Metal-containing Components Research Articles

Evolution of Organometallasiloxanes

The development of organometallasiloxane chemistry from first polymeric systems to individual organometallasiloxanes and functional oligomeric compounds is considered. The structural diversity of organosilicon precursors and the variability of metal-containing components are presented. Synthetic approaches are considered in detail, including those that allow targeted production of organometallasiloxanes of a certain structure. Using the example of organometallasiloxanes synthesized from trifunctional organoalkoxysilanes, methods for the synthesis of unique stereoregular functional cyclosiloxanes and their derivatives are highlighted. Considerable attention is given to the applied aspects of various structure organometallasiloxanes and their derivatives. The state of the art of the chemistry of organometallasiloxanes and their further evolution are evaluated critically.

Improving the efficiency of steelmaking slag processing at PJSC “MMK”

This paper assesses the efficiency of metallurgical slag processing at PJSC “MMK” in LLC “Slagservice”, which indicates the need to improve it in terms of increasing the degree of extraction of iron from slag. Proposals for improving the existing technology of steelmaking slag processing and the development of new technologies have been developed. An assessment of the efficiency of the metallurgical slag recycling at LLC “Slakservice” in 2019 is given. Ways to improve the efficiency of steelmaking slag processing in the conditions of existing production are presented. The description of the experimental setup for testing the basic principles of the proposed technology is given. The method of metallurgical slag processing was used in laboratory conditions, it corresponds to the existing technology of metallurgical slag processing in LLC “Slakservice”, including slag crushing, classification by size, metal separation by screening and magnetic separation.It is established that the method of separation of slag-metal conglomerate can be used in industrial conditions. The method of assessing the efficiency of metallurgical slag processing through the degree of extraction of metal-containing components from the slag was used for processing the results. A method of improving the existing technology of steelmaking slag processing is proposed, which includes increasing the content of metallic iron in the current converter slag by means of liquid-phase reduction of iron oxides using coal. The method of increasing the content of metallic iron in the current BOF slag in slag bowls using movable reactors is proposed. This method makes it possible to increase the content of metallic iron in the current BOF slag by about two times, which contributes to increasing the efficiency of magnetic separation at the stage of secondary slag processing.

ЗАСТОСУВАННЯ ГІДРОАКУСТИЧНИХ МЕТОДІВ ПІД ЧАС ГЕОХІМІЧНИХ ДОСЛІДЖЕНЬ РОЗПОДІЛУ ЗАБРУДНЮВАЧІВ У ПОВЕРХНЕВОМУ ШАРІ ДОННИХ ВІДКЛАДІВ

The article presents the results obtained during the long-term field studies of the characteristics of the sedimentary matter metal-containing component distribution within the territories of industrial cities, in particular, Zaporizhia city. Based on field contact and remote studies, one of the aspects of the problem was studied, namely the peculiarities of iron concentrations distribution in the surface layer of bottom sediments of the Dnipro river. Key practical approaches to the application of a new complex method of field observations are outlined, which combine the possibilities of express planar surveying with the determination of geochemical characteristics of river sediments. The methodology of combining contact geochemical studies of iron distribution in surface bottom sediments with the performance of a side view of a remote route survey using sonar is substantiated. Herewith, the possibility of determining the lithological differences of the surface layer of bottom sediments under the conditions of determining the average concentrations of iron for the main material types of sediments is assumed. The results of two-year research based on the data of fieldwork revealed promising perspectives for the development of such a complex of observations in the case of systematization of the direction, additional testing of the technological component in various test areas of the water area, as well as the development of an appropriate methodological foundation.

