The Surface Chemistry of Metal-Based Hydrogenation Catalysis

The promotion of hydrogenation reactions by transition-metal-based heterogeneous catalysts was established many decades ago but is still quite common in the chemical industry. Because of their importance, these processes have been studied in great detail from both fundamental and practical points of view, and much has been learned about them. However, some key questions remain unanswered, and solutions to specific industrial needs are still pending. In this Perspective, we discuss the state-of-the-art of our understanding of some of the fundamental issues associated with hydrogenation catalysis. From the mechanistic point of view, we use the example of olefin hydrogenation to assess the status of our knowledge on the adsorption of the organic reactants, the role that the strongly adsorbed carbonaceous deposits that form during reaction play in defining the catalytic kinetics, the mechanistic details of the hydrogen dissociative uptake and surface mobility during reaction, and the dynamic changes of the st...