DFT study of adsorption of hydrogen and carbon monoxide on PtxBi1-x/Pt(111) bimetallic overlayers: correlation to surface electronic properties

Analysis of the electronic properties of PtxBi1-x/Pt(111) bimetallic overlayers was performed by DFT calculation. The positions of the d-band centers and band widths were correlated using a triangular band model. In addition, the adsorption of hydrogen atoms as well as CO tolerance of selected PtxBi1-x/Pt(111) bimetallic overlayers were analysed. Excellent correlation was obtained of the adsorption energies of H and CO with d-band centers of platinum atoms on the studied surfaces. The red shift of Pt-H stretching vibration of adsorbed hydrogen, and decrease of work function upon adsorption of H were predicted. Analysis of hydrogen and CO chemisorption by means of the difference of the projected density of states was performed in order to identify d-states involved in bonding. The results obtained by calculations were compared with the experimental ones, where available.