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Modeling and flow reactor experiments are used to investigate the global kinetics for lean NO x traps (LNTs). Experiments were conducted with a Pt/Rh/BaO/Al 2 O 3 model catalyst, and the inlet feed gas was switched between lean and rich periods. It has previously been observed that NO oxidation to NO 2 is important for NO x storage, and therefore a global mechanism for NO oxidation on Pt/Al 2 O 3 is developed. This is then used in the NO x trap model, after the parameters had been adjusted to match the NO and NO 2 concentrations from experiments on the Pt/Rh/BaO/ Al 2 O 3 catalyst. The mass transport of NO and NO 2 inside the particles is described by a shrinkingcore model. Further, it is found that two global reaction steps are needed for storage in order to explain the experimental observations: one step for the formation of barium nitrates and the other step for the formation of loosely bound barium nitrites. Reaction steps were added to the model for regeneration of the trap with C 3 H 6 . The model is tuned based on six experiments at three different temperatures and two different NO concentration levels. The model is able to adequately describe NO x storage during the lean period, the NO reduction during the regeneration period, the NO x breakthrough peaks observed initially in the rich period, and the relation between the measured NO and NO 2 concentrations. Experimentally, we have observed that only a fraction of the barium is used for storage in our model catalysts. In the simulations, only 7% of the barium is used for NO x storage. In addition, TEM experiments have shown that our barium particles are large, and therefore a model is evaluated using an inert core in the center of the particle, which resulted in an equally good fit. However, when using catalysts with small particles, which probably is the case in commercial catalysts, a model without an inert core in barium particles seems to be the most realistic one. The model with an inert core is validated with three additional experiments not included in the fitting procedure. In these experiments the oxygen concentration was lowered to 4% during the lean period, compared to 8% O 2 in the experiments used when adjusting the kinetic parameters. The model can simulate the experimental features of these experiments well.

The NH 3 and H 2 O adsorption and desorption, and the NH 3 oxidation was studied using detailed kinetic modeling and flow reactor experiments. Ammonia storage and ammonia oxidation are important for the NH 3 SCR application. In this study, both ammonia storage and oxidation are investigated, with and without the presence of water. Four sites were included in the model. On each copper atom was one active site introduced, denoted S1a, where NH 3 , H 2 O, NO 2 and O 2 can adsorb. However, electron paramagnetic resonance studies (EPR) and also DFT calculations in the literature suggest that [Cu(NH 3 ) 4 ] 2+ complex are formed in copper zeolites. We therefore introduced three additional sites (S1b) that ammonia can adsorb on in order to add up to the four ammonia adsorbed per copper atom. It was important to separate between S1a and S1b since it is not possible for four NO 2 to adsorb per copper and also in order to describe the ammonia TPD and SCR reactions simultaneously. The Cu-ZSM-5 catalyst also contains Bro ¨nsted acid sites (S2), and in order to account for the large amount stored at ambient temperature, sites for weakly bound species (S3) were included as well. The Bro ¨nsted sites were investigated using NH 3 and H 2 O TPD experiments on H-ZSM-5. Water and ammonia TPD experiments on Cu-ZSM-5 were also used in the model development and the model was able to describe the experiment well. An NH 3 TPD experiment with storage performed in the presence of water was used for model validation, and the model was able to predict the experimental results adequately. The model was then extended to include steps for oxygen adsorption, desorption, dissociation, recombination and two summary steps for ammonia oxidation. Ammonia oxidation in both the presence and absence of water was used in the model development. The resulting model was able to predict ammonia storage, desorption and oxidation accurately, both in the presence and absence of water.

The power of a lithium battery depends on the mobility of the lithium ion. Since the lithium ion, Li § binds to the mobile and nonmobile molecules in the electrolyte, then the strength of the Li § binding affects the conductivity of the electrolyte. The binding of dimethyt ether, diethyl ether, acetone," ethylene carbonate, and propylene carbonate to lithium ion is calculated using ab initio quantum mechanics techniques. The binding of water and acetaldehyde to Li + has been calculated for higher coordination numbers. Using these energies, coordination numbers are predicted for all the species studied. These energetics also provide the basis for molecular simulations of cationic transport in the electrolyte.

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The selective catalytic reduction of nitrogen oxides with ammonia as the reducing agent was studied using Fourier transform infrared (FTIR) spectroscopy. The adsorbed species found on a Cu-ZSM-5 powder during exposure to NO, NO 2 or NH 3 was compared to the adsorbed species identified during SCR conditions. A blocking effect caused by ammonia at 175°C was investigated by a stepwise increase of the ammonia concentration, and the spectra indicated that the formation of nitrites or nitrates decreased as surface coverage of ammonia increased. No such effect was observed at 350°C, since the oxidation of ammonia results in very low ammonia coverage. The effect of changes in the NO to NO 2 ratio was also studied at 350°C, and the species identified during SCR reaction indicated that the enhanced activity at equimolecular amounts of NO and NO 2 possibly involves gas phase components as well as adsorbed species.