Probing Heterogeneous Water Distributions within Fuel Cell Membranes Using Combined Neutron and X-Ray Tomography (NeXT)

Water management in a fuel cell is an essential prerequisite for achieving high cell performance, where sufficient water is required for membrane hydration while excess liquid water leads to undesired mass transport losses. Existing heterogeneity within the fuel cell, such as those created by flow-field lands and channels create three-dimensional (3-D) heterogeneity in water distribution within the fuel cell components, which may have long term effect on the durability of fuel cell components, such as the membrane (1). 3-D visualization techniques such as X-ray (1-4) and neutron (5) tomography are powerful in revealing the effect of the existing heterogeneity on water distributions in 3-D. However, there is an opportunity to combine neutron and X-ray tomography (6) to probe into the details of these heterogenous water distributions even further and clarify their impacts on 3-D membrane hydration. In this study, we investigate the effect of heterogeneity in fuel cells (primarily land-channel heterogeneity) on 3-D membrane hydration and membrane morphology changes during fuel cell operation using simultaneous neutron and X-ray tomography (NeXT). The fuel cell is tested at varying gas humidity conditions in a serpentine flow-field configuration. A simultaneous coupling of neutron and X-ray imaging provides high contrast across various components of the fuel cell. Specifically, neutrons are highly attenuated by hydrogen atoms; hence neutron imaging is used to accurately locate and quantify operando water distribution. X-rays are sensitive to metals; hence simultaneous X-rays imaging is used to track metal-containing components (metal flow-field) and interfaces (such as interface between Pt-containing catalyst layer and membrane). This study demonstrates how heterogeneity in fuel cells plays a role in 3-D membrane hydration and needs to be tailored to enhance cell performance. References Y. Singh, R. T. White, M. Najm, T. Haddow, V. Pan, F. P. Orfino, M. Dutta, and E. Kjeang, J. Power Sources., 412 (2019): 224-237. Y. Nagai, J. Eller, T. Hatanaka, S. Yamaguchi, S. Kato, A. Kato, F. Marone, H. Xu and F. N. Büchi, J. Power Sources., 435 (2019). S. J. Normile, D. C. Sabarirajan, O. Calzada, V. De Andrade, X. Xiao, P. Mandal, D. Y. Parkinson, A. Serov, P. Atanassov and I. V. Zenyuk, Meter. Today Energy., 9 (2018). S. S. Alrwashdeh, I. Manke, H. Markötter, M. Klages, M. Göbel, J. Haußmann, J. Scholta and J. Banhart, ACS Nano., 11, 6 (2017). J. M. LaManna, Y. Yue, T. A. Trabold, J. D. Fairweather, D. S. Hussey, E. Baltic and D. L. Jacobson, Meet. Abstr. - Electrochem. Soc., 32 (2017). J. M. LaManna, D. S. Hussey, E. Baltic and D. L. Jacobson, Rev. Sci. Instrum., 88, 11 (2017).

Mild sulphuric acid pre-treatment for metals removal from biosolids and the fate of metals in the treated biosolids derived biochar

Biosolids are contaminated with heavy metals (HMs) and alkali and alkaline earth metals (AAEMs). These metals limit the suitability of biosolids for land application as well as their pyrolytic conversion to high-quality products. In this work, a mild sulphuric acid pre-treatment of biosolids was carried out at different stirring speeds (300–900 rpm), temperatures (25–100 °C), extraction time (0–180 min), and acid concentration (1–5% v/v) to reduce the metals load in biosolids and their biochar derived from pyrolysis. The metal leaching process was very rapid and reached equilibrium in less than 30 min. The optimum conditions removed about 75–95% HMs and 80–95% AAEMs except Ca due to the formation of CaSO4 hydrates. Temperature was the driving parameter for Cd and Ni extraction, whereas temperature and acid concentration played the leading roles in Cu extraction. The shrinking core product layer diffusion and surface chemical reaction models described the extraction kinetics of Ni, Cu and Cd. A leaching activation energy of 10.02 kJ/mol and 7.37 kJ/mol was estimated for Ni and Cd, respectively. FTIR, SEM and XRD characterisation of the treated biosolids jointly indicated that the leaching mechanism was dominated by acid dissolution of metal-containing components followed by ion exchange of metal species with protons from H2SO4. Treatment at 25 °C and 3% H2SO4 lowered the biosolids ash content by 50% and preserved the physicochemical attributes, which enhanced the pyrolysis upcycling of the treated biosolids. Pre-treatment influenced the migration characteristics of the metals during pyrolysis and the produced biochar had several folds lower HMs and AAEMs contents than the raw biosolids-derived biochar.

Unlocking the computational design of metal-organic cages.

