PdIn/Al2O3 Intermetallic Catalyst: Structure and Catalytic Characteristics in Selective Hydrogenation of Acetylene

Abstract

The structure and catalytic characteristics of a bimetallic catalyst containing Pd₁In₁ nanoparticles deposited on the surface of γ-Al₂O₃ were studied. The formation of intermetallic nanoparticles was determined by X-ray diffraction analysis and confirmed by X-ray photoelectron spectroscopy and IR spectroscopy of adsorbed CO. In the hydrogenation of acetylene in excess ethylene, PdIn/Al₂O₃ had significantly higher selectivity of ethylene formation (~86%) than monometallic Pd/Al₂O₃ (~35%). The high selectivity of PdIn/Al₂O₃ is explained by two factors: (1) the formation of monatomic Pd₁ sites isolated from one another by In atoms and (2) the change in the electronic state of Pd atoms in the intermetallic nanoparticles.