Ni Promotion by Fe: What Benefits for Catalytic Hydrogenation?

Metallic nickel is known to efficiently catalyze hydrogenation reactions, but one of its major drawbacks lies in its lack of selectivity, linked to side-reactions of hydrogenolysis and over-hydrogenation. More selective hydrogenations can be obtained upon the introduction of a second metal in combination with Ni. Fe is an interesting choice, as it is a cheap and abundant metal. This review aims at discussing the advantages and constraints brought by the preparation procedures of bimetallic supported Ni-Fe nanoparticles, and at analyzing the benefits one can draw by substituting Ni-Fe supported catalysts for Ni monometallic systems for the catalytic hydrogenation of organic molecules. Specific formulations, such as Ni75Fe25, will be singled out for their high activity or selectivity, and the various hypotheses behind the roles played by Fe will be summarized.