skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Density Functional Theory Calculations and Analysis of Reaction Pathways for Reduction of Nitric Oxide by Hydrogen on Pt(111)

Abstract

Reaction pathways are explored for low temperature (e.g., 400 K) reduction of nitric oxide by hydrogen on Pt(111). First-principles electronic structure calculations based on periodic, self-consistent density functional theory(DFT-GGA, PW91) are employed to obtain thermodynamic and kinetic parameters for proposed reaction schemes on Pt(111). The surface of Pt(111) during NO reduction by H₂ at low temperatures is predicted to operate at a high NO coverage, and this environment is explicitly taken into account in the DFT calculations. Maximum rate analyses are performed to assess the most likely reaction mechanisms leading to formation of N₂O, the major product observed experimentally at low temperatures. The results of these analyses suggest that the reaction most likely proceeds via the addition of at least two H atoms to adsorbed NO, followed by cleavage of the N-O bond.

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1222115
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Catalysis, 4(10):3307–3319
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Farberow, Carrie A., Dumesic, James A., and Mavrikakis, Manos. Density Functional Theory Calculations and Analysis of Reaction Pathways for Reduction of Nitric Oxide by Hydrogen on Pt(111). United States: N. p., 2014. Web. doi:10.1021/cs500668k.
Farberow, Carrie A., Dumesic, James A., & Mavrikakis, Manos. Density Functional Theory Calculations and Analysis of Reaction Pathways for Reduction of Nitric Oxide by Hydrogen on Pt(111). United States. doi:10.1021/cs500668k.
Farberow, Carrie A., Dumesic, James A., and Mavrikakis, Manos. Fri . "Density Functional Theory Calculations and Analysis of Reaction Pathways for Reduction of Nitric Oxide by Hydrogen on Pt(111)". United States. doi:10.1021/cs500668k.
@article{osti_1222115,
title = {Density Functional Theory Calculations and Analysis of Reaction Pathways for Reduction of Nitric Oxide by Hydrogen on Pt(111)},
author = {Farberow, Carrie A. and Dumesic, James A. and Mavrikakis, Manos},
abstractNote = {Reaction pathways are explored for low temperature (e.g., 400 K) reduction of nitric oxide by hydrogen on Pt(111). First-principles electronic structure calculations based on periodic, self-consistent density functional theory(DFT-GGA, PW91) are employed to obtain thermodynamic and kinetic parameters for proposed reaction schemes on Pt(111). The surface of Pt(111) during NO reduction by H₂ at low temperatures is predicted to operate at a high NO coverage, and this environment is explicitly taken into account in the DFT calculations. Maximum rate analyses are performed to assess the most likely reaction mechanisms leading to formation of N₂O, the major product observed experimentally at low temperatures. The results of these analyses suggest that the reaction most likely proceeds via the addition of at least two H atoms to adsorbed NO, followed by cleavage of the N-O bond.},
doi = {10.1021/cs500668k},
journal = {ACS Catalysis, 4(10):3307–3319},
number = ,
volume = ,
place = {United States},
year = {Fri Oct 03 00:00:00 EDT 2014},
month = {Fri Oct 03 00:00:00 EDT 2014}
}
  • Cited by 14
  • Periodic, self-consistent density functional theory (DFT-GGA, PW91) calculations are used to study the reaction mechanism for nitric oxide (NO) reduction by hydrogen (H 2) on Pt(100). Energetics of various N–O activation paths, including both direct and hydrogen-assisted N–O bond-breaking paths, and the formation of three different N-containing products (N 2, N 2O, and NH3), are systematically studied. On the basis of our analysis, NO* dissociation has a lower barrier than NO* hydrogenation to HNO* or NOH*, and therefore, the direct NO dissociation path is predicted to dominate N–O activation on clean Pt(100). The reaction of atomic N* with N* andmore » NO* is proposed as the mechanism for N 2 and N 2O formation, respectively. NH 3 formation from N* via three successive hydrogenation steps is also studied and is found to be kinetically more difficult than N 2 and N 2O formation from N*. Finally, NO adsorption phase diagrams on Pt(100) are constructed, and these phase diagrams suggest that, at low temperatures (e.g., 400 K), the Pt(100) surface may be covered by half a monolayer of NO. We propose that high NO coverage might affect the NO + H 2 reaction mechanism, and therefore, one should explicitly take the NO coverage into consideration in first-principles studies to determine the reaction mechanism on catalyst surfaces under reaction conditions. In conclusion, a detailed analysis of high NO coverage effects on the reaction mechanism will be presented in a separate contribution.« less
  • Glycerol decomposition on Pt(111) via dehydrogenation or C–C bond scission is examined with periodic density functional theory (DFT) calculations. The thermochemistry of dehydrogenation intermediates is first estimated using an empirical correlation scheme with parameters fit to selected DFT calculations; the resulting estimates for the more stable intermediates are refined with full DFT calculations. Brønsted–Evans–Polanyi (BEP) relationships for dehydrogenation and C–C bond scission reactions are developed and used to estimate the kinetics of elementary dehydrogenation and C–C bond scission steps in the reaction network. The combined thermochemical and kinetic analysis implies that glycerol dehydrogenation products at intermediate levels of dehydrogenation aremore » the most thermochemically stable. Additionally, although C–C bond scission transition state energies are high for glycerol and for intermediates at early stages of dehydrogenation, these energies decrease as the intermediates are successively dehydrogenated, reaching a minimum after the removal of several hydrogen atoms from glycerol. At these levels of dehydrogenation, the C–C scission transition state energies become comparable to those of O–H or C–H scission. These results suggest that C–C bonds are only broken after glycerol has been significantly dehydrogenated and demonstrate that DFT-based analyses, combined with simple correlation schemes, can be effective for elucidating general features of complex biomassic reaction networks.« less