Water-soluble single source precursors for homo- and hetero-metallic nanoparticle catalysts supported on nanocarbons

Abstract

Homo- and hetero-metallic catalysts were prepared in water from a single metal source and in a single step, and were tested in cinnamaldehyde selective hydrogenation. Two new water-soluble clusters, namely [Ru5C(CO)14(TPPTS)1] and [Ru5PtC(CO)15(TPPTS)1], were synthesized by the addition of phosphine TPPTS to starting homo- and hetero-metallic clusters soluble in organic solvents. They were then impregnated onto nanocarbons (CNF and CNT) in water at different pH values. Cluster deposition occurred via two adsorption modes and was the most successful when attractive electrostatic interactions took place. Thermal activation of these samples led to heterogeneous catalysts with a small mean particle size between 2 and 4nm. The home-made catalysts showed increased conversions and selectivities (up to 73%) towards the thermodynamically unfavored product cinnamyl alcohol compared to a commercial catalyst. The selectivity was in general higher with CNF support, with less oxygenated function and with bigger particles. The selectivity increased slightly with the addition of platinum to ruthenium but the activity was enhanced tremendously (up to 57% at t=30min).