Dispersed Iron Nanoparticles Research Articles

Universal design of three-dimensional porous graphene-iron based promotors for kinetically rationalized lithium-sulfur chemistry

Lithium-sulfur (Li-S) batteries are widely deemed to be one of the most potential candidates for future secondary batteries because of their remarkable energy density. Nevertheless, notorious polysulfide shuttling and retarded sulfur reaction kinetics pose significant obstacles to the further application of Li-S batteries. While rationally designed highly active electrocatalysts can facilitate polysulfide conversion, the universal and scalable synthesis strategies need to be developed. Herein, a universal synthetic strategy to construct a series of three-dimensional (3D) porous graphene-iron (3DGr-Fe) based electrocatalysts involving 3DGr-FeP, 3DGr-Fe3C, and 3DGr-Fe3Se4 is exploited for manipulating the Li-S redox reactions. It has been observed that the implementation of a 3D porous Gr architecture leads to the well-designed conductive networks, while the uniformly dispersed iron nanoparticles introduce an abundance of active sites, fostering the lithium polysulfide conversion, thereby bolstering the overall electrochemical performance. The Li-S battery with the 3DGr-Fe based electrocatalyst exhibits remarkable capacity retention of 94.8% upon 100 times at 0.2 C. Moreover, the soft-packaged Li-S pouch cell based on such a 3DGr-Fe electrocatalyst delivers superior capacity of 1060.71 mA h g−1 and guarantees for the continuous 30 min work of fan toy. This investigation gives comprehensive insights into the design, synthesis, and mechanism of 3DGr-Fe based electrocatalysts with high activity toward efficient and durable Li-S batteries.

Highly selective recovery of rare earth elements from mining wastewater using phyto-synthesized biochar dispersed iron nanoparticles

Recovery of rare earth elements (REEs) from secondary sources such as mining wastewater has attracted much recent attention due to the rising global demand for REEs and the need to environmentally protect potentially contaminated mine sites. One significant issue it that most adsorbents proposed for removal and/or recovery of REEs are not generally selective for REEs. In this study, biochar dispersed iron nanoparticles synthesized using a plant extract (BC-FeNPs) were successfully used for the selective recovery of REEs from mining wastewater, where the Kd values were Nd(III) (918 mL∙g−1), Eu(III) (1253 mL∙g−1), Tb(III) (1119 mL∙g−1), Dy(III) (1032 mL∙g−1), Lu(III) (1898 mL∙g−1), compared to only 23.9 mL∙g−1 for Zn(II). The maximum adsorption efficiency of REEs for the composite was higher than the constituent parts being 88.4 % for BC-FeNPs, but only 8.72 % for biochar and 82.4 % for FeNPs, respectively. FTIR, XPS and Zeta potential analysis suggested that the observed selective adsorption of REEs, involved interactions of REEs with O and N, as well as ion-exchange with H+ from the biochar and capping layer, as well as electrostatic interactions. The desorption efficiency of bound REEs from BC-FeNPs was > 85 % when using acetic acid, and was attributed to efficient competitive ion exchange. Pearson correlation analysis further demonstrated that the adsorption mechanism included ion complexation, ion exchange and electrostatic adsorption, while the desorption mechanism was mainly via ion exchange. Overall, BC-FeNPs has significant potential to practically recover REEs from mining wastewater having demonstrated excellent reusability after five adsorption–desorption cycles.

Preparation and evaluation of iron nanoparticles embedded CNTs grown on ZSM-5 as catalysts for NO decomposition

Due to their high activity and selectivity, single-atoms based catalysts for oxygen removal and wastewater treatment have received enormous attentions in academia and industry. The present work sought to extend the single-atom catalyst concept to NO decomposition. A series of catalysts with highly dispersed iron nanoparticles embedded in carbon nanotubes grown on a ZSM-5 zeolite were prepared using an induced growth method, by pyrolysing melamine and ferric nitrate precursors impregnated on ZSM-5 at 900 °C. The catalysts were then tested for their catalytic activity in NO decomposition using a fixed-bed reactor operating at 300 °C and were shown to be able to completely decompose NO under the test conditions. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), BET, Raman and temperature-programmed oxidation (TPO) were used to study the effects of molar ratio of ferric nitrate to melamine on the active species, sample structures and NO decomposition mechanism. An increase in the molar ratio of melamine to iron nitrate led to an improvement to the dispersibility of iron nanoparticles and enhancement of NO decomposition. The use of ZSM-5 increased the dispersion of iron, thus enhancing the catalytic decomposition of NO. The characterisation of the used catalysts revealed that it was possible to regenerate the catalytic activity by doping and pyrolysing the deactivated catalysts with melamine, with no significant difference to that of the fresh catalysts.

