Theoretical study the influence of partial substitute noble metal Pd/Ag of PdAg-based catalyst by non-noble metal Ni/Cu for 1,3-Butadiene hydrogenation

Selective hydrogenation of 1,3-butadiene to form butene is an important tool for the removal of 1,3-butadiene which is a by-product of olefin production. AgPd bimetallic catalysts improved the butene selective, but its expensive cost is still an urgent problem. In this study, we introduced a third inexpensive metal Ni or Cu to replace part of the noble metal Pd or Ag in a common AgPd catalyst and studied the influence of the introduction on the hydrogenation reaction by DFT. Compared with the Ag3Pd and AgPd3 alloys, AgCuPd2 and Ag2NiPd hardly changed the adsorption energy of 1,3-butadiene and hydrogen but lowered the butene adsorption energy, which indicates that the addition of Cu or Ni metals can improve the butene selectivity. By calculating the reaction pathways, it was found that the energy barriers of 1,3-butadiene hydrogenation to butene on AgCuPd2 and Ag2NiPd was lower than that of Ag3Pd and AgPd3 alloys, while the energy barriers of butene further hydrogenation to butane was much larger than the desorption energy of butene. The partial replacement of Ag or Pd atom of AgPd alloys with Cu or Ni not only reduces the catalyst cost but also improves the conversion and selectivity of the hydrogenation reaction.