Ruthenium Metal Research Articles

Near-threshold, steady state interaction of oxygen ions with transition metals: Sputtering and radiation enhanced diffusion

Transition metals used in semiconductor, photolithography and fusion applications interact with low energy oxygen ions. Understanding erosion, the nature of the formed oxide and depth of oxygen transport is necessary in mitigating unexpected performance of sensors, optics or plasma facing components. Oxide formation is governed by both the ion–target combination and the incident ion energy. We study the interaction of the transition metals molybdenum, ruthenium, palladium and tungsten, with oxygen ions in the energy region of 50–500 eV. Near-threshold sputtering of metals was experimentally measured and compared to predictions by the Monte Carlo code TRIDYN. Compositional changes and oxide thicknesses following sputtering were measured using Angle resolved X-ray photoelectron spectroscopy and subsequently compared to limiting oxide formed by atomic oxygen exposures. Sputter yields in some cases (ruthenium) were found to be sensitive to ion beam impurities such as ozone (<1% of background gas) leading to chemical sputtering. Ion induced oxide thicknesses (for molybdenum and tungsten) were found to be larger than those predicted by ballistic transport where sputtering is balanced by implantation. It is hypothesized that radiation enhanced diffusion of free oxygen leads to thicker oxide films at low ion energies.

Catalytic wet oxidation treatment of landfill leachate

The landfill leachate was treated by catalytic wet oxidation. The catalysts was prepared by impregnation method, and FSC was used as catalyst carrier. Fe and Co were used as catalyst active components and Ce was used as catalyst auxiliary, and noble metal ruthenium was added to prepare supported multi-component composite catalyst of Fe-Co-Ru-Ce/γ-Al2O3. The water sample pH, decolorization rate, COD removal rate and turbidity removal rate were used as evaluation indexes of catalyst activity. The catalysts were prepared under the conditions of calcination temperature of 450 °C and calcination time of 3 h. Under the same conditions, for the Landfill Leachate, the COD removal rate, decolorization rate, turbidity removal rate of the water samples reached 78.1%, 60.4% and 92.7%, respectively.

Microwave assisted synthesis of metallic Ru for the HOR and ORR

Metallic ruthenium electrocatalyst with activity for the hydrogen oxidation reaction and the oxygen reduction reaction has been synthesized by microwave irradiation at 180 °C in deionized water as reaction media. Characterization of the material by ATR-FTIR spectroscopy shows a complete decarbonylation of the precursor Ru3(CO)12 with formation of metallic Ru, which is confirmed by the corresponding x-ray diffraction analysis. Evaluation of the material’s electrocatalytic properties by the rotating disk electrode technique in 0.5 mol l−1 allows the study of hydrogen oxidation and oxygen reduction reaction using linear sweep voltammetry, exhibiting that the diffusional processes of H2 and O2 can be improved by modifying the electrocatalytic ink preparation.

Ruthenium derivatives attenuate LPS-induced inflammatory responses and liver injury via suppressing NF-κB signaling and free radical production.

Ruthenium metal complex has been shown to exert several chemical and biological activities. A series of three novel ruthenium derivatives (TQ 1, 2 and 4) were synthesized to evaluate the anti-inflammatory and hepatoprotective activities in lipopolysaccharide (LPS)-stimulated macrophages and mice liver injury. The hydroxyl radical (OH°) scavenging activity of these derivatives has also been evaluated. The results revealed that among the tested compounds, TQ-4 effectively attenuated LPS-induced abnormal alteration in liver histoarchistructure via reducing alanine transaminase (ALT) and aspartate transaminase (AST). This compound exhibited significant inhibition of inflammatory cytokines (TNF-α and IL-1β), inflammatory enzyme (iNOS), the component of NF-κB signaling pathway (p65) and JNK phosphorylation in LPS-induced mice liver tissues. In vitro results showed that TQ-4 had the best inhibition of NO production and iNOS expression in LPS-induced RAW 264.7 cells. Mechanistic approach indicated that TQ-4 inhibited the LPS-induced JNK phosphorylation, IκBα degradation, NF-κB p65 phosphorylation and its nuclear translocation, and hydroxyl radical (OH°) productions in RAW 264.7 cells. However, the compounds TQ-1 and 2 had no effects in this study. TQ-4 also inhibited LPS-induced OH° production. This study reveals the protective effect of TQ-4 against LPS-induced acute liver injury, inflammation, and oxidative reaction by destructing JNK/NF-κB signaling pathways. The result of this study may infer that TQ-4 might be a promising ruthenium metal derivative and/or therapeutic agent for treating liver injury.

