Adsorption Of Ru Research Articles

Adsorption and Surface Diffusion of Atomic Ru on TiN and SiO2: A First-Principles Study

Ruthenium (Ru) has been suggested as one of the promising materials for nanoscale interconnects to substitute copper (Cu) that is currently used in the semiconductor industry. Through density functional theory (DFT) calculations, we present the rationales for varying deposition behavior of Ru on different types of substrates. For the SiO2 and TiN substrates, with and without adsorbed hydrogen, our calculation results reveal the adsorption sites and their adsorption energy, the surface diffusion paths and their activation energy, and the surface diffusion coefficients. We confirm that the adsorption of Ru is more stable on TiN than on SiO2 substrates, and that the surface diffusion of Ru adatom is faster on TiN than on SiO2 surface.

Fe3O4@MnO2 inorganic magnetic sorbent: Preparation, characterization and application for Ru(III) ions sorption

ABSTRACT In this study, inorganic magnetic core-shell sorbent Fe3O4@MnO2 was prepared and used for the adsorption of Ru(III) ions from acidic aqueous solutions. The obtained magnetic sorbent was characterized by thermogravimetric analysis (TGA), differential scanning calorimetric (DSC) and X-ray diffraction (XRD). The sorption of Ru(III) from solutions of hydrochloric and nitric acids in concentration range from 0.01 mol L−1 to 0.5 mol L−1 on Fe3O4@MnO2 was examined. The selectivity of the Ru(III) sorption in the developed system was verified by the use of other ions like Co-60, Zn-65, Cs-137,Au-198, Pt-197, Cr-51, Sc-46, La-140 and described as a separation factor (α). The effects of contact time, dosage of magnetic sorbent and sorption capacity (Q) were checked too.

Structure and Stability of Small Metal Clusters on Stoichiometric and Defective 2D MoS2

Layered materials, such as MoS2, are of great interest to the research community due to their wide range of potential applications. They are of particular interest as supports for low dimensional metal catalysts, as well as for use in the electronics industry as ultra-thin diffusion barriers in semi-conductor device interconnects.Thus, understanding the interaction between a variety of metal structures and the MoS2 monolayer is of great importance. In previous studies the focus has been largely on the strength of the interaction between a single atom or a nanoparticle of a wide variety of metals, which creates a significant knowledge gap in thin film nucleation on 2D materials. To begin addressing this deficit, we present a density functional theory (DFT) study of the adsorption of small metal structures, with up to four atoms, on a monolayer of MoS2. The metals of interest are Cu, Co and Ru, chosen for their relevance in electronics applications. We show how the metal-substrate interaction changes depending on the particular metal, as well as the mode of adsorption and overall nanocluster structure. Further, we show the effect that the presence of a sulphur vacancy in the monolayer has on the metal-substrate interaction, as this is a commonly observed defect.The strength of interaction between the metals and MoS2 is in the order Co > Ru > Cu. The effect of adsorption on MoS2 is localised to the metal cluster, however depending on the particular structure, some distortions of the MoS2 lattice can be observed upon adsorption of Ru.

Cu(II) oxo/hydroxides stabilized by ZSM-5 zeolite as an efficient and robust catalyst for chemical and photochemical water oxidation with Ru(bpy)33+

Water oxidation is the bottleneck of the water splitting process. A novel highly efficient and stable for many cycles heterogeneous Cu-contained catalysts supported on MFI-type zeolite (1% Cu-ZSM-5) for water oxidation were prepared. Oxo/hydroxo complexes of copper (II) were stabilized in the zeolite channels via polycondensation. The analysis of the electron states of copper in the Cu-containing zeolite-based catalysts using EPR and UV–vis DR techniques revealed that the catalytic efficiency of Cu(II) state in zeolite grew up in the series: [Cu(NH3)4]2+ < isolated [Cu(H2O)6]2+ << Cu(OH)x-like and CuOx-like nanoclusters in mesopores << CuOx-like and Cu(OH)x-like complexes in channels < [Cu2(OH)2]2+ complexes in channels. The catalyst containing [Cu2(OH)2]2+ complexes in channels provided the yields of oxygen as high as 60 and 64 % of the stoichiometric quantity at pH 9.2–10.0 in the dark reaction with one-electron oxidant Ru(bpy)33+. Nevertheless, Cu(OH)x-like and [Cu2(OH)2]2+ complexes stabilized in the ZSM-5 channels decomposed easily under the conditions of the photocatalytic reaction. At the same time, the oxygen yield reached 92 % in photocatalytic system Ru(bpy)32+/S2O82− in the presence of 1%Cu-ZSM-5 containing CuOx-like complexes stabilized in the channels. The adsorption of Ru(bpy)32+ on the surface of 1%Cu-ZSM-5 containing CuOx-like complexes provided the increase of the reaction rate in 1.6 times and achieved the oxygen yield up to 98 % to stoichiometry. This indicated the strong effect of concurrent processes of Ru(bpy)32+ and Ru(bpy)33+ adsorption/desorption at the catalyst active site on the rate of oxygen evolution.

