Rapid Synthesis of Rhodium–Palladium Alloy Nanocatalysts

The chemistry of metastable RhPd alloys is not well understood, and well‐characterized nanoparticle (NP) examples remain rare. Well‐defined and near‐monodisperse RhPd NPs were prepared in a simple one‐pot approach by using microwave‐assisted or conventional heating in reaction times as short as 30 s. The catalytic hydrogenation activity of supported RhPd NP catalysts revealed that short synthesis times resulted in the most‐active and most‐stable hydrogenation catalysts, whereas longer synthesis times promoted partial Rh‐Pd core–shell segregation. Relative to Rh NPs, RhPd NPs resisted deactivation over longer reaction times. Density functional theory (DFT) was employed to estimate the binding energies of H and alkenes on (1 1 1) Rh, Pd, and Rh 0.5 Pd 0.5 surfaces. The DFT results concurred with experiment and concluded that the alkene hydrogenation activity trend was of the order Pd<RhPd<Rh. Rh‐to‐Pd charge‐transfer in the RhPd alloys was found to play an important role in modulating the H binding energy.