Ruthenium Trichloride Catalyst in Water: Ru Colloids versus Ru Dimer Characterization Investigations

Abstract

An easy-to-prepare ruthenium catalyst obtained from ruthenium(III) trichloride in water demonstrates efficient performances in the oxidation of several cycloalkanes with high selectivity toward the ketone. In this work, several physicochemical techniques were used to demonstrate the real nature of the ruthenium salt still unknown in water and to define the active species for this Csp 3 -H bond functionalization. From transmission electron microscopy analyses corroborated by SAXS analyses, spherical nanoobjects were observed with an average diameter of 1.75 nm, thus being in favor of the formation of reduced species. However, further investigations, based on X-ray scattering and absorption analyses, showed no evidence of the presence of a metallic Ru−Ru bond, proof of zerovalent nanoparticles, but the existence of Ru−O and Ru−Cl bonds, and thus the formation of a water-soluble complex. The EXAFS (extended X-ray absorption fine structure) spectra revealed the presence of an oxygen-bridged diruthenium complex [Ru(OH) x Cl 3−x ] 2 (μ-O) with a high oxidation state in agreement with catalytic results. This study constitutes a significant advance to determine the true nature of the RuCl 3 •3H 2 O salt in water and proves once again the invasive nature of the electron beam in microscopy experiments, routinely used in nanochemistry.

Chlorine-Modified Ru/TiO2 Catalyst for Selective Guaiacol Hydrodeoxygenation

“…As demonstrated in “Catalyst Characterization”, the characteristics of both Ru and TiO 2 are changed by the presence of Cl species. The initial precursor solution contains Ru n + , H 2 O, and Cl species, and the chemical state of Ru in solution is complicated . During thermal treatments in catalyst preparation, mainly the reduction process at 250 °C, the decomposition of NH 4 Cl occurs to produce gaseous HCl, which further interacts with Ru and Ti species.…”

“…The initial precursor solution contains Ru n+ , H 2 O, and Cl species, and the chemical state of Ru in solution is complicated. 71 During thermal treatments in catalyst preparation, mainly the reduction process at 250 °C, the decomposition of NH 4 Cl occurs to produce gaseous HCl, which further interacts with Ru and Ti species. One can infer that the presence of Cl alters the reduction behavior of Ru and the metal−support interaction, as evidenced by H 2 -TPR and XPS.…”

Development of a Sustainable Heterogeneous Catalyst Based on an Open-Cell Glass Foam Support: Application in Gas-Phase Ozone Decomposition

“…Zerovalent ruthenium nanoparticles (Ru(0)) were synthesized and characterized according to a methodology already published. , Briefly, ruthenium salt (RuCl 3 · 3H 2 O) was solubilized in water. A mixture of surfactant ( N , N -dimethyl- N -cetyl- N -(2-hydroxyethyl)­ammonium chloride salt, HEA16Cl, laboratory-made, 2 equiv) and reducing agent (NaBH 4 , Acros Organics, 2.5 equiv) was then added.…”

Rapid preparation of carbon‐supported ruthenium nanoparticles by magnetic induction heating for efficient hydrogen evolution reaction in both acidic and alkaline media

“…Consistent results were obtained from the Cl 2p spectra. From Figure 3B, one can clearly see that Ru‐200, Ru‐300, and Ru‐400 all possessed a doublet (green peaks) at 198.0/199.6 eV that can be assigned to Ru‐Cl x 24,28,29 . For Ru‐600, this doublet appears at a higher binding energy by (ca.…”

“…From Figure 3B, one can clearly see that Ru-200, Ru-300, and Ru-400 all possessed a doublet (green peaks) at 198.0/199.6 eV that can be assigned to Ru-Cl x . 24,28,29 For Ru-600, this doublet appears at a higher binding energy by (ca. 0.5 eV) suggesting weakened interaction between Cl and Ru, likely because of structural hinderance by a thin carbon shell, as observed in TEM measurements (Supporting information Figure S4C).…”