Reactivity of transition metal atoms supported or not on TiO2(110) toward CO and H adsorption

Following our strategy to analyze the metal-support interaction, we present periodic DFT calculations for adsorption of metal atoms on a perfect rutile TiO2(110) surface (at low coverage, theta = 1/3) to investigate the interaction of an individual metal atom, M, with TiO2 and its consequence on the coadsorption of H and CO over M/TiO2. M under investigation varies in a systematic way from K to Zn. It is found that the presence of the support decreases or increases the strength of M-H or M-CO interaction according to the nature of M. The site of the adsorption for H and the formation of HCO/M also depend on M. From the left-to the right-hand side of the period, C and O both interact while O progressively detaches from M. On the contrary, for M = Fe-Cu, CO dissociation is more likely to happen. For CO and H coadsorption, two extreme cases emerge: For Ni, the hydrogen adsorbed should easily move on the support and CO dissociation is more likely. For Ti or Sc, H is easily coadsorbed with CO on the metal and CO hydrogenation could be the initial step.