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DFT Study of Synergistic Catalysis of the Water‐Gas‐Shift Reaction on Cu–Au Bimetallic Surfaces
Author(s) -
Saqlain Muhammad Adnan,
Hussain Akhtar,
Siddiq Dr Muhammad,
Leenaerts Ortwin,
Leitão Alexandre A.
Publication year - 2016
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201501312
Subject(s) - bimetallic strip , water gas shift reaction , catalysis , dissociation (chemistry) , chemistry , gibbs free energy , reaction rate constant , activation energy , density functional theory , water gas , inorganic chemistry , thermodynamics , kinetics , syngas , computational chemistry , organic chemistry , physics , quantum mechanics
The water‐gas‐shift reaction (WGSR) is an important industrial process that can be significantly enhanced at suitable catalyst surfaces. In this work, we investigate the catalytic behavior of metallic Cu(1 0 0) and bimetallic Cu–Au(1 0 0) surfaces. With density functional theory calculations, the variation in the Gibbs free energy (Δ G °), the activation barriers, and the rate constants for the WGSR are calculated. The variation in Δ G ° for water dissociation shows that the process is spontaneous up to 520 K on the bimetallic surface and up to 229 K on the Cu(1 0 0) surface. The calculated rate constants for the process also show that the bimetallic surface is much more reactive than the Cu(1 0 0) surface. The calculated pressure–temperature phase diagram for water dissociation shows that the partial pressure of H 2 O required for water dissociation on the bimetallic surface is substantially lower than that on the Cu(1 0 0) surface at all the studied temperatures. Additionally, the calculations demonstrate that the kinetics of the water‐gas‐shift reaction is dominated by redox processes on both the surfaces.