Adatom modified shape-controlled platinum nanoparticles towards ethanol oxidation

Different adatom modified shape-controlled Pt nanoparticles have been prepared and their electrocatalytic properties have been evaluated toward ethanol electrooxidation. Based on previous findings with Pt model surfaces, Sn, Rh, Ru and Pb adatoms have been selected as promising surface modifiers. The different adatoms have been gradually incorporated on the surface of the preferentially oriented (100) and (111) Pt nanoparticles under electrochemical conditions. The results obtained in 0.5M H2SO4 indicated that, among the selected adatoms, Sn-modified nanoparticles displayed not only a significant shift to negative values on the onset potential of the ethanol oxidation, but also an important decrease on the hysteresis between the positive and negative sweeps. Interestingly, in chronoamperometic measurements at 0.6V, the oxidation enhancement factors have been found to be dependent on the surface structure of the Pt nanoparticles. On the other hand, Ru and Pb-modified Pt nanoparticles only presented a rather small oxidation enhancement, whereas the activity of the Rh-modified Pt nanoparticles clearly diminished. In alkaline solutions, the oxidation mechanism changes, and the adsorption of Rh, Sn and Pb on the platinum surfaces just displays small catalytic effect at lower coverage for the potential onset in the voltammetric experiments. Ru adsorption does not present any positive effect over the reaction.

Adsorption of Ru, Ce and Eu radionuclides within naturally precipitated polycrystalline calcium carbonate under acidic environment

106Ru, 144Ce and 152+154Eu radiotracers sorption experiments (pH: 1–6) have been carried out with polycrystalline columnar/microcrystalline calcite and aragonite obtained from a stalagmite of Dharamjali cave, India. The different domains of the sample were powdered and thoroughly studied using electron microscopic and X-ray spectroscopic techniques. Both 106Ru and 144Ce exhibited higher sorption within calcite varieties compared to aragonite and increased with rising pH, while it showed reverse relation in case of 152+154Eu. Further, it is noted that aragonite offers the highest K d values for 152+154Eu, whereas 106Ru and 144Ce prefer calcite.

Antimicrobial ruthenium complex coating on the surface of titanium alloy. High efficiency anticorrosion protection of ruthenium complex

A ruthenium complex was prepared and structurally characterized using various techniques. Antibacterial and antifungal activities of ruthenium complex were evaluated. High significant antimicrobial activity against Escherichia coli, Staphylococcus aureus and Candida albicans was recorded. Minor cytotoxicity records were reported at the highest concentration level using MTT assay. The influence of Cu(II), Cr(III), Fe(III) and Ru(III) metal ions of salen Schiff base on the corrosion resistance of Ti-alloy in 0.5M HCl was studied. In vitro corrosion resistance was investigated using electrochemical impedance spectroscopy (EIS) measurements and confirmed by surface examination via scanning electron microscope (SEM) technique. Both impedance and phase angle maximum (θmax) values were at maximum in the case of the ruthenium complex with promising antibacterial and antifungal activities. The surface film created by the ruthenium complex was highly resistant against attack or deterioration by bacteria. The EIS study showed high impedance values for the ruthenium complex with increasing exposure time up to 8days. SEM images showed uniform distribution and adsorption of Ru(III) ions on Ti-alloy surface. The ruthenium complex, as a model of organic–inorganic hybrid complex, offered new prospects with desired properties in industrial and medical applications.

