Carbon-supported Ruthenium Nanoparticles Research Articles

Size and Structure Effects of Carbon-Supported Ruthenium Nanoparticles on Waste Polypropylene Hydrogenolysis Activity, Selectivity, and Product Microstructure

<b>Size and Structure Effects of Carbon-Supported Ruthenium Nanoparticles on Waste Polypropylene Hydrogenolysis Activity, Selectivity, and Product Microstructure</b>

Highly efficient and selective hydrogenation of quinolines at room temperature over Ru@NC-500 catalyst

Selective hydrogenation of quinolines into 1,2,3,4-tetrahydroquinolines under mild conditions holds tremendous promise for the green synthesis of a multitude of fine chemicals. Herein, we describe nitrogen-doped carbon supported ruthenium nanoparticles were robust for the mide and selective hydrogenation of quinolines to the corresponding 1,2,3,4-tetrahydroquinolines with both excellent activity and selectivity at 30∼50 °C and 10 bar H2.

Selective upgrading of biomass-derived benzylic ketones by (formic acid)–Pd/HPC–NH2 system with high efficiency under ambient conditions

Selective upgrading of biomass-derived benzylic ketones by (formic acid)–Pd/HPC–NH2 system with high efficiency under ambient conditions

Activated Carbon Supported Ruthenium Nanoparticles Catalyzed Synthesis of Imines from Aerobic Oxidation of Alcohols with Amines

Imines were synthesized from the cross-coupling of alcohols with amines catalyzed by activated carbon (AC) supported ruthenium nanoparticles under atmospheric molecular oxygen without aid of any additives. The readily prepared catalyst 5%Ru/AC showed good to excellent (yield > 90%) performances in the reaction of aromatic and heterocyclic alcohols with various amines, such as aromatic, aliphatic and heterocyclic amines. This protocol is simple, efficient, and environmentally friendly, and the catalyst can be easily recovered without major ruthenium loss. Imines were synthesized from the cross-coupling of alcohols with amines catalyzed by activated carbon (AC) supported ruthenium nanoparticles under atmospheric molecular oxygen without aid of any additives. This protocol is simple, efficient, and environment friendly, and the readily prepared catalyst 5%Ru/AC showed good to excellent performances in the reaction of aromatic and heterocyclic alcohols with various amines, such as aromatic, and aliphatic amines.

Sourcing hydrogen directly from wax

Chemistry Hydrogen is an appealing fuel because of the energy released in its reaction with oxygen and the nearly ideal safety profile of the sole product, water. The challenge lies in transporting and storing the hydrogen before its use. Gonzalez-Cortes et al. now show that simple paraffin wax can be an efficient source of hydrogen under the right circumstances. Specifically, they embedded carbon-supported ruthenium nanoparticles in the wax and then irradiated it with microwaves, thereby releasing up to half of the available gravimetric hydrogen content. The authors attribute the catalytic efficiency to a possible combination of local superheating and field-induced plasma formation. Sci. Rep. 10.1038/srep35315 (2016).

3D-interconnected hierarchical porous N-doped carbon supported ruthenium nanoparticles as an efficient catalyst for toluene and quinoline hydrogenation

NHPC can serve as an advanced catalyst support, which is attributed to its convenient mass transfer channel and nitrogen functionalization.

Direct Accessing the Nanostructure of Carbon Supported Ru−Se Based Catalysts by ASAXS

A structural model of selenium-modified ruthenium nanoparticles was derived from anomalous small-angle X-ray scattering (ASAXS) and small-angle neutron scattering (SANS) experiments and further approved and supported by TEM, XRD, and extended X-ray adsorption fine-structure (EXAFS) analysis. Carbon-supported ruthenium nanoparticles modified with selenium (RuSex/C) have been suggested as highly active and Pt-free cathode catalysts for the oxygen reduction reaction in PEM fuel cells. However, so far no definite conclusion regarding the nature of the catalytically active surface could be drawn. ASAXS and SANS experiments now revealed that the surface of Se modified Ru nanoparticles after reductive catalyst activation at elevated temperatures is not completely covered by Se. The Se rather forms patches on the Ru surface while the rest of the surface is covered by oxygen. It could be demonstrated that the different scattering contributions of the carbon black carrier and various metallic constituents of the supported nanoparticles can be well separated by means of ASAXS measurements. The structural model derived from the ASAXS energy dependencies could be confirmed by results of SANS measurements. Thus, the previously assumed core−shell model for the Se modified Ru particles was clearly disapproved.

Chemically modified cyclodextrins as supramolecular tools to generate carbon-supported ruthenium nanoparticles: An application towards gas phase hydrogenation

A series of carbon-supported ruthenium catalysts was synthesized from zerovalent ruthenium nanoparticles stabilized by randomly methylated cyclodextrins (α-, β- and γ-CD) followed by their adsorption onto the carbon support. The catalysts were characterized by N 2 physisorption and thermal analyses. The deposited ruthenium nanoparticles were characterized by transmission electron microscopy, which has highlighted predominantly spherical shapes with a mean diameter of 2.4 nm. Catalytic activity was investigated in the gas phase hydrogenation of o-, m- and p-xylene at 85 °C, both separately and in a two-component mixture ( o- and p-xylene). The catalyst prepared by a 1:3 concentration ratio of RuCl 3 to randomly methylated β-cyclodextrin exhibited the highest hydrogenation activity and stereoselectivity toward the formation of trans-dimethylcyclohexane. The β-cyclodextrin appeared as multifunctional molecular receptors enabling the stabilization and dispersion of the metallic nanoparticles onto the support and the promotion of the catalytic reaction through host–guest interactions.

