氧空位作为金红石型TiO₂(110)表面上H₂S解离的活性位点：第一性原理研究

Oxygen vacancies as active sites for H2S dissociation on the rutile TiO2(110) surface: a first-principles study.

作者信息

Wang Fang, Wei Shiqian, Zhang Zhi, Patzke Great R, Zhou Ying

机构信息

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China.

The Center of New Energy Materials and Technology, School of Materials Science and Engineering, Southwest Petroleum University, Chengdu 610500, China.

出版信息

Phys Chem Chem Phys. 2016 Mar 7;18(9):6706-12. doi: 10.1039/c5cp06835e.

DOI:10.1039/c5cp06835e

PMID:26875868

Abstract

Spin-polarized DFT+U computations have been performed to investigate the role of oxygen vacancies in dissociating H2S on the rutile TiO2(110) surface. A bridged O2c atom is demonstrated to be the most energetically favorable oxygen vacancy site, which makes V(O2c) an electron donator center and induces an isolated defect level with narrowed band gaps. A H2S molecule is adsorbed dissociatively over V(O2c), but molecularly on the perfect surface. For H2S dissociation, the HS/H intermediate state reveals the best thermal stability on both defected and perfect surfaces. Moreover, potential energy surface analysis shows that V(O2c) reduces markedly the energy barriers for the paths along H2S dissociation. This indicates oxygen vacancies to be efficient trap centers for H2S dissociation, as evidenced by a significant interfacial charge transfer promoted by vacancies. This work could provide insights into the role of oxygen vacancies in facilitating the decomposition of H2S on rutile TiO2(110) surface.

摘要

已进行自旋极化密度泛函理论加U（Spin-polarized DFT+U）计算，以研究氧空位在金红石型TiO₂(110)表面解离H₂S过程中的作用。结果表明，桥连的O₂c原子是能量上最有利的氧空位位置，这使得V(O₂c)成为电子供体中心，并诱导出带隙变窄的孤立缺陷能级。H₂S分子在V(O₂c)上发生解离吸附，但在完美表面上以分子形式吸附。对于H₂S解离，HS/H中间态在缺陷表面和完美表面上均表现出最佳的热稳定性。此外，势能面分析表明，V(O₂c)显著降低了H₂S解离路径的能垒。这表明氧空位是H₂S解离的有效陷阱中心，空位促进的显著界面电荷转移证明了这一点。这项工作可为氧空位在促进金红石型TiO₂(110)表面H₂S分解中的作用提供见解。