Influence of carbon vacancies on the adsorption of Au on TiC(001): a first-principles study

In this work, it is found that the adsorption sites and geometries of Au clusters on TiC(001) surfaces containing carbon vacancies are significantly different from that without vacancies. In TiC(001) with carbon vacancies, the most preferential adsorption sites for Au are on top of vacancies sites, and then the sites neighboring the vacancies. The tendency for 3D Au clusters formation in TiC(001) with carbon vacancies is weaker and Au atoms are more likely to form rough 2D clusters. Furthermore, more charge is transferred from the substrate to Au and the polarization of electrons is stronger. In addition, the diffusion of Au on TiC(001) surface containing carbon vacancies is more difficult. The above affects can be helpful for improving the chemical activation of Au/TiC surfaces. Therefore, introducing carbon vacancies in the surfaces should be a very promising method to enhance the activation of Au/TiC systems.