TY - JOUR
T1 - Geometric requirements for hydrocarbon catalytic sites on platinum surfaces
AU - Gao, Jie
AU - Zhao, Haibo
AU - Yang, Xiaofang
AU - Koel, Bruce E.
AU - Podkolzin, Simon G.
PY - 2014/4/1
Y1 - 2014/4/1
N2 - Vibrational spectroscopic measurements and density functional calculations were used to identify a preferential catalytic mechanism for the transformation of acetylene, HC-CH, to vinylidene, C-CH2, on surfaces of Pt-Sn ordered alloys. In this mechanism, two adjacent Pt atoms adsorb an acetylene molecule and a third neighboring Pt atom is required for stabilizing the reacting H atom during the transformation. Therefore, unlike a direct H shift along the C-C bond in organometallic compounds with a single transition-metal atom, this mechanism has a geometric site requirement of three adjacent Pt atoms in the form of a three-fold site. The same geometric site requirement is identified for preferential C-H bond cleavage of acetylene with the formation of adsorbed C-CH and H species. In the absence of three-fold Pt sites, the reaction mechanism changes, and reactions of H transfer and C-H bond cleavage are suppressed. A preferential catalytic mechanism has been identified for the transformation of acetylene to vinylidene on Pt-Sn surfaces. Unlike a direct H shift along the C-C bond in organometallic compounds, this mechanism requires three adjacent Pt atoms. The same requirement is identified for C-H bond cleavage. Without three-fold Pt sites, the reaction mechanism changes, and reactions of H transfer and C-H bond cleavage are suppressed.
AB - Vibrational spectroscopic measurements and density functional calculations were used to identify a preferential catalytic mechanism for the transformation of acetylene, HC-CH, to vinylidene, C-CH2, on surfaces of Pt-Sn ordered alloys. In this mechanism, two adjacent Pt atoms adsorb an acetylene molecule and a third neighboring Pt atom is required for stabilizing the reacting H atom during the transformation. Therefore, unlike a direct H shift along the C-C bond in organometallic compounds with a single transition-metal atom, this mechanism has a geometric site requirement of three adjacent Pt atoms in the form of a three-fold site. The same geometric site requirement is identified for preferential C-H bond cleavage of acetylene with the formation of adsorbed C-CH and H species. In the absence of three-fold Pt sites, the reaction mechanism changes, and reactions of H transfer and C-H bond cleavage are suppressed. A preferential catalytic mechanism has been identified for the transformation of acetylene to vinylidene on Pt-Sn surfaces. Unlike a direct H shift along the C-C bond in organometallic compounds, this mechanism requires three adjacent Pt atoms. The same requirement is identified for C-H bond cleavage. Without three-fold Pt sites, the reaction mechanism changes, and reactions of H transfer and C-H bond cleavage are suppressed.
KW - acetylene
KW - alloys
KW - heterogeneous catalysis
KW - platinum
KW - reaction mechanisms
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U2 - 10.1002/anie.201309043
DO - 10.1002/anie.201309043
M3 - Article
AN - SCOPUS:84897453927
SN - 1433-7851
VL - 53
SP - 3641
EP - 3644
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 14
ER -