Abstract 2437: Microfluidic device integrated with lipid nanoprobe for extracellular vesicle isolation toward non-invasive cancer diagnosis

Abstract Extracellular vesicles (EVs) can mediate intercellular communication by transferring cargo proteins and nucleic acids between cells. Recently, they have been demonstrated for potential value in cancer diagnostics and treatment monitoring. However, relevant clinical translation is mainly limited by technical challenges in EV isolation. We previously reported lipid nanoprobes, which is a nanomaterial system of labeling probe and capture probe. The labeling probe is constructed with a lipid molecule as the active component to label EVs rapidly and spontaneously with high efficiency, while the capture probe can isolate labeled EVs magnetically. Herein, we report on the development of a microfluidic device with integrated lipid nanoprobe for on-chip EV isolation towards instrument development for clinical translation. The nanostructured substrate of the device is integrated with a micromixer for one-step isolation of EVs from 1-ml plasma. We validated the device with plasma collected from pancreatic cancer patients, followed by DNA mutation detection of EV cargo. Size-tunable nanostructures are fabricated by patterning high-resolution iron thin films on fused silica substrates. By judicious thermal annealing, homogeneously dispersed iron nanoparticles are formed by fission and fusion on the substrate, which are served as a mask for silica dry-etching. Subsequently, selected lipid nanoprobes, which can instantaneously insert into lipid bilayers of EVs, are grafted onto the nanostructured substrate in a micromixer. This platform is verified first to isolate cultured cancer cell-derived EVs spiked-in plasma samples that emulated clinical samples. This platform is further applied to isolate EVs from pancreatic cancer patients’ plasma and identified KRASmutations in EV DNA with highly sensitive droplet digital PCR. Together, this platform enables rapid and efficient isolation of EVs from plasma specimens, and thus, holds great potential in clinical translation. Citation Format: Siyang Zheng, Yuan Wan, Mackenzie Maurer, Yi-Qiu Xia, Si-Jie Hao, Wen-Long Zhang, Nelson S. Yee. Microfluidic device integrated with lipid nanoprobe for extracellular vesicle isolation toward non-invasive cancer diagnosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2437.

In Ukrainian

Iron nanoparticles show great reactivity in the remediation of groundwater and soil or other environmental applications, however, the persistence and dispersion of iron nanoparticles need to be improved. In this study, palygorskite and hexadecyl trimethylammonium modified palygorskite were used to support iron nanoparticles. The electron microscopic study of the obtained materials is performed. Iron nanoparticles had a core–shell structure with the core being iron, and the shell consisting of iron (hydr)oxides were detected by X-ray diffraction patterns. The sorption of uranium(VI) and cobalt(II) ions from contaminated waters using nanodispersed reactive active material on the basis of modified surfactant of clay mineral were investigated. The reduction of U(VI) a nd Co(II) was highest with HDTMA-palygorskite/iron particles, followed by palygorskite/iron particles and free iron nanoparticles. It has been shown that the efficiency of removal of metal ions is substantially influenced by the pH of the aqueous medium, the content of surfactant and the amount of immobilized nanosized Fe 0 on the surface of the palygorskite. The influence of iron in the composite on its sorption properties was investigated. It has been found that the optimum content of Fe in the composite for the extraction of Co(II) and U(VI) ions from aqueous solutions is 10 % of the mass of the sorbent. The processes of aging of composites and loss of reactivity with respect to Co(II) ions are studied. The possibility of their use in the purification of groundwater with the use of modern environmental technologies is shown. It has been found that the composite sorbent exhibits the best sorption properties in relation to both uranium (VI) and cobalt (II) , rather than pure nanosized iron, due to the increase of its dispersion due to the decrease in the agglomeration of nanosized iron particles and the increase in the specific surface area of the modified specimens. The presence of organo-palygorskite apparently decreased the extent of aggregation and the size of the iron particles. The prospect of using composites based on palygorskite and organopalygorskite with a layer applied Fe 0 for the effective removal of heavy metal ions and radionuclides from aqueous media has been established.

