reaction reveals an autocatalytic behaviour resulting in bistability and hysteresis. At higher temperatures, where no bistability is found, the NO/H2 as well as the competing O2/H2 reaction occur only above a certain critical partial pressure of H2. The kinetics of the NO/H2/O2 reaction are established using a modified Langmuir–Hinshelwood model (T=142°C–160°C, yO2>4%) which takes into account the critical H2 partial pressure. The model describes the experimental data within ±15%. The determined activation energies are: 63 kJ/mol for the NOx consumption, 77 and 45 kJ/mol for the N2 and N2O formation, respectively, and 130 kJ/mol for the O2/H2 reaction. Adsorption enthalpies are determined to -59 kJ/mol for the adsorption of H2, -77 kJ/mol for the adsorption of NO and -97 kJ/mol for the adsorption of O2. An interesting feature of the reaction is the enhancement of the NO/H2 reaction by oxygen for low partial pressures of O2. This appears to be the first study where a promoting effect of oxygen for the NO/H2 reaction is found on a platinum supported catalyst.
000084643 6531_ $$aNOx
000084643 6531_ $$aHydrogen
000084643 6531_ $$aLean-burn
000084643 6531_ $$aExhaust gas
000084643 6531_ $$aKinetics
000084643 6531_ $$aMechanism
000084643 6531_ $$aPt–Mo–Co supported catalyst
000084643 700__ $$aFrank, B.
000084643 700__ $$aEmig, G.
000084643 700__ $$0240078$$aRenken, A.$$g106205
000084643 773__ $$j19$$k1$$q45-57$$tApplied Catalysis B: Environmental
000084643 8564_ $$s415534$$uhttps://infoscience.epfl.ch/record/84643/files/98_Frank_ApplCatalB.pdf$$zn/a
000084643 909C0 $$0252033$$pLGRC$$xU10178
000084643 909CO $$ooai:infoscience.tind.io:84643$$particle
000084643 937__ $$aLGRC-ARTICLE-1998-014
000084643 970__ $$aN442/LGRC
000084643 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000084643 980__ $$aARTICLE