Density Functional Theory based study of NO2 reduction by Cu, Ag and Au: nanoparticles versus extended surfaces

B. PASCUCCI; G.S. OTERO; P.G. BELELLI; F. ILLAS; M. M. BRANDA

Congreso; XXXIX Congreso Internacional de Químicos Teóricos de Expresión Latina (QUITEL); 2013

Combustion of fossil fuels containing even traces of elemental N causes important atmosphere damages due to NOx emission and is a main responsible of the acid rain. For this reason, catalytic NOx reduction has been extensively studied. Recently it has been found that Cu, Ag and Au nanoparticles are responsible for an enhanced catalytic performance towards this specific chemical reaction.1,2 In order to better understand this phenomenon, NO2 decomposition to NO + O catalyzed by cubo-octahedral nanoparticles of Cu, Ag and Au has been theoretically studied and the energy profile compared to the corresponding one for extended (111) surfaces. The study has been carried out at the density functional level using the PW91 form of the exchangecorrelationpotential using a plane wave basis set and with the projector augmented-wave (PAW) method to take into account the effect of core electrons in the valence electron density.3 A cutoff of 415 eV for the kinetic energy of the plane waves in the basis set allowed a convergence up to 10-4 eV in the total energy. The calculations were always performed at the spin-polarized level. The (111) surfaces were represented by slabs (2 x 2) of 5 layers and the cubo-octahedral nanoparticles were built by 19 atoms. All calculations were carried out using periodical DFT employing the Vienna Ab-initio Simulation Package (VASP).