Removal of Ruthenium from Aqueous Solution by Clinoptilolite

AbstractRuthenium compounds are highly toxic and carcinogenic. In the present study, clinoptilolite was used in the removal of Ru species from aqueous solutions. Clinoptilolite is a good choice of sorbents because it is naturally abundant and therefore cheap. After the process where Ru was removed from the aqueous solution, the clinoptilolite was characterized by X-ray diffraction, X-ray fluorescence, thermogravimetric analysis, and Fourier-transform infrared spectroscopy techniques. The influence of pH, contact time, and temperature on the adsorption of Ru was investigated and the optimum conditions were found to be 2 h of contact time and pH = 2. Pseudo first-order, pseudo second-order, Elovich, and intra-particle diffusion models were used to analyze the adsorption-rate data. The pseudo second-order model was found to be the best kinetics model in terms of matching the experimental results obtained. Adsorption isotherms were constructed to assess the maximum adsorption capacity of clinoptilolite. The Langmuir model fitted the data reasonably well in terms of regression coefficients. Adsorption studies were also performed at different temperatures to calculate the thermodynamic parameters. The numerical value of ΔG0 decreased with increasing temperature, indicating that adsorption is favored at higher temperatures. The positive values of ΔH0 corresponded to the endothermic nature of the adsorption processes. The proposed method of removal is applicable at an industrial scale.

Hydrogen generation from sodium borohydride solution using a ruthenium supported on graphite catalyst

The catalyst with high activity and durability plays a crucial role in the hydrogen generation systems for the portable fuel cell generators. In the present study, a ruthenium supported on graphite catalyst (Ru/G) for hydrogen generation from sodium borohydride (NaBH 4) solution is prepared by a modified impregnation method. This is done by surface pretreatment with NH 2 functionalization via silanization, followed by adsorption of Ru (III) ion onto the surface, and then reduced by a reducing agent. The obtained catalyst is characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Very uniform Ru nanoparticles with sizes of about 10 nm are chemically bonded on the graphite surface. The hydrolysis kinetics measurements show that the concentrations of NaBH 4 and NaOH all exert considerable influence on the catalytic activity of Ru/G catalyst towards the hydrolysis reaction of NaBH 4. A hydrogen generation rate of 32.3 L min −1 g −1 (Ru) in a 10 wt.% NaBH 4 + 5 wt.% NaOH solution has been achieved, which is comparable to other noble catalysts that have been reported.

Development of an experimental protocol for uptake studies of metal compounds in adherent tumor cells

Cellular uptake is being widely investigated in the context of diverse biological activities of metal compounds on the cellular level. However, the applied techniques differ considerably, and a validated methodology is not at hand. Therefore, we have varied numerous aspects of sample preparation of the human colon carcinoma cell line SW480 exposed in vitro to the tumor-inhibiting metal complexes cisplatin and indazolium trans-[tetrachlorobis(1H-indazole)ruthenate(iii)] (KP1019) prior to analysis with ICP-MS, and the results were found to be tremendously influenced by adsorption to the culture dishes. Adsorption to culture plates increases linearly with the concentration of KP1019, depends on the protein content of the medium, the duration of contact to protein-containing medium prior to drug addition and the hydrophilicity/lipophilicity of the compound. For varying degrees of cell confluence, adsorption of Ru hardly differs from cell-free experiments. Desorption from the plates contributes to total Ru detected in dependence on the cell harvesting method. Desorption kinetics for lysis in HNO(3) and tetramethylammonium hydroxide (TMAH) are comparable, but TMAH is a more potent desorbant. Sample storage conditions prior to analysis influence significantly the recovery of analyte. Protocols using cell lysis in the culture plate without proper corrections run the risk of producing artefacts resulting from metal adsorption/desorption to an extent comparable with the actual cellular content. However, experimental protocols reported in the literature frequently do not contain information whether adsorption or blank correction were performed and should be regarded with caution, especially if lysis was performed directly in the culture dishes.

