Selective hydrogenation of 1,3-butadiene on Pd—Ni bimetallic catalyst: From model surfaces to supported catalysts

Display Omitted * PdNiPd(111) surface is more active for 1,3-butadiene hydrogenation than Pd(111). * EXAFS confirms the formation of bimetallic bonds in supported catalyst. * PdNi/[GREEK SMALL LETTER GAMMA]-Al2O3 has higher hydrogenation activity than its monometallic counterparts. * PdNi/[GREEK SMALL LETTER GAMMA]-Al2O3 gives ∼20% higher 1-butene selectivity than Pd/[GREEK SMALL LETTER GAMMA]-Al2O3. * PdNi/[GREEK SMALL LETTER GAMMA]-Al2O3 is a better catalyst for 1,3-butadiene removal. The selective hydrogenation of 1,3-butadiene serves as a means to purify the butene stream generated from cracking naphtha or gas oil. To identify selective hydrogenation catalysts, 1,3-butadiene was studied on single crystal Ni/Pd(111) bimetallic surfaces, utilizing density functional theory (DFT) calculations and temperature-programmed desorption (TPD). DFT calculations predicted that the Pd-terminated bimetallic surface should be more active and selective to produce 1-butene, which were verified experimentally using TPD. The promising results on model surfaces were extended to [GREEK SMALL LETTER GAMMA]-Al2O3-supported catalysts using both batch and flow reactors. Extended X-ray absorption fine structure (EXAFS) and transmission electron microscopy (TEM) confirmed the formation of bimetallic nanoparticles. The Pd[single bond]Ni bimetallic catalyst showed higher hydrogenation activity and 1-butene selectivity than the monometallic catalysts. The excellent correlation between model surfaces and supported catalysts demonstrates the feasibility of designing effective bimetallic catalysts for selective hydrogenation reactions.