Ab initio atomistic thermodynamics study on the sulfur tolerance mechanism of the oxygen-enriched yttria-stabilized zirconia surface

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• 作者：Xingli Chu ; Yanxing Zhang ; Shasha Li ; Zongxian Yang
• 关键词：Oxygen-enriched YSZ ; Sulfur poisoning ; Phase diagram ; Atomistic thermodynamics method ; Surface regeneration
• 刊名：Surface Science
• 出版年：April, 2014
• 年：2014
• 卷：622
• 期：Complete
• 页码：16-23
• 全文大小：1478 K

文摘

The first-principles method based on density functional theory (DFT) is used to investigate the reaction mechanism for the adsorption of H₂S on the oxygen-enriched yttria-stabilized zirconia (YSZ + O) (111) surface. It is found that the H₂S dissociation processes have low energy barriers (< 0.5 eV) and high exothermicities (2.5 eV), and the dissociative S atoms may result in the poisoning of the YSZ + O surface by forming the SO and the hyposulfite (SO₂^{2 鈭?/sup>) species with very strong bonds to the surface. In addition, using the ab initio atomistic thermodynamics method, the surface regeneration or de-sulfurization process of a sulfur-poisoned (i.e. sulfur-covered) YSZ + O(111) surface is studied. According to the phase diagram, the adsorbed atomic sulfur can be oxidized to SO₂ and removed from the YSZ + O surface by introducing oxidizing reagents, e.g. O₂ and H₂O.}