TiO₂(110)表面CO氧化的第一性原理研究：表面氧空位的作用

First principles study of CO oxidation on TiO2(110): the role of surface oxygen vacancies.

作者信息

Wu Xueyuan, Selloni Annabella, Nayak Saroj K

机构信息

Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.

出版信息

J Chem Phys. 2004 Mar 1;120(9):4512-6. doi: 10.1063/1.1636725.

DOI:10.1063/1.1636725

PMID:15268619

Abstract

The reactivities of the stoichiometric and partially reduced rutile TiO2(110) surfaces towards oxygen adsorption and carbon monoxide oxidation have been studied by means of periodic density functional theory calculations within the Car-Parrinello approach. O2 adsorption as well as CO oxidation are found to take place only in the presence of surface oxygen vacancies (partially reduced surface). The oxidation of CO by molecularly adsorbed O2 at the O-vacancy site is found to have an activation energy of about 0.4 eV. When the adsorbed O2 is dissociated, the resulting adatoms can oxidize incoming gas-phase CO molecules with no barrier. In all studied cases, once CO is oxidized to form CO2, the resulting surface is defect-free and no catalytic cycle can be established.

摘要

采用Car-Parrinello方法中的周期性密度泛函理论计算，研究了化学计量比和部分还原的金红石型TiO₂(110)表面对氧吸附和一氧化碳氧化的反应活性。发现O₂吸附以及CO氧化仅在存在表面氧空位（部分还原表面）的情况下发生。发现在氧空位处分子吸附的O₂对CO的氧化具有约0.4 eV的活化能。当吸附的O₂解离时，产生的吸附原子可以无障碍地氧化进入的气相CO分子。在所有研究的情况下，一旦CO被氧化形成CO₂，所得表面无缺陷，无法建立催化循环。