High-Density Formation of Metal/Oxide Interfacial Catalytic Active Sites through Hybrid Clustering.

We developed a method for preparing catalysts based on hybrid clusters that formed high-density metal/oxide interfacial active sites. A Ru-V hybrid cluster, [{Ru(cym)}4V6O19] (cym = p-cymene), was used as a precursor to prepare Ru-V catalysts. Transmission electron microscopy and X-ray absorption spectroscopy (XAS) analyses revealed that composite nanoparticles of Ru and V were formed through hybrid clustering, while conventional coimpregnation of Ru and V afforded separate nanoparticles. The activity of the Ru-V catalysts toward N-alkylation of amines with alcohols depended on the mixing method (hybrid clustering > coimpregnation > physical mixing ≈ pristine Ru). The formation mechanism of the composite nanoparticles from the hybrid cluster was revealed using in situ XAS analysis. Finally, we proposed a simple but efficient catalyst preparation method, based on in situ formation of hybrid cluster precursors combined with a conventional coimpregnation method.