adsorbed ammonia
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In the presented paper the effect of ammonia vapors on the electrical properties of nanosized tin dioxide films obtained using polymers was investigated to assess the possibility of their use as an ammonia sensor’s sensitive element at room temperature. Ammonia vapor leads to a decrease in the conductivity of the studied SnO2 films. This is due to the fact that the adsorbed ammonia molecules increase the height of the intergranular potential barriers, and the surface shut-off bend of the energy bands. The main role in this is played by the processes of physical adsorption of ammonia molecules. The sensitivity of the films to ammonia vapor is in the range of 0.35-0.63 and reaches a maximum at a voltage of 300 V. The processes of adsorption and desorption take place in two stages and are reversible, as evidenced by the calculated time constants of adsorption and desorption.

DFT calculations highlight the role of co-adsorbed ammonia in catalytic activity in the amination of alcohols by ammonia.

The atomic positions and interactions between adsorbed guest molecules, such as ammonia in H-ZSM-5 microporous solids, are for the first time revealed by using in situ synchrotron powder X-ray diffraction combined with refinement within experimental errors.

In this work, the adsorption and reaction performance of various adsorbed ammonia species during the passive-SCR process were investigated.

IR spectroscopy and quantum chemical modeling (supplemented by the analysis of charge transfer channels between co-adsorbed ammonia and Co(ii)–NO adduct) show that donor NH3 co-ligands to cobalt cationic centers in zeolites strongly activate the N−O bond.

In this paper, the model of SCR after-treatment system is established by the software MATLAB and the control strategy for the system is studied also. Based on Eley-rideal mechanism, four major chemical reactions including the adsorption of ammonia, desorption of ammonia, selective catalytic reduction and oxidation of adsorbed ammonia are selected to study the SCR control strategy. Based on the energy conservation law, the equation calculating the temperature of the layered model is derived. Combined with the equations of chemical reaction process, a mathematical model of SCR catalytic converter is established. To achieve a high NOXreduction efficiency of SCR system, the reasonable and efficacious control strategies for the micro-element models of SCR catalytic is simulated, which including the feedback control strategy based on the feed-forward controller and the PID control strategy.