Cobalt nanoclusters coated with N-doped carbon for chemoselective nitroarene hydrogenation and tandem reactions in water

Abstract

The development of active and selective non-noble metal-based catalysts for the chemoselective reduction of nitrocompounds able to work in aquo media under mild conditions is an attractive research area. Herein,...

Rh2P Nanoparticles Stabilized by Carbon Patches for Hydroformylation of Olefins

“…In Figure , representative STEM images are shown for 1%Rh 2 P@C, 1%Rh-PPh 3 @C, and 1%Rh@C. Average particle sizes for these catalysts are very close: 2.1 nm for 1%Rh 2 P@C, 2.1 nm for 1%Rh-PPh 3 @C, and 2.2 nm for 1%Rh@C. It should be noted that, here, the pyrolysis temperature (800 °C) did not seem to foster the formation of bigger nanoparticles. This is consistent with our previous work, where materials were prepared at different temperatures of pyrolysis (400–800 °C), and there were no evidence of particle growth at the highest temperature . On the contrary, when the thermal treatment was performed in a stream of H 2 in Ar from 250 to 900 °C, Rh 2 P particles in the range of 2–5 nm were obtained at lower temperature, while at higher temperature, the average diameter increased up to 12 nm …”

“…This is consistent with our previous work, where materials were prepared at different temperatures of pyrolysis (400−800 °C), and there were no evidence of particle growth at the highest temperature. 23 On the contrary, when the thermal treatment was performed in a stream of H 2 in Ar from 250 to 900 °C, Rh 2 P particles in the range of 2−5 nm were obtained at lower temperature, while at higher temperature, the average diameter increased up to 12 nm. 21 In our case, HAADF-STEM results show that, for Rh 2 P@C at 5, 1, 0.5, and 0.3% Rh loadings, the particle mean sizes are 4.8, 2.1, 1.8, and 1.…”

“…This was also observed in a previous work of our group with nitrogenated ligands, which promoted the formation of smaller NPs than those without electron-donating ligands. 23 The catalyst preparation methods described here result in a better metal dispersion than reported before. 21,22 Energy-dispersive X-ray (EDX) and high-resolution transmission electron microscopy (HRTEM) revealed the presence of both phosphorus and rhodium in the same nanoparticles with 12.2% of phosphorus and 87.8% of rhodium for 1% Rh 2 P@C and 14.3% of P and 85.7% of Rh for 1%Rh-PPh 3 @C (Figure S19 and Table S1).…”

“…Based on that, herein, we report a straightforward, efficient, and robust synthesis of exclusive Rh 2 P nanoparticles promoted through a commercially available source of Rh and P, the Wilkinson complex. Rh 2 P nanoparticles were formed after incipient wetness impregnation on a carbon support followed by pyrolysis under a N 2 atmosphere, as we have achieved recently with a Co complex . In this work, the aim is to report a selective and alternative method for forming nanoparticles based on a single Rh 2 P phase from a well-defined single precursor and contribute to the reported strategies for their synthesis.…”

“…Rh 2 P nanoparticles were formed after incipient wetness impregnation on a carbon support followed by pyrolysis under a N 2 atmosphere, as we have achieved recently with a Co complex. 23 In this work, the aim is to report a selective and alternative method for forming nanoparticles based on a single Rh 2 P phase from a well-defined single precursor and contribute to the reported strategies for their synthesis. In fact, these Rh 2 P nanoparticles have shown a catalytic activity for hydroformylation comparable to the benchmark homogeneous catalyst with excellent stability of Rh 2 P nanoparticles based on deep post-catalysis studies.…”