Adsorption of formate species on Cu(h,k,l) low index surfaces

We report a density functional theory study on the relative stability of formate species on Cu(h,k,l) low index surfaces using a range of exchange-correlation functionals. We find that these functionals predict similar geometries for the formate molecule adsorbed on the Cu surface. A comparison of the calculated vibrational transition energies of a perpendicular configuration of formate on Cu surface shows an excellent agreement with the experimental spectrum obtained from inelastic neutron spectroscopy. From the calculations on adsorption energy we find that formate is most stable on the Cu(110) surface as compared to Cu(111) and Cu(100) surfaces. Bader analysis shows that this feature could be related to the higher charge transfer from the Cu(110) surface and optimum charge density at the interfacial region due to bidirectional electron transfer between the formate and the Cu surface. Analysis of the partial density of states finds that in the -5.5 eV to -4.0 eV region, hybridization between O p and the non-axial Cu d(yz) and d(xz) orbitals takes place on the Cu(110) surface, which is energetically more favourable than on the other surfaces. (C) 2016 The Authors. Published by Elsevier B.V.