Polymer Films on Electrodes: Investigation of Ion Transport at Poly(3,4-ethylenedioxythiophene) Films by Scanning Electrochemical Microscopy

Electropolymerization, morphology characterization, and ion transport of poly(3,4-ethylenedioxythiophene) (PEDOT) films doped with different counterions (chloride, ferrocyanide (FCN), and poly(p-styrenesulfonate) (PSS-)) on a platinum electrode were investigated using scanning electrochemical microscopy (SECM) during both potential step (chronocoulometric) and cyclic voltammetric scans. An ultramicroelectrode (UME) tip was positioned close to the surface of a PEDOT-modified substrate electrode, and the responses of both electrodes to a substrate potential step or linear sweep were monitored simultaneously. Chloride or ferrocyanide (FCN) ejection during PEDOT reduction was shown to be a function of the reduction potential. The nature of the cation in the bulk solution was not found to be important in the kinetics of ion transport in PEDOT+/FCN- films. Direct evidence for the incorporation of cations of Ru(NH3)6(3+/2+) in a PEDOT film during its reduction was also obtained by SECM measurements. The adsorption of Ru(NH3)6(3+) in fully oxidized PEDOT+/PSS- films was observed and attributed to ion exchange between the Na+ co-ion of PSS- and Ru(NH3)6(3+) in the bulk solution.

Tris(2,2′-bipyridyl)ruthenium(II) electrogenerated chemiluminescence sensor based on carbon nantube dispersed in sol–gel-derived titania–Nafion composite films

A highly sensitive and stable tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy) 3 2+) electrogenerated chemiluminescence (ECL) sensor was developed based on carbon nanotube (CNT) dispersed in mesoporous composite films of sol–gel titania and perfluorosulfonated ionomer (Nafion). Single-wall (SWCNT) and multi-wall carbon nanotubes (MWCNT) can be easily dispersed in the titania–Nafion composite solution. The hydrophobic CNT in the titania–Nafion composite films coated on a glassy carbon electrode certainly increased the amount of Ru(bpy) 3 2+ immobilized in the ECL sensor by adsorption of Ru(bpy) 3 2+ onto CNT surface, the electrocatalytic activity towards the oxidation of hydrophobic analytes, and the electronic conductivity of the composite films. Therefore, the present ECL sensor based on the CNT–titania–Nafion showed improved ECL sensitivity for tripropylamine (TPA) compared to the ECL sensors based on both titania–Nafion composite films without CNT and pure Nafion films. The present Ru(bpy) 3 2+ ECL sensor based on the MWCNT–titania––Nafion composite gave a linear response ( R 2 = 0.999) for TPA concentration from 50 nM to 1.0 mM with a remarkable detection limit (S/N = 3) of 10 nM while the ECL sensors based on titania–Nafion composite without MWCNT, pure Nafion films, and MWCNT–Nafion composite gave a detection limit of 0.1 μM, 1 μM, and 50 nM, respectively. The present ECL sensor showed outstanding long-term stability (no signal loss for 4 months).

Assembly of thin mesoporous titania films and their effects on the voltammetry of weakly adsorbing redox systems

Titania (anatase) films composed of nanoparticulate building blocks are formed in a layer-by-layer deposition procedure followed by calcination. Field emission gun scanning electron microscopy (FEGSEM) and conducting probe atomic force microscopy (C-AFM) techniques are used to assess the topography and electrical conductivity of the resulting titania films in the dry state. Two types of molecular binder, cyclohexane hexacarboxylic acid and phytic acid, are employed in the deposition process. The surface charge of the resulting titania films is dramatically affected by the presence of phosphate (from phytic acid) after pyrolysis of the molecular binder. Voltammetric responses for the Ru ( NH 3 ) 6 3 + / 2 + redox system obtained at mesoporous titania coated electrodes immersed in aqueous KCl are strongly affected by the adsorption of Ru ( NH 3 ) 6 3 + in the presence of phosphate. In order to further investigate the effects of the mesoporous membrane on voltammetric features, an approximate adsorption and transport model supported by a simple numerical simulation (of explicit finite-difference type) with reversible adsorption/desorption equilibria is developed. Based on the comparison of experimental and numerical data, it is proposed that the electrical conductivity (electron diffusion) within the wet titania film in the potential range where the reduction of Ru ( NH 3 ) 6 3 + occurs is important in addition to ion transport.