Iron-loaded amine/thiol functionalized polyester fibers with high catalytic activities: a comparative study.

Dispersion of iron nanoparticles (Fe-NPs) was achieved on polyester fabrics (PET) before and after the incorporation of dendrimers (PAMAM), 3-(aminopropyl) triethoxysilane (APTES) or thioglycerol (SH). The catalytic activity of the resulting materials (PET-Fe, PET-PAMAM-Fe, PET-APTES-Fe and PET-SH-FE) was comparatively investigated in the degradation of 4-nitrophenol (4-NP) and methylene-blue (MB). Full characterization through diverse instrumental methods allowed correlating the type of the organic moiety incorporated with the Fe content, catalytic properties and stability. The highest 4-NP degradation yield reached 99.6% in 12 min for PET-SH-Fe. The catalytic activity was explained in terms of reactant interaction with Fe-NPs. The 1st order reaction kinetics and pseudo-1st order adsorption kinetics provide evidence of the key role of reactant adsorption. These findings allow envisaging the preparation of fiber-based catalysts for potential uses in environmental and green chemistry.

Regulation of phosphorus bioavailability by iron nanoparticles in a monomictic lake

Dissolved reactive phosphorous (DRP) in lake systems is conventionally considered to predominate over other dissolved P species, however, this view neglects an important set of interactions that occurs between P and reactive iron hydroxide surfaces. This study addresses the coupling of P with dispersed iron nanoparticles in lakes, an interaction that may fundamentally alter the bioavailability of P to phytoplankton. We used diffusive gradients in thin films (DGT) and ultrafiltration to study Fe-P coupling in the water column of a monomictic lake over a hydrological year. Fe and P were predominantly colloidal (particle diameters > ~5 nm < ~20 nm) in both oxic epilimnetic and anaerobic hypolimnetic waters, but they were both DGT-labile under sub-oxic conditions, consistent with diffusion and dissolution of Fe-and-P-bearing colloids within the DGT diffusive gel. During peak stratification, increases in Fe and P bioavailability were spatially and temporally coincident with Fe nanoparticle dissolution and the formation of a deep chlorophyll maximum at 5–8 m depth. These results provide a window into the coupling and decoupling of P with mobile iron colloids, with implications for our understanding of the behaviour of nutrients and their influence on phytoplankton community dynamics.

Porous-Carbon-Confined Formation of Monodisperse Iron Nanoparticle Yolks toward Versatile Nanoreactors for Metal Extraction.

All-in-one architectures in which uniform nanoscale zero-valent iron nanoparticles are wrapped in hollow porous carbon shells are highly desirable for environmental applications such as wastewater treatment and for use as catalysts, but their preparation remains a significant challenge. Herein, a spatially confined strategy for the in situ preparation of uniform Fe0 @mC (mC=micro/mesoporous carbon) yolk-shell nanospheres, in which the iron nanoparticles are encapsulated in thin, porous carbon shells, is reported. The elaborately designed Fe0 @mC yolk-shell nanospheres were obtained by utilizing silica- and phenolic-resin-coated magnetite nanoparticle core-shell structures as templates by means of selective etching and in situ thermal reduction. The highly dispersed iron nanoparticles with superior reduction capability can effectively remove metal pollutants (e.g., AuIII , AgI , and CuII ), the carbon shell acts as protective cover and prevents aggregation of iron nanoparticles, and the void space in the capsules serves as a reactor for reduction and catalytic reactions.

Embedded iron nanoparticles by graphitized carbon as highly active yet stable catalyst for ammonia decomposition

The Fe nanoparticles embedded by graphitized carbon were developed through a strategy of hydrothermal and thermal treatment. The resulting materials, with high surface area and porosity, well dispersed iron nanoparticles (NPs) associated with graphitized carbon structure, show high activity and durability in ammonia decomposition reaction. Among the serial Fe-based catalysts, Fe@GC-4 of a low iron content (1.29wt%) exhibits significant ammonia decomposition activity (∼71% conversion and 22.1molH2 gFe−1h−1) at a gas hourly space velocity of 6000cm3gcat−1h−1 and 600°C. After an extended period of reaction conducted over the representative Fe@GC-3 catalyst, most of the embedded Fe NPs transform to nitride species with relatively smaller particle size, while the embedded structure still retains. This study provides new insights into the development of cheap metal-based catalysts functionalized by graphitized carbon (graphene) for the current reaction and other potential applications.

