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

GÓMEZ, GUILLERMINA; BELELLI, PATRICIA GABRIELA; CABEZA, GABRIELA FERNANDA; CASTELLANI, NORBERTO JORGE

JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 394 p. 151 - 161

1381-1169

The partial hydrogenation of 1,3-butadiene (13BD) 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 Pd3/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 transition state energies 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 toward 2B, in contrast to the pure Pd surface and in agreement with experimental data.