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Ag/Au Mixed Sites Promote Oxidative Coupling of Methanol on the Alloy Surface
Author(s) -
Xu Bingjun,
Siler Cassandra G. F.,
Madix Robert J.,
Friend Cynthia M.
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201304837
Subject(s) - nanoporous , alloy , methyl formate , methanol , catalysis , formaldehyde , oxygen , materials science , oxidative coupling of methane , chemical engineering , inorganic chemistry , chemistry , nanotechnology , metallurgy , organic chemistry , engineering
Nanoporous gold, a dilute alloy of Ag in Au, activates molecular oxygen and promotes the oxygen‐assisted catalytic coupling of methanol. Because this trace amount of Ag inherent to nanoporous gold has been proposed as the source of oxygen activation, a thin film Ag/Au alloy surface was studied as a model system for probing the origin of this reactivity. Thin alloy layers of Ag x Au 1− x , with 0.15≤ x ≤0.40, were examined for dioxygen activation and methanol self‐coupling. These alloy surfaces recombine atomic oxygen at different temperatures depending on the alloy composition. Total conversion of methanol to selective oxidation products, that is, formaldehyde and methyl formate, was achieved at low initial oxygen coverage and at low temperature. Reaction channels for methyl formate formation occurred on both Au and Au/Ag mixed sites with a ratio, as was predicted from the local 2‐dimensional composition.