Evaluation Pd-Ni layered catalysts for selective hydrogenation of 1,3-butadiene: A theoretical perspective

GÓMEZ, GUILLERMINA; BELELLI PATRICIA GABRIELA; CABEZA, GABRIELA FERNANDA

Montevideo

Workshop; Workshop on Novel Methods for Electronic Structure Calculations; 2013

The partial hydrogenation of 1,3-butadiene as a model of fatty acid, to several C4H8 products, including 1-butene (1B), 2-butene (2B) and butan-1,3-diyl (B13R), on both Pd/Ni(111) and Pd3/Ni(111) bimetallic surfaces, was theoretically investigated using DFT methods. For that purpose, different intermediates, C4H7 and C4H8 radical species, were evaluated according to the Horiuti-Polanyi mechanism performed in two sequential steps. The whole process was found to be exothermic on Pd/Ni(111) and endothermic on Pd/Ni(111). Furthermore, the former surface, where the intermediate adsorptions are more favorable, exhibits lower activation barriers than Pd3/Ni(111). On both surfaces, the B13R formation is associated with high activation barriers through the pathways studied here; for this reason, it is extremely improbable to obtain B13R. Our calculations predict that, on the Pd/Ni(111) catalyst model, the products would be mainly the butene isomers, with a little more selectivity towards the 2B, at difference with respect to the pure Pd surface, and in agreement with experimental data.