Metal–organic cages are macrocyclic structures that can possess an intrinsic void that can hold molecules for encapsulation, adsorption, sensing, and catalysis applications. As metal–organic cages may be comprised from nearly any combination of organic and metal-containing components, cages can form with diverse shapes and sizes, allowing for tuning toward targeted properties. Therefore, their near-infinite design space is almost impossible to explore through experimentation alone and computational design can play a crucial role in exploring new systems. Although high-throughput computational design and screening workflows have long been known as powerful tools in drug and materials discovery, their application in exploring metal–organic cages is more recent. We show examples of structure prediction and host–guest/catalytic property evaluation of metal–organic cages. These examples are facilitated by advances in methods that handle metal-containing systems with improved accuracy and are the beginning of the development of automated cage design workflows. We finally outline a scope for how high-throughput computational methods can assist and drive experimental decisions as the field pushes toward functional and complex metal–organic cages. In particular, we highlight the importance of considering realistic, flexible systems.

Bioanalytical applications of Mössbauer spectroscopy

Data on the applications of Mössbauer spectroscopy in the transmission (mainly on 57Fe nuclei) and emission (on 57Co nuclei) variants for analytical studies at the molecular level of metal-containing components in a wide range of biological objects (from biocomplexes and biomacromolecules to supramolecular structures, cells, tissues and organisms) and of objects that are participants or products of biological processes, published in the last 15 years are discussed and systematized. The prospects of the technique in its biological applications, including the developing fields (emission variant, use of synchrotron radiation), are formulated.The bibliography includes 248 references.

A Device to Drive CFL Bulbs with Busted Electronic Ballast: A Prototype Development and Evaluation

CFLs are one of the most commonly used lighting fixtures in the modern era. Studies regarding its life cycle assessment (LCA) indicated that in the disposal stage CFLs have more hazardous potential to impact human health and ecosystem than the incandescent bulbs due to their higher metal-containing components. Thus, possible recycling of CFL bulbs with busted electronic ballast but still has its remaining life span should considered. By using experimental-developmental method, the study aimed to develop a prototype device to drive CFL bulbs with busted electronic ballast. The prototype was tested and evaluated regarding its efficiency as compared to original electronic ballast of CFLs. Results indicated that the developed prototype had efficiencies ranging from 75.6% to 90.8% respectively. Statistical tests also indicated that though found out to have numerical difference between the illuminations emitted by the lamp when driven by its original electronic ballast to the illumination it emits when driven by the prototype device, this numerical difference would not translate into a significant statistical difference.

IR Study of Fe and Ni Nanoscale Particles in the Carbon Dioxide Reforming of Lignin

Structural changes in lignin whose surface is modified with nanoscale nickel and iron-containing particles are studied via vibrational spectroscopy during the reforming of carbon dioxide, stimulated with microwave radiation. It is shown that vanillic acid is transformed into synthesis gas upon convective heating if there are conditions for its existence in monomeric form. The applied metal-containing components greatly alter the structural characteristics of lignin. An internal standard shows that nickel deposited on the surface of lignin from an acetate salt aqueous solution reacts with surface aldehyde groups to oxidize them into carboxylate ones. IR data obtained in situ inside a catalytic cell show that the decomposition of lignin in the presence of nanoscale nickel-containing particles in a CO2 environment during convective heating yields vanillin derivatives (acid and alcohol) that are firmly anchored on the surface of the material by hydrogen bonds. Nanoscale iron particles deposited on a surface of acetylacetonate complex are strongly coordinated on alkoxy groups of lignin. The organic matter of lignin decomposes during convective heating in CO2 to form light products (hydrocarbons and oxygenates).

Reply to the Letter to the Editor: Is There a Cardiotoxicity Associated With Metallic Head Hip Prostheses? A Cohort Study in the French National Health Insurance Databases.

