Synergetic effect of oxygen vacancy and Pd site on the interaction between Pd/Anatase TiO2(101) and formaldehyde: A density functional theory study

Abstract

Insights into the functions and the synergetic effects of oxygen vacancy and noble metal sites on the performance of the reducible oxide supported noble metal catalysts are very important in designing formaldehyde catalysts. Herein, the roles of oxygen vacancies and Pd sites, and their synergistic effect on the interaction between HCHO and Pd/Anatase TiO2(101) surface were systematically studied by a density functional theory (DFT) study. It is found that both the presence of oxygen vacancy and Pd site can promote the HCHO adsorption over TiO2(101) surface. The presence of Pd site is beneficial for the oxygen vacancy formation by reducing its formation energy. Furthermore, synergetic effect of oxygen vacancy and Pd site on the interaction between Pd/TiO2(101) and HCHO is demonstrated for the case with the co-presence of oxygen vacancy and Pd site. In this situation, the oxygen atom of HCHO molecular occupies the oxygen vacancy and the carbon atom of HCHO connects with the Pd site, and a larger adsorption energy is obtained in comparison with the cases with only oxygen vacancy or Pd site present. These results indicate that both oxygen vacancy manufacturing and Pd doping can strength the HCHO adsorption over TiO2(101) surface, and their synergistic effects further promote the interaction between HCHO and Pd/TiO2 catalyst, which is beneficial for the HCHO oxidation.