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Adsorption Mechanism of Acetylene Hydrogenation
Author(s) -
Xie Xuejia,
Song Xiuli,
Dong Wenyan,
Liang Zhenhai,
Fan Caimei,
Han Peide
Publication year - 2014
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201400182
Subject(s) - acetylene , chemistry , adsorption , mulliken population analysis , catalysis , molecule , carbon fibers , metal , chemical bond , triple bond , hydrogen bond , population , computational chemistry , density functional theory , organic chemistry , double bond , composite number , materials science , composite material , demography , sociology
First‐principles calculations are carried out to examine the adsorption of acetylene over the Pd (111) surface. A hydrogen adsorption system is initially investigated to confirm the reliability of the selected calculation method. Adsorption energies, Mulliken‐populations, overlap populations, charge density, and projected density of states (PDOS) are then calculated in the optimised acetylene adsorption system. Results show that C 2 H 2 molecule tends to adsorb through the threefold parallel‐bridge configuration that is computed to be the most stable. In this structure, the distance of the CH bond is calculated to be 1.09 Å, and the C‐C‐H bond angle is 128°. The distance of the CC bond in acetylene is 1.36 Å, increasing from 1.21 Å in the gas phase. Moreover, the CC bond overlap population decreases from 1.98 to 1.38, revealing that the carbon configuration in C 2 H 2 rehybridises from sp to sp 2 and beyond. The obtained results are compared with available experimental studies on acetylene hydrogenation on single‐metal surfaces. The PDOS study indicates that a carbonaceous layer may generate on the metal surface during acetylene adsorption. The carbonaceous layer can affect the adsorption and reaction of acetylene, thereby inactivating the metal surface. Our experiments also show that Pd exhibits high catalytic activity.