To the Editor, We thank Drs. Matharu and Whitehouse for their interest in our research [2] and for their valuable contribution. Although we appreciate their comments, we would like to make the following clarifications. As a reminder, the main objective of our study was to assess the risk of dilated cardiomyopathy or heart failure specifically associated with metallic versus nonmetallic head THA using data from the French national health insurance databases. In their first comment, Drs. Matharu and Whitehouse argue that because THA stems contain metal, not accounting for stem material in these THAs may have caused substantial residual confounding. We agree that all of the THA metal-containing components should be considered in order to properly quantify a potential role of THA metal overall. In our study, because information on stem material was not available and therefore could not be accounted for, the magnitude of the overall association between THA metal and the risk of dilated cardiomyopathy or heart failure may have been underestimated. However, since all THA stems are made of metal (most commonly cobalt chrome or titanium), and since there is no particular reason to believe that one head material (ceramic or metal) is more likely to be used with one of those stem materials, it seems unlikely to us that stem material would cause residual confounding. Another critique relates to the lack of a control group of individuals without THA. We agree that such a control group would be of interest to assess the cardiovascular risks associated with THA. However, it turns out that osteoarthritis is itself a cardiovascular risk factor [1] independent of the presence or absence of a THA, and so estimating the proper role of THA characteristics in explaining an increased risk in patients with versus without THA would require accounting for detailed information on individual osteoarthritis diagnosis and severity. Unfortunately, such information is not available in the French national health insurance databases. In our study, we compared the risk between patients with metallic versus nonmetallic head THAs. Regarding osteoarthritis diagnosis and severity, the two groups were a priori comparable after adjusting for major other cardiovascular risk factors. Such a design was the most appropriate to adequately answer the question of a potential role of metallic versus nonmetallic head THA in increasing the risk of dilated cardiomyopathy or heart failure. Lastly, we agree with Drs. Matharu and Whitehouse’s point stating that, in addition to our study focusing on morbidity outcomes, further studies considering cause-specific mortality would be of interest to assess the cardiovascular risks of metallic head THAs in more detail.

57Fe-Mössbauer spectroscopy and electrochemical activities of graphitic layer encapsulated iron electrocatalysts for the oxygen reduction reaction

Graphitic layer encapsulated iron based nanoparticles (G@FeNPs) have recently been disclosed as an interesting type of highly active electrocatalysts for the oxygen reduction reaction (ORR). However, the complex composition of the metal-containing components and their contributions in catalysis remain unclear. As a representative catalyst of the unique encapsulated structure, a series of G@FeNPs catalysts were prepared by a high-pressure pyrolytic process with uniform and essentially identical morphologies but varied compositions. The catalysts exhibited a high onset potential of 0.85V at 0.1mAcm−2 in acidic media. By 57Fe-Mössbauer spectroscopy the iron containing components were identified including α-Fe, γ-Fe, γ-Fe2O3, and Fe3C as well as a minor doublet component due to Fe3+ in high spin and/or Fe2+ in low spin state. The ORR activities are evaluated in terms of the mass specific kinetic current density found to be positively correlated with the Fe3C content in the range of study, indicating involvement of the encapsulated nanoparticles in the ORR catalysis. The recognition of the Fe compositions and active sites provides new insights to the confined Fe-based ORR electrocatalysts and therefore options for further development of non-precious metal materials.

Pristine but metal-rich Río Sucio (Dirty River) is dominated by Gallionella and other iron-sulfur oxidizing microbes.

Whether the extreme conditions of acidity and heavy metal pollution of streams and rivers originating in pyritic formations are caused primarily by mining activities or by natural activities of metal-oxidizing microbes living within the geological formations is a subject of considerable controversy. Most microbiological studies of such waters have so far focused on acid mine drainage sites, which are heavily human-impacted environments, so it has been problematic to eliminate the human factor in the question of the origin of the key metal compounds. We have studied the physico-chemistry and microbiology of the Río Sucio in the Braulio Carrillo National Park of Costa Rica, 22km from its volcanic rock origin. Neither the remote origin, nor the length of the river to the sampling site, have experienced human activity and are thus pristine. The river water had a characteristic brownish-yellow color due to high iron-dominated minerals, was slightly acidic, and rich in chemolithoautotrophic iron- and sulfur-oxidizing bacteria, dominated by Gallionella spp. Río Sucio is thus a natural acid-rock drainage system whose metal-containing components are derived primarily from microbial activities.

The emerging role of lysosomes in copper homeostasis.

