Highly-Ordered PdIn Intermetallic Nanostructures Obtained from Heterobimetallic Acetate Complex: Formation and Catalytic Properties in Diphenylacetylene Hydrogenation.

Igor Mashkovsky,Galina Baeva,Ilya Yakushev,Michael Vargaftik,Alexander Stakheev,Alexander Rassolov,Pavel Markov,Galina Bragina

doi:10.3390/nano8100769

Abstract

Formation of PdIn intermetallic nanoparticles supported on α-Al2O3 was investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and hydrogen temperature-programmed desorption (H2-TPD) methods. The metals were loaded as heterobimetallic Pd(μ-O2CMe)4In(O2CMe) complex to ensure intimate contact between Pd and In. Reduction in H2 at 200 °C resulted in Pd-rich PdIn alloy as evidenced by XRD and the disappearance of Pd hydride. A minor amount of Pd1In1 intermetallic phase appeared after reduction at 200 °C and its formation was accomplished at 400 °C. Neither monometallic Pd or in nor other intermetallic structures were found after reduction at 400–600 °C. Catalytic performance of Pd1In1/α-Al2O3 was studied in the selective liquid-phase diphenylacetylene (DPA) hydrogenation. It was found that the reaction rate of undesired alkene hydrogenation is strongly reduced on Pd1In1 nanoparticles enabling effective kinetic control of the hydrogenation, and the catalyst demonstrated excellent selectivity to alkene.

Highlights

Nowadays, bimetallic metal-supported catalysts are widely used for a number of industrial and laboratory relevant reactions
Formation of PdIn intermetallic nanoparticles supported on α-Al2O3 was investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and hydrogen temperature-programmed desorption (H2-TPD) methods
Catalytic performance of Pd1In1/α-Al2O3 was studied in the selective liquid-phase diphenylacetylene (DPA) hydrogenation

Summary

Introduction

Bimetallic metal-supported catalysts are widely used for a number of industrial and laboratory relevant reactions. The specific combination of covalent and ionic interactions and the presence of conducting electrons results in peculiar combination and homogeneity of electronic and crystal structures, providing unique adsorption and catalytic properties of IMCs [1,2,9]. Another advantage of IMCs is its thermodynamic stability in comparison with traditional solid-solution alloys [2]. By selecting intermetallic compounds with suitable structures, the properties of active sites can be fitted to the reaction needs

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Conclusion