Rh₂P Nanoparticles Stabilized by Carbon Patches for Hydroformylation of Olefins

Rh2P nanoparticles (NPs) have been identified as suitable mimics of [RhI(Ph3P)3]+, the benchmark of homogeneous catalysts in liquid-phase hydroformylation. For this reason, a fitted synthetic strategy is required to develop catalysts based exclusively on Rh2P NPs. To attain this, two synthetic pathways have been devised. In the first one, two separate sources of Rh and P were used. In the second one, the Wilkinson complex was employed as a unique source of Rh and P to probe the positive influence of the well-defined molecular organization on the preparation of dispersed and controlled Rh2P nanoparticles, stabilized by carbon patches formed during the pyrolysis treatment from PPh3. In addition, metallic Rh nanoparticles were also synthesized to be used as reference. All catalysts have been compared by means of: transmission electron microscopy, X-ray diffraction, and X-ray adsorption spectroscopy. The application of XAS to the study of Rh2P NPs is unusual and has been essential in the discussion of the results. Starting with a well-defined metal precursor leads to the exclusive formation of Rh2P NPs with excellent catalytic activity for the liquid-phase hydroformylation. The role of P is to modulate the particle size and the electronic configuration of Rh species, resulting in the improvement of the catalytic performance and the obtention of turnover frequencies of 5236 h–1 at 60 °C and 17,788 h–1 at 100 °C.