First-Principles Study of CO Adsorption on Os Atom Doped Anatase TiO2 (101) Surface

In this paper, the first-principles is used to study the adsorption of CO on the surface of the anatase TiO2 (101) without and with an oxygen vacancy and noble metal (Os) dopant. The results show that TiO2 has well adsorption performance on CO, especially after adding defects, its adsorption performance is greatly improved. The adsorption energy of the pure system is -0.552 eV, the oxygen vacancy system is -1.591 eV, and the Os doping system is -3.971 eV. The analysis of the adsorption energy, bond length, charge distribution, the density of state and charge difference density shows that the adsorption mechanism and adsorption method of the three systems are different. The pure system is dominated by physical adsorption, and the carbon atom of CO has a strong interaction with Ti5C, but it fails to meet the conditions of forming a bond. The oxygen vacancy system is dominated by chemisorption, and the carbon atom of CO exerts a strong interaction with Ti2, resulting in a new bond C-Ti2. The Os doping system is dominated by chemisorption, and the carbon atom of CO exerts a strong interaction with the Os atom, which leads to the formation of C-Os bond.