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

Nature uses enzymes to dissociate and transfer H<sub>2</sub> by combining Fe<sup>2+</sup> and H<sup>+</sup> acceptor/donor catalytic active sites. Following a biomimetic approach, it is reported here that very small planar Fe<sup>2,3+</sup> oxide nanoparticles (2.0 ± 0.5 nm) supported on slightly acidic inorganic oxides (nanocrystalline TiO<sub>2</sub>, ZrO<sub>2</sub>, ZnO) act as bifunctional catalysts to dissociate and transfer H<sub>2</sub> to alkynes chemo- and stereoselectively. This catalyst is synthesized by oxidative dispersion of Fe<sup>0</sup> nanoparticles at the isoelectronic point of the support. The resulting Fe<sup>2+,3+</sup> 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.