DFT study of CO adsorption on Pd-SnO2(110) surfaces

•We study CO adsorption on clean SnO2(110) and on Pd-SnO2 surfaces by DFT calculations.•CO adsorption is energetically more favourable in the presence of Pd.•The most stable adsorption sites are those with the C atom bonded to Pd.•A C-surface bond is formed producing a weakening of its first neighbours surface bonds.•CO molecule withdraws charge from the surface. We studied the effect of Pd on the adsorption of CO on the tin oxide surface SnO2(110) by Density Functional Theory calculations. Molecular CO adsorbs more strongly in the presence of Pd pre-deposited on the surface. The most stable adsorption sites are those bonded to the Pd atom near a Pd top position on a tilted configuration. In this case the CO distance increases, producing a weakening of the bond and the calculated stretching frequency decreases. Analysis of the atomic orbital interactions reveals that PdCO bonding involves C s - O p and p orbitals from CO, with Pd d orbitals. For CO sites bonded to Pd, CO bonds to the surface producing a weakening of the surface Pd-O bond. The electronic configuration analysis shows that in all cases the CO molecule withdraws charge from the surface.