Heterogeneous catalysts with rhodium supported on activated carbons. These are solid materials made of powdered activated carbons of different origin containing Rhodium particles finely dispersed on them.
Rhodium particles are anchored on the activated carbon surface by an SMSI (Strong Metal Support Interaction) bond, which is formed between the rhodium precursor coordination sphere and oxygenated functional groups on the carbon surface (SOGs).
Rhodium particles play a role in various reactions in which a heterogeneous Rh catalyst is involved, modifying the reaction’s kinetics by lowering the activation energy, but not the reaction’s thermodynamics (ΔG).
Among metals of the VIII B Group, rhodium is well-known for its strong tendency to form stable complexes, due to the availability of its “d” orbitals and to their tendency to complexation. Rhodium heterogeneous catalysts are used in some hydrogenation reactions, where selectivity is a sensitive parameter. For instance, when two or more functional groups are present in the reaction substrate, and all of them are prone to hydrogenation or hydrogenolysis, while only one group is required to be involved in the reaction.
