Theoretical Investigation of Ammonia Thermal Desorption and Oxidation on RuO2(110): A Combined DFT and Microkinetic Study

• Main Authors: Jyun-Yi Wu, 吳軍毅
• Other Authors: Jyh-chiang Jiang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/56552240794286027746

碩士 === 國立臺灣科技大學 === 化學工程系 === 99 === We combined the DFT calculations and microkinetic modeling to simulate the TDS spectra of NH3, O2, and H2O and predict the formation rates of ammonia oxidation products including N2, NO, and N2O with various conditions on the RuO2(110) surface. In the TDS simulation, we considered several coverages of all the three adsorbents to calculate the desorption rate which is function of temperature. Especially, we examined the role of pre-exponential factors which were determined with statistic thermodynamic treatment or were set as convention assumption of 1013 s-1. In the study of ammonia oxidation, our reaction model contained 19 elementary reaction steps including adsorption, surface reaction, and desorption. The adsorption/desorption rate constants were treated with collision theory, and others were treated with transition state theory. The pre-exponential factors are also determined with the statistic thermodynamic treatment in this part. Considered O2/NH3 ratio, temperature, coverage effects, our microkinetic analysis indicated that RuO2(110) exhibits very good catalytic activity and selectivity to N-containing products for ammonia oxidation. The calculations are in good agreement with available experiments.