Nickel-Doped Ceria Catalyst for Selective Acetylene Hydrogenation

Metallic nickel is known to be an active, but not a selective hydrogenation catalyst. On the other hand, oxidized nickel is not active for this reaction. Herein, we show that oxidized nickel doped into ceria provides an inexpensive catalyst for selective hydrogenation of acetylene in the presence of ethylene. Several synthesis techniques, including wet impregnation, melting, coprecipitation, and solution combustion were used to study how the method of nickel incorporation into the ceria crystal lattice affects catalytic behavior. Synthesis by coprecipitation and solution combustion favors nickel incorporation into the ceria lattice, while wet impregnation results in segregated nickel species on the ceria surface. Nickel ensembles on the ceria surface lead to over-hydrogenation of acetylene to ethane and poor ethylene selectivity. However, when nickel is incorporated into the ceria lattice, ethane formation is prevented even while achieving 100% conversion of acetylene. The higher catalytic activity and selectivity is supported by first principles calculations