Carbon-Supported Ruthenium Nanoparticles Stabilized by Methylated Cyclodextrins: A New Family of Heterogeneous Catalysts for the Gas-Phase Hydrogenation of Arenes

Carbon-Supported Ruthenium Nanoparticles Stabilized by Methylated Cyclodextrins: A New Family of Heterogeneous Catalysts for the Gas-Phase Hydrogenation of Arenes

Surface Modified Ruthenium Nanoparticles: Structural Investigation and Surface Analysis of a Novel Catalyst for Oxygen Reduction

Ruthenium catalysts modified by selenium are of interest as a methanol insensitive oxygen reduction catalyst in a polymer electrolyte membrane fuel cell for mobile application. To elucidate the structural and chemical features of unsupported and carbon supported ruthenium nanoparticles prepared by thermolysis of Ru3(CO)12 in an organic solvent with and without the presence of dissolved selenium, different bulk and surface sensitive methods such as transmission electron microscopy, X-ray diffractometry, thermogravimetry coupled with mass spectrometry, X-ray photoelectron spectroscopy, and extended X-ray absorption fine structure analysis were performed. It was found that the as-grown catalytic particles prepared without Se and handled under ambient conditions are distinguished by a ruthenium core of 4 nm size, the surface of which is covered by an amorphous ruthenium oxide/hydroxide and metal organic residues from the process of synthesis. In the presence of Se, Ru−Se and Se−O bondings have additionally been found at the surface. After heat treatment at 900 °C under vacuum, organic residues and ruthenium oxides could be removed. The particles have grown to a size of about 10 nm, the surfaces of which are covered by Ru−Se and Ru−SeO3 units. The as-grown and heat-treated catalysts were characterized electrochemically by cyclovoltammetry, rotating disk electrode with and without methanol in the electrolyte, and rotating ring disk electrode measurements to quantify H2O2 production. As expected from structural analysis, best results have been obtained with heat-treated, Se-modified ruthenium catalysts. It is proposed that in the heat-treated samples an interaction between Se2-, [Se2]2-, and SeO32- decorating the surface of the ruthenium particles is responsible for the improved oxygen reduction process.

Enhancement of oxygen electroreduction activity via surface modification of carbon supported ruthenium nanoparticles: A new class of electrocatalysts

Oxygen reduction catalysts have been prepared by modifying Ru/C catalysts (either commercial or self-made) using iron phenanthroline complexes adsorbed at the surface of the catalysts and heat treated at elevated temperatures. This new type of catalyst shows an oxygen reduction activity which is 3–5 times higher than the activity of an unmodified Ru/C catalyst. Furthermore, it is higher than that of catalysts based on Ru/C modified with Se, however, the activity of Pt/C is still not yet matched. Structural characterisation indicates that the catalysts consist of ruthenium nanoparticles. These nanoparticles most likely are covered by centres of type FeN x C y also found in carbon supported iron catalyst for oxygen reduction prepared by pyrolysis of iron, nitrogen and carbon via heat treatment steps.

Methanol electrooxidation on platinum spontaneously deposited on unsupported and carbon-supported ruthenium nanoparticles

Using an inverted spontaneous deposition method, unsupported Ru and carbon-supported 40% Ru nanoparticles were decorated with platinum after surface Ru oxides were reduced in the hydrogen atmosphere at 25 °C for 1 h. All samples that we produced in this way yielded high catalytic activity towards methanol oxidation at an electrode potential of interest to DMFC fuel cells. In the chronoamperometric experiment, the activity increased with the uptake of platinum to high Pt packing density values. The 40% C/Ru/Pt catalyst with an optimized packing density shows higher reactivity than that of an equivalent commercial, carbon-supported Pt/Ru catalyst. Reduction of Ru (and Ru/Pt) nanoparticles at higher than ambient temperature induced unacceptable level of sintering, and was avoided.

Electro-oxidation of methanol and ethanol using PtRu/C electrocatalysts prepared by spontaneous deposition of platinum on carbon-supported ruthenium nanoparticles

PtRu/C electrocatalysts were prepared by spontaneous deposition of Pt(II) and Pt(IV) ions on carbon-supported ruthenium nanoparticles, characterized by EDAX, TEM, cyclic voltammetry and tested for methanol and ethanol oxidation using the thin porous coating technique. The spontaneous deposition of Pt(II) ions was about two times more effective than Pt(IV) ions. The electrocatalysts were active for methanol and ethanol oxidation. For methanol oxidation good performance was obtained with high platinum coverage and for ethanol oxidation with low platinum coverage.