Ruthenium Electrodeposition from Water-in-Salt Electrolytes and the Influence of Tetrabutylammonium

The use of water-in-salt electrolytes is evaluated for the electrodeposition of metallic ruthenium. The mechanisms of proton reduction inhibition by concentrated LiCl and dilute tetrabutylammonium is evaluated. Concentrated LiCl is found to disrupt the hydrogen bonding network within the solution bulk, whereas TBA is found to adsorb onto the electrode surface, blocking proton access. Ruthenium exists as a different complexed species in water-in-salt electrolytes vs dilute aqueous electrolytes, leading to a −300 mV shift in the deposition onset potential. Greater current efficiencies of Ru deposition can be obtained when depositing at proton overpotentials by the use of water-in-salt electrolytes, and TBA can offer further improvements. The grain structure and resistivities of Ru thin films are studied.

Catalysis with Colloidal Ruthenium Nanoparticles.

This review provides a synthetic overview of the recent research advancements addressing the topic of catalysis with colloidal ruthenium metal nanoparticles through the last five years. The aim is to enlighten the interest of ruthenium metal at the nanoscale for a selection of catalytic reactions performed in solution condition. The recent progress in nanochemistry allowed providing well-controlled ruthenium nanoparticles which served as models and allowed study of how their characteristics influence their catalytic properties. Although this parameter is not enough often taken into consideration the surface chemistry of ruthenium nanoparticles starts to be better understood. This offers thus a strong basis to better apprehend catalytic processes on the metal surface and also explore how these can be affected by the stabilizing molecules as well as the ruthenium crystallographic structure. Ruthenium nanoparticles have been reported for their application as catalysts in solution for diverse reactions. The main ones are reduction, oxidation, Fischer-Tropsch, C-H activation, CO2 transformation, and hydrogen production through amine borane dehydrogenation or water-splitting reactions, which will be reviewed here. Results obtained showed that ruthenium nanoparticles can be highly performant in these reactions, but efforts are still required in order to be able to rationalize the results. Beside their catalytic performance, ruthenium nanocatalysts are very good models in order to investigate key parameters for a better controlled nanocatalysis. This is a challenging but fundamental task in order to develop more efficient catalytic systems, namely more active and more selective catalysts able to work in mild conditions.

Variable structural bonding modes and antibacterial studies of thiosemicarbazone ligands of ruthenium, rhodium, and iridium metal complexes

Arene metal precursors on treatment with thiosemicarbazone ligands (L1, L2, and L3) yielded a series of cationic mono- and binuclear complexes (1–9) with N∩S bonding mode. In general, the complexes have been formulated as [(p-cymene)Ru(L)Cl]+ and [Cp*2M2(L)2]4+ where L = L1, L2, L3, M = Rh/Ir. Contrary to previous results [1], ruthenium complexes portrayed mononuclear bidentate chelation while rhodium and iridium complexes revealed dinuclear bridging coordination through sulfur and imine nitrogen atoms. All these complexes have been characterized by various spectroscopic techniques and antibacterial studies have been carried out for the complexes as well as the ligands, where 5 and 8 showed good inhibitory antibacterial activity.

Light-induced disruption of an acyl hydrazone link as a novel strategy for drug release and activation: isoniazid as a proof-of-concept case

Photocleavage of an acyl hydrazone bridge was achieved by conjugating isoniazid to a ruthenium(ii) metal complex through the generation of singlet oxygen, which released and activated the anti-tuberculosis pro-drug isoniazid.

