Thermodynamic study of benzene and hydrogen coadsorption on Pd(111).

Periodic density functional theory (DFT) has been used to study the coadsorption of hydrogen and benzene on Pd(111). The most stable coverages are predicted by constructing the thermodynamic phase diagram as a function of gas-phase temperature and pressure. The common approximation that neglects vibrational contributions to the surface Gibbs free energy, using the PW91 functional, is compared to the one that includes vibrational contributions.