Microkinetic Simulation of Ammonia Oxidation on the RuO₂(110) Surface

Abstract

The investigation by microkinetic simulations provide detailed reaction mechanisms about the NH 3 oxidation on the RuO 2 (110) surface. There are 41 elementary reactions involved in the microkinetic model in which all the thermodynamic and kinetic parameters are obtained from density functional theory (DFT) calculations, and the entropy effects of each reaction are considered in the simulation. The differences in reaction mechanisms between the batch type and the steady state were characterized in this study. The selectivities to the oxidation products, including N 2 , NO, and N 2 O, depend on the oxidation conditions. The simulated results show that the O 2 /NH 3 ratio, system temperature, and pressure are the controlling factors that could alter the results of the oxidation. The microkinetic modeling demonstrates how these parameters affect the NH 3 conversion and the selectivities. The simulations showed that N 2 and NO could be a primary product under different oxidizing conditions; however, N 2 O could only be a minor product because of the nature of its formation mechanism. The highest N 2 O selectivity obtained in the simulations is 30%.

NO dissociation and reduction by H 2 on Pd(1 1 1): A first-principles study

“…It should be noted that the rate constant of bond breaking increases while the coverages of adsorbates decreases with increasing temperature; the increase of the former is not fast enough to compensate for the decrease of the coverages of intermediates at high temperature, and consequently, a maximum conversion rate reaches at an optimum temperature range. Similar cases can also be found for some other catalytic reactions on metal surfaces [54][55][56]. Our result agrees with the experimental observation that N 2 reaches its maximum formation rate at around 600 K and NH 3 and H 2 O reach their maximum formation rates at around 530 K [22].…”

Selective Oxidation of Ammonia by Co-adsorbed Oxygen on Iridium Surfaces: Formation of N2O

“…Selective catalytic oxidation of ammonia is one of the most important heterogeneous catalytic processes [1], which has received increasing interest [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The reaction proceeds through the three competing pathways to yield N-containing products of N 2 , NO and N 2 O.…”

Boosting RuO2 Surface Reactivity by Cu Active Sites over Ru/Cu-SSZ-13 for Simultaneous Catalytic Oxidation of CO and NH3

“…RuO 2 was confirmed as a catalytic driver for oxidizing CO and NH 3 at relatively low temperatures in these composite zeolite materials, as shown in Figure . Table S2 lists the corresponding energetics of the elementary reaction of CO and NH 3 oxidation on a RuO 2 (110) surface reported in the previous studies. ,− The stoichiometric (110) surface of rutile RuO 2 is the source of catalytic activity, exposing the twofold coordinated oxygen atom and fivefold coordinated Ru atom (Scheme a). , These unsaturated-coordination Ru sites (denoted as Ru cus ) provide numerous dangling bonds and are highly sensitive to NH 3 , CO, and O 2 molecules (P1–P3), in which NH 3 presents the largest adsorption energy (Table S2). Herein, we labeled NH 3 , CO, and O 2 adsorbed at Ru cus sites as NH 3‑cus , CO cus , and O 2‑cus .…”