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Title: Partial and complete reduction of O2 by hydrogen on transition metal surfaces

Abstract

The metal-catalyzed reduction of di-oxygen (O{sub 2}) by hydrogen is at the heart of direct synthesis of hydrogen peroxide (HOOH) and power generation by proton exchange membrane fuel cells. Despite its apparent simplicity, how the reaction proceeds on different metals is not yet well understood. We present a systematic study of O{sub 2} reduction on the (111) facets of eight transition metals (Rh, Ir, Ni, Pd, Pt, Cu, Ag, and Au) based on periodic density functional theory (DFT-GGA) calculations. Analysis of ten surface elementary reaction steps suggests three selectivity regimes as a function of the binding energy of atomic oxygen (BEO), delineated by the opposite demands to catalyze O-O bond scission and O-H bond formation: The dissociative adsorption of O{sub 2} prevails on Ni, Rh, Ir, and Cu; the complete reduction to water via associative (peroxyl, peroxide, and aquoxyl) mechanisms prevails on Pd, Pt, and Ag; and HOOH formation prevails on Au. The reducing power of hydrogen is decreased electrochemically by increasing the electrode potential. This hinders the hydrogenation of oxygen species and shifts the optimal selectivity for water to less reactive metals. Our results point to the important role of the intrinsic reactivity of metals in the selectivity ofmore » O{sub 2} reduction, provide a unified basis for understanding the metal-catalyzed reduction of O{sub 2} to H{sub 2}O and HOOH, and offer useful insights for identifying new catalysts for desired oxygen reduction products.« less

Authors:
 [1];  [1];  [2];  [1]
  1. University of Wisconsin, Madison
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
985769
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Surface Science
Additional Journal Information:
Journal Volume: 604; Journal Issue: 19-20; Journal ID: ISSN 0039-6028
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 30 DIRECT ENERGY CONVERSION; ADSORPTION; BINDING ENERGY; CATALYSTS; ELECTRODES; FUNCTIONALS; HYDROGEN; HYDROGEN PEROXIDE; HYDROGENATION; OXYGEN; POWER GENERATION; PROTON EXCHANGE MEMBRANE FUEL CELLS; SYNTHESIS; TRANSITION ELEMENTS; WATER

Citation Formats

Ford, Denise, Nilekar, Anand Udaykumar, Xu, Ye, and Mavrikakis, Manos. Partial and complete reduction of O2 by hydrogen on transition metal surfaces. United States: N. p., 2010. Web. doi:10.1016/j.susc.2010.05.026.
Ford, Denise, Nilekar, Anand Udaykumar, Xu, Ye, & Mavrikakis, Manos. Partial and complete reduction of O2 by hydrogen on transition metal surfaces. United States. https://doi.org/10.1016/j.susc.2010.05.026
Ford, Denise, Nilekar, Anand Udaykumar, Xu, Ye, and Mavrikakis, Manos. 2010. "Partial and complete reduction of O2 by hydrogen on transition metal surfaces". United States. https://doi.org/10.1016/j.susc.2010.05.026.
@article{osti_985769,
title = {Partial and complete reduction of O2 by hydrogen on transition metal surfaces},
author = {Ford, Denise and Nilekar, Anand Udaykumar and Xu, Ye and Mavrikakis, Manos},
abstractNote = {The metal-catalyzed reduction of di-oxygen (O{sub 2}) by hydrogen is at the heart of direct synthesis of hydrogen peroxide (HOOH) and power generation by proton exchange membrane fuel cells. Despite its apparent simplicity, how the reaction proceeds on different metals is not yet well understood. We present a systematic study of O{sub 2} reduction on the (111) facets of eight transition metals (Rh, Ir, Ni, Pd, Pt, Cu, Ag, and Au) based on periodic density functional theory (DFT-GGA) calculations. Analysis of ten surface elementary reaction steps suggests three selectivity regimes as a function of the binding energy of atomic oxygen (BEO), delineated by the opposite demands to catalyze O-O bond scission and O-H bond formation: The dissociative adsorption of O{sub 2} prevails on Ni, Rh, Ir, and Cu; the complete reduction to water via associative (peroxyl, peroxide, and aquoxyl) mechanisms prevails on Pd, Pt, and Ag; and HOOH formation prevails on Au. The reducing power of hydrogen is decreased electrochemically by increasing the electrode potential. This hinders the hydrogenation of oxygen species and shifts the optimal selectivity for water to less reactive metals. Our results point to the important role of the intrinsic reactivity of metals in the selectivity of O{sub 2} reduction, provide a unified basis for understanding the metal-catalyzed reduction of O{sub 2} to H{sub 2}O and HOOH, and offer useful insights for identifying new catalysts for desired oxygen reduction products.},
doi = {10.1016/j.susc.2010.05.026},
url = {https://www.osti.gov/biblio/985769}, journal = {Surface Science},
issn = {0039-6028},
number = 19-20,
volume = 604,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 2010},
month = {Fri Jan 01 00:00:00 EST 2010}
}