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Title: Effect of nanoscale flows on the surface structure of nanoporous catalysts

Here, the surface structure and composition of a multi-component catalyst are critical factors in determining its catalytic performance. The surface composition can depend on the local pressure of the reacting species, leading to the possibility that the flow through a nanoporous catalyst can affect its structure and reactivity. Here, we explore this possibility for oxidation reactions on nanoporous gold, an AgAu bimetallic catalyst. We use microscopy and digital reconstruction to obtain the morphology of a two-dimensional slice of a nanoporous gold sample. Using lattice Boltzmann fluid dynamics simulations along with thermodynamic models based on first-principles total-energy calculations, we show that some sections of this sample have low local O 2 partial pressures when exposed to reaction conditions, which leads to a pure Au surface in these regions, instead of the active bimetallic AgAu phase. We also explore the effect of temperature on the surface structure and find that moderate temperatures (≈300–450 K) should result in the highest intrinsic catalytic performance, in apparent agreement with experimental results.
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [1] ; ORCiD logo [4] ;  [5] ;  [1]
  1. Harvard Univ., Cambridge, MA (United States)
  2. Univ. of Rome “Roma Tre,” Rome (Italy)
  3. Harvard Univ., Cambridge, MA (United States); Istituto per le Applicazioni del Calcolo - CNR, Rome (Italy)
  4. Harvard Univ., Cambridge, MA (United States); Univ. of Rome "Tor Vergata", Rome (Italy)
  5. Harvard Univ., Cambridge, MA (United States); Center for Nanoscale Systems, Cambridge, MA (United States)
Publication Date:
Grant/Contract Number:
SC0012573
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 146; Journal Issue: 21; Related Information: IMASC partners with Harvard University (lead); Fritz Haber Institute; Lawrence Berkeley National Laboratory; Lawrence Livermore National Laboratory; University of Kansas; Tufts University; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Energy Frontier Research Centers (EFRC), Washington, D.C. (United States). Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (heterogeneous); mesostructured materials; materials and chemistry by design; synthesis (novel materials)
OSTI Identifier:
1388894
Alternate Identifier(s):
OSTI ID: 1365429

Montemore, Matthew M., Montessori, Andrea, Succi, Sauro, Barroo, Cédric, Falcucci, Giacomo, Bell, David C., and Kaxiras, Efthimios. Effect of nanoscale flows on the surface structure of nanoporous catalysts. United States: N. p., Web. doi:10.1063/1.4984614.
Montemore, Matthew M., Montessori, Andrea, Succi, Sauro, Barroo, Cédric, Falcucci, Giacomo, Bell, David C., & Kaxiras, Efthimios. Effect of nanoscale flows on the surface structure of nanoporous catalysts. United States. doi:10.1063/1.4984614.
Montemore, Matthew M., Montessori, Andrea, Succi, Sauro, Barroo, Cédric, Falcucci, Giacomo, Bell, David C., and Kaxiras, Efthimios. 2017. "Effect of nanoscale flows on the surface structure of nanoporous catalysts". United States. doi:10.1063/1.4984614. https://www.osti.gov/servlets/purl/1388894.
@article{osti_1388894,
title = {Effect of nanoscale flows on the surface structure of nanoporous catalysts},
author = {Montemore, Matthew M. and Montessori, Andrea and Succi, Sauro and Barroo, Cédric and Falcucci, Giacomo and Bell, David C. and Kaxiras, Efthimios},
abstractNote = {Here, the surface structure and composition of a multi-component catalyst are critical factors in determining its catalytic performance. The surface composition can depend on the local pressure of the reacting species, leading to the possibility that the flow through a nanoporous catalyst can affect its structure and reactivity. Here, we explore this possibility for oxidation reactions on nanoporous gold, an AgAu bimetallic catalyst. We use microscopy and digital reconstruction to obtain the morphology of a two-dimensional slice of a nanoporous gold sample. Using lattice Boltzmann fluid dynamics simulations along with thermodynamic models based on first-principles total-energy calculations, we show that some sections of this sample have low local O2 partial pressures when exposed to reaction conditions, which leads to a pure Au surface in these regions, instead of the active bimetallic AgAu phase. We also explore the effect of temperature on the surface structure and find that moderate temperatures (≈300–450 K) should result in the highest intrinsic catalytic performance, in apparent agreement with experimental results.},
doi = {10.1063/1.4984614},
journal = {Journal of Chemical Physics},
number = 21,
volume = 146,
place = {United States},
year = {2017},
month = {6}
}