Crystal-Facet Effect of γ-Al₂O₃ on Supporting CrO_<i>x</i> for Catalytic Semihydrogenation of Acetylene

Abstract

With the successful preparation of γ-alumina with high-energy external surfaces such as {111} facets, the crystal-facet effect of γ-Al2O3 on surface-loaded CrOx has been explored for semihydrogenation of acetylene. Our results indeed demonstrate that the harmonious interaction of CrOx with traditional γ-Al2O3, the external surfaces of which are typically low-energy{110} facets, has caused a highly efficient performance for semihydrogenation of acetylene over CrOx/(110)γ-Al2O3 catalyst, whereas the activity of the CrOx/(111)γ-Al2O3 catalyst for acetylene hydrogenation is suppressed dramatically due to the limited formation of active Cr species, restrained by the high-energy {111} facets of γ-Al2O3. Furthermore, the use of inexpensive CrOx as the active component for semihydrogenation of acetylene is an economically friendly alternative relative to commercial precious Pd catalysts. This work sheds light on a strategy for exploiting the crystal-facet effect of the supports to purposefully tailor the catalytic properties.