Predicting CO adsorption on ZnO (10-10) and (11-20) surfaces using several van der Waals corrections to density functional theory

We study the adsorption of carbon monoxide (CO) onto the zinc oxide (ZnO) (10-10) and (11-20) surfaces. Our investigation utilizes Density Functional Theory (DFT) with the incorporation of van der Waals (vdW) interactions through a post DFT correction to the energy, and the addition of a nonlocal term to the correlation energy functional. We apply these methods to CO adsorption on locations around the pristine surfaces and defects such as a ZnO dimer defect and edge defects. Our results show that the inclusion of vdW interactions increases the calculated binding energy of CO to the ZnO surface, and that the vdW corrected binding energies exceed 1eV when the CO molecule settles within the ZnO dimer defect.