Abstract

ANGELO, Antônio Carlos D.; SOUZA, Aguinaldo R. de; MORGON, Nelson H.  and  SAMBRANO, Júlio R.. Experimental (electrochemistry) and theoretical (ab initio and Density Functional Theory) studies of hydrogen and sulfide adsorption on palladium (100) surface. Quím. Nova [online]. 2001, vol.24, n.4, pp. 473-479. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422001000400008.

The adsorption of H and S^2- species on Pd (100) has been studied with ab initio, density-functional calculations and electrochemical methods. A cluster of five Pd atoms with a frozen geometry described the surface. The computational calculations were performed through the GAUSSIAN94 program, and the basis functions adapted to a pseudo-potential obtained by using the Generator Coordinate Method adapted to the this program. Using the cyclic voltammetry technique through a Model 283 Potentiostat/Galvanostat E.G.&G-PAR obtained the electrochemical results. The calculated chemisorption geometry has a Pd-H distance of 1.55Å, and the potential energy surface was calculated using the Becke3P86//(GCM/DFT/SBK) methodology. The adsorption of S^2- ions on Pd surface obtained both through comparison between the experimental and theoretical results, at MP2 level, suggest a S^2- absorption into the metallic cluster. The produced Pd-(S^2-) system was show to be very stable under the employed experimental conditions. The paper has shows the powerful aid of computational methods to interpret adsorption experimental data.

Keywords : ab initio; DFT; cyclic voltammetry; adsorption; hydrogen; sulfide.