Synthesis of Supported Planar Iron Oxide Nanoparticles and Their Chemo- and Stereoselectivity for Hydrogenation of Alkynes

Nature uses enzymes to dissociate and transfer H-2 by combining Fe2+ and H+ acceptor/donor catalytic active sites. Following a biomimetic approach, it is reported here that very small planar Fe-2,Fe-3+ oxide nanoparticles (2.0 +/- 0.5 nm) supported on slightly acidic inorganic oxides (nanocrystalline TiO2, ZrO2, ZnO) act as bifunctional catalysts to dissociate and transfer H-2 to alkynes chemo- and stereoselectively. This catalyst is synthesized by oxidative dispersion of Fe-0 nanoparticles at the isoelectronic point of the support. The resulting Fe-2+,Fe-3+ solid catalyzes not only, in batch, the semihydrogenation of different alkynes with good yields but also the removal of acetylene from ethylene streams with >99.9% conversion and selectivity. These efficient and robust non-noble-metal catalysts, alternative to existing industrial technologies based on Pd, constitute a step forward toward the design of fully sustainable and nontoxic selective hydrogenation solid catalysts.