The feed contains only C2-fractions and stoichiometrically added hydrogen. The low hydrogen concentration guarantees a high selectivity for conversion of acetylene to ethylene avoiding the overhydrogenation to ethane. However, it favors increased oligomer and green oil formation leading to shorter catalyst lifetimes in the acetylene hydrogenation. Due to the lower risk of reactor runaway, hydrogenation under tail-end conditions is most widely used in industry and well researched. The hydrogenation under front-end conditions takes place in front of the demethanizer and therefore, the feed contains high hydrogen concentration as well as carbon monoxide and methane. This carries the risk of overhydrogenation and hot spot formation. The key advantage of front-end conditions is the improved process integration combined with longer catalyst life cycles and has been studied intensively in the recent years. State of the art catalysts for both operation modes are palladium based catalyst systems. Owing to the low availability of palladium, its mining process consumes large amounts of fresh water and has a low atom economy, while producing high amounts of carbon dioxide due to high electricity consumption. It is therefore important to reduce or substitute the use of this critical raw material. In order to reduce the amount of palladium required and increase the selectivity of the acetylene hydrogenation reaction, palladium single-atom catalysts and palladium single sites incorporated into bimetallic systems have been the focus of recent research in this field. Some examples of bimetallic materials are PdAg , PdAu, PdIn, PdGa as well as PdCu and PdZn compounds and the incorporation of Pd into metal-organic frameworks (MOF). The substitution of palladium by more abundant metals as active species is even more favorable.