A Laboratory-Based Case Study to Remove MTBE from Contaminated Water with Pure-WO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; and Nano-WO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; Catalysts Loaded with Ru and Pt

This article describes a laboratory-based case study to remove methyl tertiary butyl ether (MTBE) from contaminated water with tungsten oxide (WO3) catalysts loaded with ruthenium (Ru) and platinum (Pt) metals. Characterization of the synthesized catalysts were conducted by using the: (i) X-ray powder diffraction (XRD) data for the purity, (ii) visible light reaction condition for MTBE, (iii) solid-phase micro-extraction (SPME) technique incorporated with gas chromatography mass spectrometry (GC-MS) to assist the MTBE photo-oxidation process, (iv) catalyst syntheses from different concentrations of Ru in WO3, nano-WO3, Pt in nano-WO3, and (v) formation of byproducts during photocatalytic degradation of MTBE by using the GC-MS. The results revealed that the catalysts mainly consists of WO3 phase and there is no additional peaks from the metals, indicating that the Ru and Pt metals are well dispersed on WO3. Approximately 96% to 99% of the MTBE removal can quickly and accurately be achieved with a nanostructured WO3 catalyst loaded with Pt under visible light radiation between 2.5h and 3h. Moreover, with a nanocomposite WO3 catalyst loaded with Pt, photocatalytic MTBE removal is higher than with the pure WO3 catalyst loaded with Ru, and the pure nanostructured and micron-sized WO3. Finally, the formation of byproducts during the MTBE photocatalytic degradation revealed that the MTBE degradation essentially proceeds via formation of formic acid and 1,1-dimethylethyl ester before its complete degradation.

Iron- and cobalt-catalyzed C(sp3)-H bond functionalization reactions and their application in organic synthesis.

Direct C-H bond functionalization catalyzed by non-precious transition metals is an attractive strategy in synthetic chemistry. Compared with the precious metals rhodium, palladium, ruthenium, and iridium commonly used in this field, catalysis based on non-precious metals, especially the earth-abundant ones, is appealing due to the increasing demand for environmentally benign and sustainable chemical processes. Herein, developments in iron- and cobalt-catalyzed C(sp3)-H bond functionalization reactions are described, with an emphasis on their applications in organic synthesis, i.e., the synthesis of natural products and pharmaceuticals and/or their modification.

Visible light-assisted reduction of CO2 into formaldehyde by heteroleptic ruthenium metal complex–TiO2 hybrids in an aqueous medium

Reduction of CO2 was achieved by Ru(ii) complex-TiO2 hybrid under visible light in an aqueous neutral medium. The major product formaldehyde was obtained with trace of CO and CH4. Further, in situ formed CH2O was reacted with an amine to arrive useful products.

Hydrogenation of methanol to olefins over highly stable ruthenium oxide protonated fibrous ZSM5 catalyst

Olefins are known as a very decisive starting material for the production of particular polymer products. High demand of olefins as well as increasing of crude oil price make the production of olefins product became crucial issue. Catalytic methanol to olefins offered an alternative route in order to obtain olefins products. The protonated fibrous silica ZSM5 (HFZSM5) was synthesized by microwave assisted hydrothermal method and followed by impregnation of 0.5% ruthenium oxide (RuO2) metal onto the HFZSM5 catalyst (RuO2/HFZSM5). The catalysts were characterized using FESEM, TEM, nitrogen physisorption and pyridine adsorbed FTIR. FESEM and TEM results revealed the spherical morphology with dendrimeric silica fibers of HFZSM5 catalyst. Based on nitrogen physisorption result, slightly increase in surface area was observed after the addition of RuO2 onto the HFZSM5 catalyst surface. Obviously, the introduction of ruthenium metal has increased both Lewis and Brønsted acidity significantly, as observed by pyridine FTIR results. The catalytic methanol to olefin reaction was conducted within 473-673K at atmospheric pressure using continuous fixed bed reactor. The RuO2/HFZSM5 resulted in higher catalytic activity and performance which produced 93.92% olefin yields compared to HFZSM5 catalyst which obtained 88.60% olefin product.