The lysosomal system operates as a focal point where a number of important physiological processes such as endocytosis, autophagy and nutrient sensing converge. One of the key functions of lysosomes consists of regulating the metabolism/homeostasis of metals. Metal-containing components are carried to the lysosome through incoming membrane flows, while numerous transporters allow metal ions to move across the lysosome membrane. These properties enable lysosomes to direct metal fluxes to the sites where metal ions are either used by cellular components or sequestered. Copper belongs to a group of metals that are essential for the activity of vitally important enzymes, although it is toxic when in excess. Thus, copper uptake, supply and intracellular compartmentalization have to be tightly regulated. An increasing number of publications have indicated that these processes involve lysosomes. Here we review studies that reveal the expanding role of the lysosomal system as a hub for the control of Cu homeostasis and for the regulation of key Cu-dependent processes in health and disease.

Heterodinuclear (Sm, Tb) lanthanide pivalates with heterocyclic N-donors: synthesis, structure, thermal behavior, and magnetic and photoluminescence properties.

Heterobimetallic complexes [SmTb(piv)6(phen)2] (1), [SmTb(piv)6(bath)2]·1.75EtOH (2a·1.75EtOH), [SmTb(piv)6(bath)2]·2EtOH (2b·2EtOH), and [SmTb(piv)6(bath)2]·EtOH (2b·EtOH), where piv is (CH3)3CCO2(-), phen is 1,10-phenanthroline, and bath is 4,7-diphenyl-1,10-phenanthroline, were synthesized and studied by X-ray diffraction. It was shown that complexes 2a·1.75EtOH and 2b·2EtOH have different molecular and crystal structures. Complexes 2a·1.75EtOH, 2b·2EtOH, and 2b·EtOH differ in the structural functions of μ2-piv anions. 2a·1.75EtOH contains two μ2-piv-κ(2)O,O' anions and two μ2-piv-κ(2)O,O,O' anions, whereas 2b·2EtOH and 2b·EtOH have four μ2-piv-κ(2)O,O' anions. According to the mass spectrometry data, the dimeric molecule [SmTb(piv)6] is the major metal-containing component of gas-phase complexes 1, 2a·1.75EtOH, and 2b·2EtOH. The characteristic features of the thermal behavior of these complexes were revealed, and their magnetic and photoluminescence (PL) properties were investigated. A unique feature of desolvated complexes 2a·1.75EtOH and 2b·2EtOH is melting at high temperatures before thermal decomposition. The magnetic properties of 1 and 2a·1.75EtOH are determined mainly by the Tb(3+) ions. The optical properties of these complexes and their homodinuclear analogs were analyzed by photoluminescence, excitation, phosphorescence, and scattering spectroscopy and by lifetime measurements at 77 K and 300 K. As the temperature decreases to 77 K, the PL intensity of Tb(3+) ions in 1 and 2a·1.75EtOH substantially increases by 40 and 100 times, respectively, compared to 300 K. The PL color evidently changes from red at 300 K to bright green at 77 K. Based on these results, the mechanism of intramolecular energy transfer between the ligand levels and Sm(3+) and Tb(3+) ions under UV radiation was proposed.

Potential Environmental Impacts from the Metals in Incandescent, Compact Fluorescent Lamp (CFL), and Light-Emitting Diode (LED) Bulbs

Artificial lighting systems are transitioning from incandescent to compact fluorescent lamp (CFL) and light-emitting diode (LED) bulbs in response to the U.S. Energy Independence and Security Act and the EU Ecodesign Directive, which leads to energy savings and reduced greenhouse gas emissions. Although CFLs and LEDs are more energy-efficient than incandescent bulbs, they require more metal-containing components. There is uncertainty about the potential environmental impacts of these components and whether special provisions must be made for their disposal at the end of useful life. Therefore, the objective of this study is to analyze the resource depletion and toxicity potentials from the metals in incandescent, CFL, and LED bulbs to complement the development of sustainable energy policy. We assessed the potentials by examining whether the lighting products are to be categorized as hazardous waste under existing U.S. federal and California state regulations and by applying life cycle impact-based and hazard-based assessment methods (note that "life cycle impact-based method" does not mean a general life cycle assessment (LCA) but rather the elements in LCA used to quantify toxicity potentials). We discovered that both CFL and LED bulbs are categorized as hazardous, due to excessive levels of lead (Pb) leachability (132 and 44 mg/L, respectively; regulatory limit: 5) and the high contents of copper (111,000 and 31,600 mg/kg, respectively; limit: 2500), lead (3860 mg/kg for the CFL bulb; limit: 1000), and zinc (34,500 mg/kg for the CFL bulb; limit: 5000), while the incandescent bulb is not hazardous (note that the results for CFL bulbs excluded mercury vapor not captured during sample preparation). The CFLs and LEDs have higher resource depletion and toxicity potentials than the incandescent bulb due primarily to their high aluminum, copper, gold, lead, silver, and zinc. Comparing the bulbs on an equivalent quantity basis with respect to the expected lifetimes of the bulbs, the CFLs and LEDs have 3-26 and 2-3 times higher potential impacts than the incandescent bulb, respectively. We conclude that in addition to enhancing energy efficiency, conservation and sustainability policies should focus on the development of technologies that reduce the content of hazardous and rare metals in lighting products without compromising their performance and useful lifespan.

