Mechanistic investigations on the adsorption of thiophene over Zn₃NiO₄ bimetallic oxide cluster

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• 作者：Shengli Zhang ; Yonghong Zhang ; Shiping Huang ; Peng Wang ; Huiping Tian
• 关键词：Reactive adsorption ; Desulfurization mechanism ; Thiophene ; Zn3NiO4 cluster ; Density functional theory
• 刊名：Applied Surface Science
• 出版年：2012
• 出版时间：1 October, 2012
• 年：2012
• 卷：258
• 期：24
• 页码：10148-10153
• 全文大小：787 K

文摘

Desulfurization mechanism of thiophene was studied via reactive adsorption over a Zn₃NiO₄ cluster by density functional theory calculations. A gas-phase thiophene molecule is adsorbed on the Ni site instead of Zn site in the Zn₃NiO₄ adsorbent. When the first H₂ attacks C₄H₄S-adsorbent system, activation of the CS bonds occurs. When the second H₂ continues to attack the adsorption configuration, the CS bonds are cracked. In the process, H₂ plays an important role in the cleavage of the CS bonds of organic sulfur compound. The remaining S species on the Ni site of Zn₃NiO₄ adsorbent are dealt with two pathways. One is that nickel sulfide is reduced in the presence of H₂ to form H₂S with an energy barrier of 0.859 eV, and then the active nickel species is liberated from nickel sulfide in the S-adsorbent system. The other is that sulfur can be directly transferred from Ni site to Zn site in the adsorbent with a smaller energy barrier of 0.634 eV. Thus, in a reaction adsorption desulfurization, it favors the process that sulfur is directly transferred from Ni site to Zn site.