Chemisorption of isocyanate (NCO) on Pd(100) at different coverages

PATRICIA G. BELELLI; GRACIELA R. GARDA; MARÍA M. BRANDA; RICARDO M. FERULLO; NORBERTO J. CASTELLANI

Varna, Bulgaria

Conferencia; 12th International Conference on Theoretical Aspects on Catalysis; 2008

Universidad de Sofía

With the purpose of diminishing environmental pollution, the interest to improve the catalytic converter technology to control the automobile exhaust emissions is increasing. In reactions involving NOx reduction, the formation of NCO species was detected on Pt, Pd, Rh, Ir and Ru supported catalysts. The IR spectroscopy has determined that isocyanate forms on metal, linked by the N atom, and then spills over to the support where it stabilizes. On Pd(100), NCO was detected at 160 K by RAIR techniques remaining stable up to 300 K. On this surface, the frequency shifts for different monolayer coverages on Pd(100) surface were analyzed (Németh et al., J. Phys. Chem. C 111 (2007) 1424). In this work we have studied, using a periodic DFT method, the NCO adsorption on top, bridge and hollow sites on Pd(100) at different coverages (theta=0.11, 0.25, 0.5 and 1) by changing the unit cell sizes and the number of adsorbed NCO. The calculations have been performed using the VASP code.