Effect of oxide support surface area on hydrogenation activity: Pt/Ni bimetallic catalysts supported on low and high surface area Al2O3 and ZrO2

Catalyst characterization and batch reactor studies have been performed to better understand the effects of oxide support and support surface area on low-temperature 1,3-butadiene hydrogenation over supported PtNi bimetallic catalysts. The supports studied in this work are: alpha-Al2O3 (10-16 m(2)/g), gamma-Al2O3 (80-120 m(2)/g), low surface area ZrO2 (20-30 m(2)/g), and high surface area ZrO2 (100-200 m(2)/g). Transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) were used to characterize the particle size and the extent of Pt-Ni bimetallic bond formation, respectively. The bimetallic catalysts supported on the two low surface area supports show larger metal nanoparticles; however, these catalysts also display greater extent of bimetallic bond formation, as characterized by the Pt L-III-edge EXAFS. After normalizing the hydrogenation rate constants for the two alumina-supported catalysts by the CO uptake values, the two rate constants appear very similar, suggesting that the bimetallic nanoparticles have similar structures on the alumina supports. In contrast, normalizing the hydrogenation rate constants for the two zirconia catalysts reveals that the catalyst supported on the high surface area zirconia is approximately twenty times less active, suggesting a strong metal-support interaction (SMSI) between the metal nanoparticles and the high surface area zirconia support. (C) 2011 Elsevier B.V. All rights reserved.