Ruthenium and palladium bimetallic nanoparticles achieving functional parity with a rhodium cocatalyst for TiO-photocatalyzed ring hydrogenation of benzoic acid.

Our previous study showed that a rhodium (Rh) cocatalyst is indispensable for ring hydrogenation of benzoic acid over a titanium(IV) oxide (TiO) photocatalyst. In this study, we explored ring hydrogenation under an Rh-free condition by using two kinds of cocatalyst that were inactive for this reaction when used solely. Cyclohexanecarboxylic acid as the ring hydrogenation product was successfully obtained when ruthenium (Ru) and palladium (Pd) were simultaneously loaded on TiO, indicating that this bimetallic system can be used in place of an Rh cocatalyst in ring hydrogenation.