Structure and magnetic properties of a novel heteroheptanuclear metal string complex [Ni3Ru2Ni2(μ7-teptra)4(NCS)2](PF6).

We report the synthesis of a novel heteroheptanuclear metal string complex (HMSC) [Ni3Ru2Ni2(μ7-teptra)4(NCS)2](PF6) 1 supported by tetra-pyridyl-tri-amine (H3teptra) ligands. We employed X-ray diffraction and other spectroscopic techniques to characterize the complex. The observed remarkably short Ru-Ru distance of 2.2499(3) Å for 1 is indicative of a unique metal-metal interaction in the mixed-valence [Ru2]5+ (S = 3/2) unit. The complex exhibits a relatively high magnetic moment value of 4.55 B.M. at 4 K, which increases rapidly to 6.00 B.M. at 30 K and remains at 6.11 B.M. from 50 to 300 K as shown by SQUID measurements, indicating a high spin (S≥ 3/2) system which is further supported by the analyses of EPR spectra at low temperatures. These magnetic behaviors can be ascribed to the result of spin-exchange interactions among multi-spin centers.

The one-step transformation of fructose to 2,5-diformylfuran over Ru metal supported on montmorillonite

Ruthenium metal supported on a montmorillonite (2 wt% Ru-MMT) catalyst have been synthesized and characterized. Catalyst found to be effective for the one-pot transformation of fructose to DFF showing an excellent yield with good recyclability.

Interphase-oxidized ruthenium metal with half-filled d-orbitals for hydrogen oxidation in an alkaline solution

The interphase-oxidized Ru clusters with half-filled 4d-orbitals can maintain a metallic surface for binding hydrogen at high anodic potential, leading to a high reactivity for hydrogen oxidation reaction in alkaline.

Comparison of Casimir forces and electrostatics from conductive SiC-Si/C and Ru surfaces

Comprehensive knowledge of Casimir forces and associated electrostatics from conductive SiC and Ru surfaces can be essential in diverse areas ranging from micro/nanodevice operation in harsh environments to multilayer coatings in advanced lithography technologies. Hence, the Casimir force was measured between an Au-coated microsphere and N-doped SiC samples with Si- and C-terminated faces, and the results were compared with the measurements using the same microsphere and a metallic Ruthenium surface. Electrostatic calibration showed that the Si- and C-faces behave differently with a nearly ~0.6-0.7 V difference in the contact potentials V0Si/C. We attribute this to a higher incorporation of N on the C-terminated face in the near surface region resulting in the formation of NOx and an increased work function compared to the Si-terminated surface which is in agreement with x-ray photoelectron spectroscopy data. Notably, the contact potential of the SiC-C face was closer to the metallic Ru-Au system. However, the measured optical properties of the SiC-Si/C terminated surfaces with ellipsometry did not show any substantial differences indicating that the effective depth of the Si/C terminating surface layers are significantly smaller than the photon penetration depth not leading to any differences in the calculated forces via Lifshitz theory. Nonetheless, the measured Casimir forces, after compensation of the electrostatics contributions, showed differences between the Si/C faces, whereas the comparison with the Lifshitz theory prediction shows better agreement for the SiC-Si face. Finally, comparison of the Casimir forces below 40 nm separations between the SiC-Si/C and Ru surfaces indicated that the short-range roughness effects on the Casimir force increase in magnitude with increasing metallic behavior of the plate surface.

Thermal atomic layer deposition of ruthenium metal thin films using nonoxidative coreactants

