(267g) A First-Principles Study of Support Effects On the Adsorption of CO On Pt/SrTiO3 (100)

The growth of oxide-supported metal thin films is crucial in numerous industrial applications such as catalysis and microelectronics. In this study, we used density functional theory (DFT) calculations to investigate CO adsorption on Pt metal films supported on SrTiO₃ (100). CO serves as a relatively simple probe to measure the support-induced changes to the metal electronic structure. CO adsorption on 1 ML of Pt on the SrO- and TiO₂-terminated SrTiO₃ (100) surface is ~40 % stronger than on bulk Pt (100). We examined coverage effects for CO on the 1ML Pt/ SrTiO₃ (100) surface, and find significant structural relaxation for adsorption sites on hollow and bridge sites as the coverage of CO is decreased from 0.25 to 0.125 ML. Bader analysis showed that the dominant charge transfer is between the 1 ML of Pt and CO adsorbate with the substrate showing little net charge transfer at SrO termination. Besides a strong charge transfer between 1 ML of Pt and CO, additional charge transfer from oxide substrate to 1 ML of Pt was found on the O-supported Pt atom. We also studied the CO adsorption on multiple monolayers of Pt. For both SrO- and TiO₂-termination, the adsorption energy of CO decreases rapidly with increasing thickness of the Pt film. By the third ML of Pt, the oxide-supported Pt films behave similarly to bulk Pt in terms of adsorption energy and site preference. Lastly, we will present ongoing work examining CO adsorption on Pt clusters with different sizes and shapes deposited on SrTiO₃ (100).