sophiecarenco

Catalysis by the colloidal suspension of nanoparticles has attracted considerable attention in recent years as it may combine interesting features: (i) the possibility of using inorganic catalysts, such as those of transition metal nanoparticles; (ii) the opportunity of adding well-designed ligands, as in homogeneous catalysis, to tune the activity and selectivity of a given reaction.

Here, we propose and illustrate the design of metal nanoparticles in colloidal suspension as Lewis acid partners of a “NanoFLP”. This concept was explored for the hydrogenation of alkynes such as phenylacetylene. However, to this date, no direct proof for the occurrence of an FLP has been provided on the examples that we developed. We discuss possible interpretations of the experimental data and ways of clarifying the mechanism involved.

S. Carenco, Comptes Rendus. Chim. 2024, 27, 395–403.

We present an experimental and theoretical study using model catalysts consisting of crystalline CoMnO_x nanoparticles and thin films, where Co and Mn are mixed at the sub-nm scale. Employing TEM and in-situ X-ray spectroscopies (XRD, APXPS, and XAS), we determine the catalyst’s atomic structure, chemical state, reactive species, and their evolution under FTS conditions. We show the concentration of CH_x, the key intermediates, increases rapidly on CoMnO_x, while no increase occurs without Mn. DFT simulations reveal that basic O sites in CoMnO_x bind hydrogen atoms resulting from H₂ dissociation on Co0 sites, making them less available to react with CH_x intermediates, thus hindering chain termination reactions, which promotes the formation of long-chain hydrocarbons.

H. Chen, Z. Lian, X. Zhao, J. Wan, P. F. Pieters, J. Oliver-Meseguer, J. Yang, E. Pach, S. Carenco, L. Treps, N. Liakakos, Y. Shan, V. Altoe, E. Wong, Z. Zhuo, F. Yang, J. Su, J. Guo, M. Blum, S. H. Lapidus, A. Hunt, I. Waluyo, H. Ogasawara, H. Zheng, P. Yang, A. T. Bell, N. López, M. Salmeron, Nat. Commun. 2024, 15, 10294

The adsorption properties of trimethylphosphine (PMe₃) on Ni nanoparticles (NPs) and extended surfaces were investigated via spin-polarized dispersion-corrected density functional theory calculations. The coverage effect of phosphine was explored by considering monoadsorption and monoshells on NPs and various adlayers from low coverage to saturation on surfaces. Icosahedral, ino-decahedral, cuboctahedral, truncated octahedral, and Marks-decahedral Ni nanoclusters at a size of 146–147 atoms were compared to the Ni(111), (100), and (110) surfaces.

S. Godoy-Gutierrez, A. Ropp, K. Azouzi, J. Pilmé, S. Carenco, D. Loffreda, J. Phys. Chem. C 2024, 128, 16501–16513.

We selected a commercial aminophosphine, HETAP, as the phosphorus precursor to develop a robust synthesis crystalline Co₂P and Ni₂P nanoparticles with high yields on a 9 mmol scale. Moreover, modification of the nanoparticles via the addition of a molecular Lewis base triggered catalytic activity of the colloidal suspension at low temperature for the hydrogenation of phenylacetylene. We delineated the most efficient phosphines in the case of a Ni₂P catalyst, using a stereoelectronic map of 13 phosphines.

A. Ropp , S. Carenco, Inorg. Chem. 2024, DOI 10.1021/acs.inorgchem.4c02743

Just published in the French journal "L'Actualité chimique": a feature article about our ERC Research program on NanoFLP, or "nanoparticles as partners in Frustrated Lewis Pairs".

It describes our recent works on this topic, with a focus on what where ou guidelines and purposes.

S. Carenco, L'Actualité Chimique 2024, 496, Juillet-Août

We designed a low-temperature synthetic route for CeO₂ nanorods. We employed near-ambient-pressure X-ray photoelectron spectroscopy to monitor the cerium surface oxidation state during the initial annealing of the nanopowder, followed by exposure to a moderate pressure of H₂. We demonstrate that H₂ homolytic splitting at cerium sites is the main activation process at 100 °C, leading to the oxidation of 30% of the surface cerium atoms, while the H₂ splitting at oxygen sites was absent.

R. F. André, J.-J. Gallet, F. Bournel, S. Carenco, ChemCatChem 2024, DOI 10.1002/cctc.202400163.

We show that phosphines with adequate steric hindrance (e.g., PnBu₃ and PiBu₃) lower the onset temperature for phenylacetylene hydrogenation by nickel NPs under 7 bar of H₂, by ca 10 to 20 °C depending on the NP diameter. This result is of conceptual value because the hydrogenation may have been driven by the frustrated Lewis pair (FLP) between the Lewis basic phosphine and the Lewis acid nickel surface, forming a so-called “NanoFLP”. Moreover, we demonstrated that less than 2 phosphines per Ni surface atom are enough for the effect to arise. We showed that other terminal alkynes, like 1-octyne, can be hydrogenated with this method.

K. Azouzi, A. Ropp, S. Carenco, ACS Catalysis 2024, DOI 10.1021/acscatal.4c00054.