Ru nanoclusters prepared by Ru 3(CO) 12 deposition on Au(1 1 1)

The adsorption and decomposition of Ru 3(CO) 12 on Au(1 1 1) at several substrate temperatures have been investigated by TDS, XPS and STM. The adsorption of Ru 3(CO) 12 is molecular at 90 K. Heating the surface covered with Ru 3(CO) 12 leads to the desorption of CO over a wide range of temperatures, which implies the gradual decomposition of the carbonyl molecules. The decarbonylation is complete at around 500 K, leaving metallic Ru on the surface. Carbonyl molecules are partially decomposed after adsorption at room temperature, forming islands of nanosized clusters preferentially located at the elbow sites of the Au(1 1 1) herringbone reconstruction. The remaining CO molecules desorb upon surface heat treatment, which promotes the mobility of the nascent metallic Ru nanoclusters and results in the non-coalescing aggregation of the nanoclusters. A recommended preparation of Ru nanoclusters is to deposit Ru 3(CO) 12 on gold at a substrate temperature of 500 K. This allows a fine control of Ru nanocluster coverages and lower level of carbon contamination in the deposited layer.

Luminescence Properties of Tris(2,2‘-bipyridine)ruthenium(II) in Sol−Gel Systems of SiO2

The luminescence spectra and the lifetime of tris(2,2‘-bipyridine)ruthenium(II), Ru(bpy)32+, were studied in the sol−gel reaction system of tetramethoxysilane (TMOS) at room temperature. The luminescence peaks and lifetime were considerably altered by the nature of the sol−gel matrix. These findings are discussed in connection with adsorption of Ru(bpy)32+ on gels and lower temperature measurements at 77 K.

The chemical and photochemical reactions of metal carbonyl cluster compounds on solid surfaces

Abstract

Formation and chemical reactions of ruthenium tricarbonyls adsorbed on metal oxides. Use of chemical reactions as a method of surface structure determination

The adsorption of Ru(CO) 3 Cl 2 (THF) onto the surface of hydroxylated metal oxides yields one of two surface metal carbonyls depending on the metal oxide. Depending on the nature of the metal oxide, the surface species either retains or loses coordinated chloride

In situ synthesis of [HRu 3(CO) 11] − on the surface of hydroxylated aluminum oxide

The in situ synthesis of supported [HR 3(CO) 11] − on hydroxylated aluminum oxide from a mononuclear precursor is demonstrated. It is shown by infrared spectroscopy, reaction stoichiometry, and analysis of extracted products that adsorption of Ru(CO) 3Cl 2(THF) onto CATAPAL SB alumina gives initially Ru II(CO) 3(ads) which reacts further with CO to give the supported cluster anion, [HRu 3(CO) 11] −(ads), rapidly at 25°C.

Adsorption of microamounts of ruthenium on hydrous iron oxides

The adsorption of Ru on amorphous Fe(OH)3, α-Fe2O3 and Fe3O4 have been measured as a function of the pH and the time of aging. The adsoprtion of Ru increases markedly in the 3–5.5 pH range. At higher pH values, α-Fe2O3 shows different behaviour with respect to Ru adsorption. The influence of EDTA, citrate and oxalate on the adsorption of Ru on Fe3O4 has also been investigated. Possible mechanisms of the adsorption of Ru on hydrous iron oxides are discussed in the light of the results obtained in the course of this study and of those of other researchers.

Dihexadecyl Phosphate Vesicles: Difference in the Spectroscopic Properties of Tris(2,2′-bipyridine)ruthenium(II) Adsorbed on the Inner and Outer Surfaces

The visible absorption spectrum of tris (2,2′-bipyridine)ruthenium(II) [ Ru ( bpy )32+] adsorbed on the outer surface of dihexadecyl phosphate vesicles is indistinguishable from the spectrum of free Ru ( bpy )32+ in aqueous solution. By contrast, the absorption spectrum of Ru ( bpy )32+ that is entrapped in vesicles by adsorption on inner surfaces exhibits a red shift in its visible absorption peak, and the extinction coefficient for this peak is increased. The emission spectrum for outer-adsorbed Ru ( bpy )32+ is red-shifted whilst that for inner-adsorbed Ru ( bpy )32+ is blue-shifted, compared with the spectrum for free Ru ( bpy )32+ in solution. The excited state of Ru ( bpy )32+ was longer lived, and was much less sensitive to quenching by oxygen, when the complex was adsorbed on inner vesicle walls. The above spectral variations indicate that the adsorption of Ru ( bpy )32+ on inner surfaces occurs in a way which leads to more spatial restriction on Ru ( bpy )32+ ions than does adsorption on outer surfaces of the bilayer . This asymmetry may be due to differences in the packing of dihexadecyl phosphate molecules as well as in the ionic strength of inner and outer aqueous environments.