Embedded Iron Nanoparticles in Carbon Nanogranules for Direct Synthesis of Lower Olefins

AbstractIron nanoparticles in carbon nanogranules have been in‐situ generated during the synthesis of lower olefins from Syngas. Very uniformly distributed these carbon embedded iron nanoparticles are found to be very selective for the direct F−T synthesis of lower olefins. The iron incorporated carbon nanogranules were synthesized from refinery heavy residue/vacuum residue and ferrocene. The iron nanoparticles are sTable and do not undergo major sintering during the activity run. The HRTEM images show well dispersion of iron nanoparticles during reduction to reaction processes.

Degradation of chlorinated organic solvents in aqueous percarbonate system using zeolite supported nano zero valent iron (Z-nZVI) composite.

Chlorinated organic solvents (COSs) are extensively detected in contaminated soil and groundwater that pose long-term threats to human life and environment. In order to degrade COSs effectively, a novel catalytic composite of natural zeolite-supported nano zero valent iron (Z-nZVI) was synthesized in this study. The performance of Z-nZVI-catalyzed sodium percarbonate (SPC) in a heterogeneous Fenton-like system was investigated for the degradation of COSs such as 1,1,1-trichloroethane (1,1,1-TCA) and trichloroethylene (TCE). The surface characteristics and morphology of the Z-nZVI composite were tested using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Total pore volume, specific surface area, and pore size of the natural zeolite and the Z-nZVI composite were measured using Brunauer-Emmett-Teller (BET) method. SEM and TEM analysis showed significant elimination of aggregation and well dispersion of iron nano particles on the framework of natural zeolite. The BET N2 measurement analysis indicated that the surface area of the Z-nZVI composite was 72.3m(2)/g, much larger than that of the natural zeolite (0.61m(2)/g). For the contaminant analysis, the samples were extracted with n-hexane and analyzed through gas chromatograph. The degradation of 1,1,1-TCA and TCE in the Z-nZVI-catalyzed percarbonate system were 48 and 39% respectively, while strong augmentation was observed up to 83 and 99%, respectively, by adding the reducing agent (RA), hydroxyl amine (NH2OH•HCl). Probe tests validated the presence of OH(●) and O2 (●-) which were responsible for 1,1,1-TCA and TCE degradation, whereas both free radicals were strengthened with the addition of RA. In conclusion, the Z-nZVI/SPC oxidation with reducing agent shows potential technique for degradation of groundwater contaminated by 1,1,1-TCA and TCE.

Palladium complex immobilized on graphene oxide–magnetic nanoparticle composites for ester synthesis by aerobic oxidative esterification of alcohols

A well dispersed magnetically separable palladium complex immobilized to magnetite–graphene oxide nanocomposite has been synthesized via solvothermal route. The successfully decorated graphene oxide sheets with the homogeneously dispersed iron nanoparticles and palladium(II) complex were proved by transmission electron microscopy. X-ray diffraction pattern of the synthesized catalyst revealed that palladium(II) complex was successfully immobilized to the support. Further, X-ray photoelectron spectroscopy confirmed that palladium is present in +2 oxidation state. The synthesized heterogeneous material was found to be an efficient catalyst for the oxidative esterification of alcohols with methanol by using molecular oxygen as oxidant. The developed catalyst was found to be more reactive than its homogeneous analog, i.e. PdCl2(CH3CN)2. Similarly, no reaction occurred in the presence of Pd(0)/magnetite–graphene nanocomposite catalyst. These studies confirmed that the palladium(II) ions are the main catalyst and superior reactivity of heterogeneous palladium catalyst is attributed to the promotion role of graphene support in the adsorption of reactant alcohol and oxygen. After the reaction, the catalyst was easily separated by external magnetic effect and reused for several runs with consistent catalytic activity without any detectable leaching.

High throughput detection and selective enrichment of histidine-tagged enzymes with Ni-doped magnetic mesoporous silica.

