Catalytic Reaction Mechanism of NO–CO on the ZrO2 (110) and (111) Surfaces

Abstract

Due to the large population of vehicles, significant amounts of carbon monoxide (CO), nitrogen oxides (NOx), and unburned hydrocarbons (HC) are emitted into the atmosphere, causing serious pollution to the environment. The use of catalysis prevents the exhaust from entering the atmosphere. To better understand the catalytic mechanism, it is necessary to establish a detailed chemical reaction mechanism. In this study, the adsorption behaviors of CO and NO, the reaction of NO reduction with CO on the ZrO2 (110) and (111) surfaces was performed through periodic density functional theory (DFT) calculations. The detailed mechanism for CO2 and N2 formation mainly involved two intermediates N2O complexes and NCO species. Moreover, the existence of oxygen vacancies was crucial for NO reduction reactions. From the calculated energy, it was found that the pathway involving NCO intermediate interaction occurring on the ZrO2 (110) surface was most favorable. Gas phase N2O formation and dissociation were also considered in this study. The results indicated the role of reaction intermediates NCO and N2O in catalytic reactions, which could solve the key scientific problems and disputes existing in the current experiments.

The Physical Chemistry and Chemical Physics (PCCP) Section of the International Journal of Molecular Sciences in Its Publications: The First 300 Thematic Articles in the First 3 Years

“…This direction is represented by 39 articles [ 28 , 35 , 129 , 134 , 136 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 , 207 , 208 , 209 , 210 , 211 , 212 , 213 , 214 , 215 , 216 , 217 , 218 , 219 , 220 , 221 , 222 , 223 ]. Their distribution, according to the above types, is presented in Table 7 .…”

“…In this research, the given reaction between cyclopentadiene and methyl acrylate was computationally investigated in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM] [PF 6 ], as a basis for the validation of the OPLS-VSIL to properly reproduce a reaction medium environment. The articles of group ( c ) include publications [ 28 , 129 , 136 , 193 , 195 , 199 , 200 , 202 , 208 , 209 , 212 , 213 , 215 , 220 ]: in most of them [ 129 , 136 , 195 , 199 , 200 , 202 , 208 , 209 , 212 , 215 ], the objects of quantum chemical calculations were the chelate and macrocyclic coordination compounds of various s -, p -, d -, and f -elements. The most significant of them seems to be publication [ 136 ], devoted to Pu(IV) and Pu(VI) complexes with tridentate (NNN)-donor-atomic ligands, in particular, di(pyridyl-2)amine, 1,3-diamino-2-azapropane, and 2,6-di(pyridyl-2) pyridine, the results of which can be very useful in the development of new extractants and organic sensors of plutonium.…”

“…In [ 129 , 213 ], quantum–chemical methods used for calculating DFT OPBE/TZVP and DFT B3PW91/TZVP were used to substantiate the fundamental possibility of the existence of complexes of iron, cobalt, and nickel with porphyrazine, its derivatives, and oxo ligands in oxidation state VI that is unusual for these elements. Inorganic compounds that are not coordination compounds were considered only in [ 28 , 193 , 215 , 220 ]. It should be noted that the only review in this thematic area is [ 220 ], devoted specifically to the quantum–chemical calculations of chemical compounds, namely, the structures of higher fullerenes, in which, among other things, a formalization of the substructure approach to assessing the stability of higher fullerenes is proposed, which is based on a detailed analysis of the main structural features of fullerene molecules.…”

“…It should be noted that the only review in this thematic area is [ 220 ], devoted specifically to the quantum–chemical calculations of chemical compounds, namely, the structures of higher fullerenes, in which, among other things, a formalization of the substructure approach to assessing the stability of higher fullerenes is proposed, which is based on a detailed analysis of the main structural features of fullerene molecules. Furthermore, article [ 193 ] is noteworthy, which considered the adsorption behaviors of CO and NO, and the reaction of NO reduction with CO on the ZrO 2 (110) and (111) surfaces was performed through periodic density functional theory (DFT) calculations. It is interesting to note that namely, in this group of articles, 2 articles out of 5 of the Editorial type [ 199 , 215 ] are presented, which are included in the general list of 300 articles considered by us in the given our review.…”

Surface reduction properties of ceria–zirconia solid solutions: a first-principles study

“…From the adsorption behaviors of CO on the Ce 0.875 Zr 0.125 O 2 (110) surface, we found that Zr T was the most favorable active site owing to the maximum adsorption energy. Besides, according to the adsorption energies of CO on the CeO 2 (110) surface (E ads z À0.2 eV)34,35 and ZrO 2 (110) surface (E ads z À0.6 eV),40 it also could be concluded that CO preferred to interact with Zr atoms and adsorb on the top site of Zr on Ce 1Àx Zr x O 2 (110) surfaces. However, it is noteworthy that CO adsorption on Ce 1Àx Zr x O 2 (110) surfaces were still rather weak (E ads z À0.6 eV), indicating that the feasible CO oxidation mechanism was gas-phase CO molecule directly extracting…”