Hydrogenation of arenes, N-heteroaromatic compounds, and alkenes catalyzed by rhodium nanoparticles supported on magnesium oxide

A new catalyst composed of Rh nanoparticles supported on magnesium oxide was prepared by mild hydrogenation of a pre-adsorbed organometallic precursor, and characterized by TEM, XRD, XPS, and hydrogen chemisorption measurements. The catalyst contains 5 wt% Rh as ~50 nm metallic nanoparticles uniformly distributed on the surface of MgO, in turn made up of smaller (~2 nm) particles. This material is an efficient catalyst for the hydrogenation of arenes, N-heteroaromatic compounds, and alkenes under moderate reaction conditions. Analogous catalysts containing Rh nanoparticles on other rare earth oxide supports display similar catalytic properties and the hydrogenation activity correlates with the basicity of the support in the case of N-heterocycles, following the trend Rh/MgO < Rh/CaO < Rh/SrO.