This work reports a simple and facile method to prepare novel magnetic mesoporous silica (MMS) materials with high magnetic strength for the convenient and high throughput detection of histidine-tagged enzymes with Ni-doped surfaces. These materials are designed by the incorporation of high-abundance and homogeneously dispersed iron nanoparticles within the mesopores by thermal hydrogen reduction after the incorporation of ferrous ions and demonstrated the selective enrichment and high-throughput recognition of His-tagged enzymes with multi-point anchoring by selective conjugation between the His-tag and Ni ions. Selective His-tagged enzyme enrichment efficiency was compared with nickel-based MMS materials, such as Ni2+-MMS and Ni-MMS, and nickel ion doped silica-coated magnetic nanoparticles (Ni2+-MNPs). The efficiency was calculated to be 100 ± 1.93%, 70.94 ± 1.95%, and 37.03 ± 5.93% for Ni2+-MMS, Ni-MMS, and Ni2+-MNPs, respectively. This method enables a high-throughput and advanced systematic approach for the separation and immobilization of proteins which cover a broad spectrum of polyhistidine-tagged proteins.

Catalytic decomposition of nitrogen-containing heterocyclic compounds with highly dispersed iron nanoparticles on carbons

Decomposition of pyrrole or pyridine with iron catalysts supported on carbons has been studied with a cylindrical quartz-made pulse reactor, into which liquid pyrrole or pyridine is injected as a pulse, in order to develop a novel hot gas cleanup method of removing the nitrogen present in tar as N2. The catalyst is mainly prepared by heating FeOOH precipitated onto powdery cellulose from FeCl3 solution. Nanoscale iron catalysts with the average particle sizes of 25–30nm can promote decomposition reactions of the N-containing heterocyclic compounds in inert gas at >500°C and provide N2 yields of 40–45% after the almost complete decomposition of pyrrole at 600°C or pyridine at 650–700°C. Iron catalyst with the mean size of 100–500nm, prepared from Fe(NO3)3 impregnated with a commercial activated carbon, is also active for the decomposition of the heterocyclic N-compounds, but it is almost inactive for N2 formation, the yields being as low as less than 2% in all cases. The increase in the number of pulses lowers the catalytic activity of iron nanoparticles for N2 formation, whereas in situ H2 treatment at 500°C after reaction can restore it to the almost original state. On the basis of the above-mentioned results, it is likely that the activity of iron catalyst for N2 formation from pyrrole or pyridine is very sensitive to the iron particle size, and the in situ H2 treatment is effective for recovery of the decreased catalytic performance.

Onion-like nanoparticles with γ-Fe core surrounded by a α-Fe/Fe-oxide double shell

Using a low cost and simple chemical procedure, randomly dispersed iron nanoparticles (NPs) embedded in an activated carbon matrix were synthesized. The Fe-NPs exhibit an onion-like morphology that consists on a γ-Fe core surrounded by a double α-Fe (inner)/γ-Fe 2O 3 (outer) shells. The room temperature saturation magnetization value of the Fe-NPs is lower than that of bulk α-Fe as a consequence of the disordered interfacial spins. In addition, the broadening of the low temperature Mössbauer singlet contribution of the γ-Fe phase, seems to suggest a possible magnetic ordering of the core.

Preparation and X-ray visibility evaluation of radiopacity enhanced silicone rubber by ironic nanopartides

Objective To explore the feasibility of iron nanoparticles as radiopaque agents for modifying medical silicone rubber and to evaluate image visibility of modified materials.Methods Methyl vinyl silicone elastomer was mixed with iron nanoparticles,carbon-coated ferric nanoparticles,respectively,in accordance with the designed formula ratios.The composites were blended,mixed,molded and vulcanized with.Two groups of new materials,iron nanoparticle enhanced silicone rubber （INESR,Group1） and carbon-coated ferric nanoparticle enhanced silicone rubber（Fe/CESR,Group2）,were harvested.Medical silicone rubber was as a negative control group.CT scanning of each group of material samples in vitro was performed,and both CT images and measured CT values were collected.Differences in CT mean values between the groups were compared.Samples of new material groups were implanted subcutaneously in a dog and standardized radiographic images were obtained.X-Ray Diffraction was used to analyze the component stability of iron nanoparticles dispersing in the silicone rubber.Results Two groups of radiographic image enhanced silicone rubber were prepared.The X-ray images of new composites were clearly visible both in vitro and in vivo.CT values were increased with the increase of added metal nanoparticles and metal atomic weight.CT mean values of each group and the materials in Group 1 and Group2 with the same material formulation were significantly different （P〈0.001）.After placed for 180 days,the diffraction peak positions of elemental iron in both groups of materials remained essentially unchanged,and it showed that dispersed iron nanoparticles and carbon-coated iron nanopaarticles in silicone rubber were stable.Conclusion The metal nanoparticles of iron and carbon-coated ferrum can be used as radiographic markers for improving quality of X-Ray image of the medical silicone rubber. Key words: Biomaterials; Metal nanoparticles; Radiopacity; Silicone rubber

