Effect of oxide supports on Pd-Ni bimetallic catalysts for 1,3-butadiene hydrogenation

Our previous work showed that the Pd-Ni bimetallic catalyst had better hydrogenation activity and 1-butene selectivity in the selective hydrogenation of 1,3-butadiene. In the present work, the effect of oxide supports on the hydrogenation of 1,3-butadiene was studied over Pd-Ni bimetallic catalysts supported on gamma-Al2O3, SiO2, CeO2, ZrO2 and TiO2. Transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) were used to characterize the particle size and the extent of Pd-Ni bimetallic bond formation, respectively. The support effect affected the bimetallic particle structure, but appeared to have no apparent influence in the hydrogenation activity. All the bimetallic catalysts showed similar to 100% selectivity to butenes; however, the supports affected the 1-butene selectivity. PdNi/gamma-Al2O3 showed the highest 1-butene selectivity of similar to 80% at 1,3-butadiene conversions lower than 50% but decreased rapidly at higher conversion. The different performance of the supports in 1-butene selectivity might be attributed to strong metal-support interaction (SMSI), the oxygen defects and the geometric/electronic effect on the catalysts. (C) 2014 Elsevier B.V. All rights reserved.