Interactions studies between NO and Ni/SiO2 catalyst by PM6 and DFT methods

CHAFICK BRENO RODRIGUES FLORES; ALEX GUTTERRES TARANTO; MOACYR COMAR JÚNIOR; NICOLÁS M. BERTERO

Ouro Preto - Minas Gerais

Simposio; XVI Simposio Brasilero de Química Teórica – SBQT 2011; 2011

SBQT

Investigation of the structural stability of compounds by both experimental and theoretical techniques is important for developing new compounds. In catalytic systems, theoretical approaches to simulate transition states, predict catalyst stability, or to aid in catalyst characterization has become possible through development of computational techniques. The objective of the present study is evaluating a theoretical model to study reaction mechanisms of heterogeneous catalysis. The structure of the catalyst Ni/SiO2 with adsorbed NO was generated and optimized with the GAUSSIAN 03W software using the semi-empirical PM6 and functional density theory (DFT). DFT calculations were performed using the functional hybrid B3LYP, with the appropriate LANL2DZ and 6-31G(d) base set for the nickel atom and non-metallic atoms, respectively. Geometric parameters obtained using PM6 were quite similar to those obtained using DFT. These results suggests that PM6 is able to simulate heterogeneous catalytic reactions as efficiently as the B3LYP/6-31G(d) method, but at a lower computational cost. In a further step, the semi-empirical method with transition metals will be applied to study the catalytic reduction of more complex and interesting substrates, such as acetophenone. Both the development of new active and selective catalysts and the investigation of kinetics of hydrogenation address for a better rationalizing in the production of valuable fine chemicals.