Synthesis and characterization of organo-montmorillonite supported iron nanoparticles

Iron nanoparticles show great reactivity in the remediation of groundwater and soil or other environmental applications, however, the persistence and dispersion of iron nanoparticles need to be improved. In this study, environment-friendly montmorillonite (Mont) and hexadecyl trimethylammonium modified montmorillonite (HDTMA-Mont) were used to support iron nanoparticles (denoted as Mont/iron and HDTMA-Mont/iron particles). The specific surface areas of the supported iron nanoparticles were 28.7 m 2/g and 38.1 m 2/g, while for unsupported nanoparticles 24.3 m 2/g. The presence of organo-montmorillonite apparently decreased the extent of aggregation and the size of the iron particles. Iron and crystalline iron oxide were detected by X-ray diffraction (XRD) patterns. In the Fourier Transform Infrared spectrum, CH 2 groups were present in HDTMA-Mont but not found in HDTMA-Mont/iron particles. From the results of X-ray photoelectron spectroscopy (XPS), iron nanoparticles had a core–shell structure with the core being iron, and the shell consisting of iron (hydr)oxides. In contact with Cr(VI), the reduction of Cr(VI) was highest with HDTMA-Mont/iron particles, followed by Mont/iron particles and free iron nanoparticles.

Dispersion of iron nano-particles on expanded graphite for the shielding of electromagnetic radiation

Abstract Composite materials containing electrically conductive expanded graphite (EG) and magnetic iron nano-particles for electromagnetic shielding were prepared by impregnating EG with an ethanol solution containing iron nitrate and acetic acid, followed by drying and reduction in H 2 . Magnetic nano-iron particles were found to be highly dispersed on the surface of EG in the Fe/EG composites, and played the role of enhancing the electromagnetic shielding effectiveness (SE) at low frequencies (0.3–10 MHz), which seemed to depend proportionally on magnetic hysteresis loss of loaded iron nano-particles.

Experimental study of the temperature dependence of the permittivity of nanocomposite materials based on a low-density polyethylene matrix with iron nanoparticles

The temperature dependence of the dielectric permittivity of nanocomposites based on a high-pressure (low-density) polyethylene matrix with various concentrations of dispersed iron nanoparticles (2–22 wt %) has been studied. As the temperature increases from 0 to 40°C, the permittivity decreases for all concentrations of nanoparticles in the range studied. The results can be useful for developing thermostable acoustic waveguides.

Iron and Ruthenium Nanoparticles in Carbon Prepared by Thermolysis of Buckymetallocenes

Thermolysis of fullerene iron and ruthenium complexes (buckymetallocene M(C(60)R(5))Cp (M = Fe; R = Ph (1) and Me (2), M = Ru; R = Ph (3), Me (4)) under a nitrogen atmosphere produced metal nanoparticles dispersed in carbon materials. The thermal degradation processes of the buckymetallocenes were studied by TG-DTA, TEM with a heating sample stage, and VT-XRD. Variation of the thermolysis temperature led to a change in the size of the nanoparticles and the morphology of the carbon materials. Thermolysis of buckyferrocene at 700 degrees C gave highly dispersed iron nanoparticles (average diameter of 7.4 nm). After thermal treatment at 900 degrees C, graphite structures such as carbon nanocapsules and carbon nanotubes formed because of the catalytic activity of the iron nanoparticles. Ruthenium nanoparticles prepared from buckyruthenocene were much smaller than the iron counterparts, and did not catalyze the formation of graphite structures. When buckyruthenocene absorbed on silica gel was heated at 500 degrees C under a hydrogen atmosphere, the resulting ruthenium nanoparticles showed high activity in catalytic hydrogenation.