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Title: Trends in Selective Hydrogen Peroxide Production on Transition Metal Surfaces from First Principles

Abstract

We present a comprehensive, Density Functional Theory-based analysis of the direct synthesis of hydrogen peroxide, H2O2, on twelve transition metal surfaces. We determine the full thermodynamics and selected kinetics of the reaction network on these metals, and we analyze these energetics with simple, microkinetically motivated rate theories to assess the activity and selectivity of hydrogen peroxide production on the surfaces of interest. By further exploiting Brønsted-Evans-Polanyi relationships and scaling relationships between the binding energies of different adsorbates, we express the results in the form of a two dimensional contour volcano plot, with the activity and selectivity being determined as functions of two independent descriptors, the atomic hydrogen and oxygen adsorption free energies. We identify both a region of maximum predicted catalytic activity, which is near Pt and Pd in descriptor space, and a region of selective hydrogen peroxide production, which includes Au. The optimal catalysts represent a compromise between activity and selectivity and are predicted to fall approximately between Au and Pd in descriptor space, providing a compact explanation for the experimentally known performance of Au-Pd alloys for hydrogen peroxide synthesis, and suggesting a target for future computational screening efforts to identify improved direct hydrogen peroxide synthesis catalysts. Related methodsmore » of combining activity and selectivity analysis into a single volcano plot may be applicable to, and useful for, other aqueous phase heterogeneous catalytic reactions where selectivity is a key catalytic criterion.« less

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1097962
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Catalysis, 2(12):2664−2672
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Rankin, Rees B., and Greeley, Jeffrey P. Trends in Selective Hydrogen Peroxide Production on Transition Metal Surfaces from First Principles. United States: N. p., 2012. Web. doi:10.1021/cs3003337.
Rankin, Rees B., & Greeley, Jeffrey P. Trends in Selective Hydrogen Peroxide Production on Transition Metal Surfaces from First Principles. United States. doi:10.1021/cs3003337.
Rankin, Rees B., and Greeley, Jeffrey P. Fri . "Trends in Selective Hydrogen Peroxide Production on Transition Metal Surfaces from First Principles". United States. doi:10.1021/cs3003337.
@article{osti_1097962,
title = {Trends in Selective Hydrogen Peroxide Production on Transition Metal Surfaces from First Principles},
author = {Rankin, Rees B. and Greeley, Jeffrey P.},
abstractNote = {We present a comprehensive, Density Functional Theory-based analysis of the direct synthesis of hydrogen peroxide, H2O2, on twelve transition metal surfaces. We determine the full thermodynamics and selected kinetics of the reaction network on these metals, and we analyze these energetics with simple, microkinetically motivated rate theories to assess the activity and selectivity of hydrogen peroxide production on the surfaces of interest. By further exploiting Brønsted-Evans-Polanyi relationships and scaling relationships between the binding energies of different adsorbates, we express the results in the form of a two dimensional contour volcano plot, with the activity and selectivity being determined as functions of two independent descriptors, the atomic hydrogen and oxygen adsorption free energies. We identify both a region of maximum predicted catalytic activity, which is near Pt and Pd in descriptor space, and a region of selective hydrogen peroxide production, which includes Au. The optimal catalysts represent a compromise between activity and selectivity and are predicted to fall approximately between Au and Pd in descriptor space, providing a compact explanation for the experimentally known performance of Au-Pd alloys for hydrogen peroxide synthesis, and suggesting a target for future computational screening efforts to identify improved direct hydrogen peroxide synthesis catalysts. Related methods of combining activity and selectivity analysis into a single volcano plot may be applicable to, and useful for, other aqueous phase heterogeneous catalytic reactions where selectivity is a key catalytic criterion.},
doi = {10.1021/cs3003337},
journal = {ACS Catalysis, 2(12):2664−2672},
number = ,
volume = ,
place = {United States},
year = {Fri Oct 19 00:00:00 EDT 2012},
month = {Fri Oct 19 00:00:00 EDT 2012}
}
  • In this paper the first-principles generalized pseudopotential theory (GPT) of transition-metal interatomic potentials [J. A. Moriarty, Phys. Rev. B {bold 38}, 3199 (1988)] is extended to AB binary compounds and alloys. For general transition-metal (TM) systems, the GPT total-energy functional involves a volume term, central-force pair potentials, and angular-force multi-ion potentials, which are both volume ({Omega}) and concentration (x) dependent and include all sp, sp-d, and d-d interactions within local density-functional quantum mechanics. The formalism is developed here in detail for intermetallic systems where A is a simple metal and B is a transition metal and applied to the prominentmore » special case of the transition-metal aluminides TM{sub x}Al{sub 1{minus}x}, where sp-d hybridization is especially important. Emphasis is given to the aluminum-rich 3d binary systems for x{lt}0.30, which appear to be well described at the pair-potential level without angular forces and for which the present GPT potentials can be used directly in atomistic simulations. Volume terms and pair potentials for all of the 3d aluminides have been calculated and their behavior with atomic number, {Omega}, and x is elaborated through illustrative applications to the cohesive and structural trends across the 3d series. More extensive applications to the Co-Al and Ni-Al phase diagrams will be given elsewhere. {copyright} {ital 1997} {ital The American Physical Society}« less
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  • The first-principles generalized pseudopotential theory of bulk transition-metal interatomic potentials is extended to surfaces by transforming the total-energy functional to a local-environment representation in which both the volume term and the multiion potentials are modulated by local averages of the electron density or the density of states. The theory encompasses and goes beyond simple embedded-atom schemes by including the angular forces necessary to treat the central bcc metals. Applications to the vacancy-formation and free-surface energetics of Cu and Mo are discussed.
  • Some salient features of the experimental and theoretical data pertaining to hydrogen negative ion generation on minimum-work-function composite surfaces consisting of Cs/transition metal substrates are reviewed. Cesium or hydrogen ion bombardment of a cesium-activated negatively-biased electrode exposed to a cesium-hydrogen discharge results in the release of hydrogen negative ions. These ions originate through desorption of hydrogen particles by incident cesium ions, desorption by incident hydrogen ions, and by backscattering of incident hydrogen. Each process is characterized by a specific energy and angular distribution. The calculation of ion formation in the crystal selvage region is discussed for different approximations to themore » surface potential. Results of ab initio, all-electron, local density function calculations for the composite surface electronics of Cs on W(001) and Mo(001) are presented and discussed.« less