Atomic layer deposition (ALD) of ruthenium metal films is presented using (η4-2,3-dimethylbutadiene)(tricarbonyl)ruthenium [Ru(DMBD)(CO)3] with the coreactants 1,1-dimethylhydrazine, hydrazine, or tert-butylamine. The dependence of growth rate on precursor pulse lengths at 200 °C showed a saturative, self-limited behavior at ≥3.0 s for Ru(DMBD)(CO)3 and ≥0.1 s for 1,1-dimethylhydrazine. An ALD window was observed from 200 to 210 °C, with a growth rate of 0.42 Å/cycle. Films grown at 200 °C showed rms surface roughnesses of &amp;lt;1 nm. X-ray photoelectron spectroscopy of a 42 nm thick film grown at 200 °C revealed 90.6% ruthenium, 7.0% nitrogen, and 2.0% oxygen. Ruthenium films were deposited on patterned substrates with TiN surfaces using various treatments at 200 °C with 250 cycles. 42 nm thick ruthenium films grown at 200 °C were subjected to annealing studies under hydrogen and ammonia atmospheres at 400 °C, followed by rapid thermal annealing at 600 °C. These annealing procedures led to higher purity, more crystalline, and lower resistivity ruthenium films. The coreactants hydrazine and tert-butylamine were evaluated in ruthenium ALD trials using Ru(DMBD)(CO)3. Hydrazine gave a growth rate of 0.42 Å/cycle within a 200–205 °C ALD window, whereas tert-butylamine gave a growth rate of 0.25 Å/cycle at 200 °C.

Additional Lithium Storage on Dynamic Electrode Surface by Charge Redistribution in Inactive Ru Metal.

Beyond a traditional view that metal nanoparticles formed upon electrochemical reaction are inactive against lithium, recently their electrochemical participations are manifested and elucidated as catalytic and interfacial effects. Here, ruthenium metal composed of ≈5 nm nanoparticles is prepared and the pure ruthenium as a lithium-ion battery anode for complete understanding on anomalous lithium storage reaction mechanism is designed. In particular, the pure metal electrode is intended for eliminating the electrochemical reaction-derived Li2 O phase accompanied by catalytic Li2 O decomposition and the interfacial lithium storage at Ru/Li2 O phase boundary, and thereby focusing on the ruthenium itself in exploring its electrochemical reactivity. Intriguingly, unusual lithium storage not involving redox reactions with electron transfer but leading to lattice expansion is identified in the ruthenium electrode. Size-dependent charge redistribution at surface enables additional lithium adsorption to occur on the inactive but more environmentally sensitive nanoparticles, providing innovative insight into dynamic electrode environments in rechargeable lithium chemistry.

Modern Approaches in the Synthesis of Noble Metal Porphyrins for Their Practical Application (Review)

Being inert in the elemental state and as compounds, noble metals—ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, and gold—and rhenium, whose compounds have similar properties, form macrocyclic complexes with specific reactivity. This review highlights the achievements of the last two decades in the chemistry of complexes of these metals with porphyrins and some of their modified analogues. Emphasis is placed on the results of studies of approaches to synthesis and chemical, physical, electrochemical, electron-optical, magnetic, and catalytic properties of complexes as a theoretical basis for the practical application of compounds of this class in catalysis, photovoltaics, and medicine.

Hydrothermal Synthesis of Ruthenium Nanoparticles with a Metallic Core and a Ruthenium Carbide Shell for Low-Temperature Activation of CO2 to Methane.

Ruthenium nanoparticles with a core-shell structure formed by a core of metallic ruthenium and a shell of ruthenium carbide have been synthesized by a mild and easy hydrothermal treatment. The dual structure and composition of the nanoparticles have been determined by synchrotron X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS) analysis, and transmission electron microscopy (TEM) imaging. According to depth profile synchrotron XPS and X-ray diffraction (XRD) analysis, metallic ruthenium species predominate in the inner layers of the material, ruthenium carbide species being located on the upper surface layers. The ruthenium carbon catalysts presented herein are able to activate both CO2 and H2, exhibiting exceptional high activity for CO2 hydrogenation at low temperatures (160-200 °C) with 100% selectivity to methane, surpassing by far the most active Ru catalysts reported up to now. On the basis of catalytic studies and isotopic 13CO/12CO2/H2 experiments, the active sites responsible for this unprecedented activity can be associated with surface ruthenium carbide (RuC) species, which enable CO2 activation and transformation to methane via a direct CO2 hydrogenation mechanism. Both the high activity and the absence of CO in the gas effluent confer relevance to these catalysts for the Sabatier reaction, a chemical process with renewed interest for storing surplus renewable energy in the form of methane.