Tunable catalysis by reversible switching between Ru(III) single sites and Ru0 clusters in solid micelles
Résumé
Traditionally, catalytic active sites are robust; they do not change after a reaction. We show here that the Ru(III) active sites in a solid micellar Ru(III)@MCM catalyst can be controllably switched to Ru0 nanoclusters and vice versa by a mild treatment. The Ru(III) single-sites selectively catalyze the hydrogenation of functional groups such as carbonyl, and double and triple bonds in aromatic compounds via heterolytic H2 activation. The Ru0 nanoclusters in contrast are very active for hydrogenating aromatic rings. Ru0 nanoclusters are reversibly formed from the Ru(III) sites via hydrolysis and reduction as shown by XAS, HRTEM, CO adsorption, and DFT calculations.
The reported strategy offers reversible switching between oxidized and metallic states of Ru to perform different chemical transformations, achieving on-demand active sites.