Influence of the exchange-correlation potential on the description of the molecular mechanism of oxygen dissociation by Au nanoparticles

The effect of the exchange-correlation functional on the molecular mechanism of dioxygen dissociation by Au nanoparticles is investigated using three Au nanoparticles of increasing size (Au-25, Au-38 and Au-79) and various exchange-correlation functionals (local density approach, PW91, PBE and RevPBE. The effect of the exchange-correlation functional on the calculated adsorption energies is quite large and systematic whereas the effect on the calculated energy barriers is much smaller. Implications for the molecular mechanism of O-2 dissociation, involving a competition between desorption and dissociation, are analyzed and discussed in detail.