catalytic oxidation;
CO;
Pt(111);
Vienna ab initio simulation package (VASP);
D O I:
10.1016/S0039-6028(99)00061-8
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
The oxidation of CO on an oxygen precovered Pt(111) surface has been modelled via ab initio local-density calculations (including generalized gradient corrections) using the Vienna ab initio simulation package VASP. Reaction barriers and transition-states are determined using the nudged-elastic-band method. Based on the results from the calculations, a complete scenario of subsequent reactions is modelled: starting from a co-adsorption phase of molecular O-2 precursors and on-top adsorbed CO molecules at Theta(O2) = Theta(CO) = 1/4 half of the O-2 is desorbed (E-act = 0.75 eV). At this lower coverage, dissociation of O-2, and hence a bi-molecular reaction O-2 + CO-->CO2 + O, becomes possible (E-barr = 0.46 eV). Finally, the atomic oxygen at the surface may further react with CO to form CO2 (E-barr = 0.75 eV). (C) 1999 Elsevier Science B.V. All rights reserved.