Synthesis and properties of nanocomposites based on magnetite and biocompatible polymers

Magnetosensitive composites were prepared on the basis of biocompatible polymers using Elmore reaction. The structure of the composites and the morphology of the metal-containing component were examined. The magnetic characteristics of the materials were studied.

Nanosized Zinc Oxide Particles and Binary Layered Metal Hydroxides as Effective Components of Flame-retarding Systems for Plasticised Polyvinyl Chloride

In the present work, investigations were made of the efficiency of the heat-stabilising effect of new flame-retardant systems using nanosized metal-containing components with the aim of producing materials of reduced flammability, smoking capacity, and breakdown-product toxicity. As a result of the conducted investigations it was established that the best fireproofing characteristics are possessed by a PVC composite containing ammonium salt of amino-tris-methylene phosphonic acid and zinc oxide with 50 nm particles. The oxygen index of the indicated composite was 27.5%.

Imaging Metals in Proteins by Combining Electrophoresis with Rapid X-ray Fluorescence Mapping

Growing evidence points toward a very dynamic role for metals in biology. This suggests that physiological circumstance may mandate metal ion redistribution among ligands. This work addresses a critical need for technology that detects, identifies, and measures the metal-containing components of complex biological matrixes. We describe a direct, user-friendly approach for identifying and quantifying metal-protein adducts in complex samples using native- or SDS-PAGE, blotting, and rapid synchrotron X-ray fluorescence mapping with micro-XANES (X-ray absorption near-edge structure) of entire blots. The identification and quantification of each metal bound to a protein spot has been demonstrated, and the technique has been applied in two exemplary cases. In the first, the speciation of the in vitro binding of exogenous chromium to blood serum proteins was influenced markedly by both the oxidation state of chromium exposed to the serum proteins and the treatment conditions, which is of relevance to the biochemistry of Cr dietary supplements. In the second case, in vivo changes in endogenous metal speciation were examined to probe the influence of oxygen depletion on iron speciation in Shewanella oneidensis.

Combining metals with halogen bonds

Halogen bonds in the solid state have been investigated for many years, with a major resurgence in activity occurring in the past decade. The emphasis of most studies has been on organic components. This Highlight focusses on inorganic components, or at least metal-containing components, and explores their propensity to form halogen bonds. The use of C–X⋯X′–M halogen bonds in forming networks is briefly reviewed and their utility in investigating the nature of halogen bonds is explored since their strength can be tuned by changing either the organic (donor) halogen (C–X) or the inorganic (acceptor) halogen (M–X′). A survey has been performed of crystal structures in which interactions are of suitable geometry to be considered as halogen bonds. In particular the role of simple monatomic (e.g.oxo, nitrido) and diatomic (e.g.carbonyl, cyanide) ligands as halogen bond acceptors in transition metal complexes is examined. Main group metals are also considered in a further section that considers D–X⋯A–M halogen bonds, where D = halogen bond donor, A = halogen bond acceptor and M = main group metal or metalloid. Many examples presented herein were not identified as halogen bonds in the original articles. The aim of this survey is to examine the breadth of elements that can be involved in halogen bonding involving at least one inorganic (metal-containing) component and consider this range of interactions as a basis for future research in halogen bonding with applications in crystal engineering and allied areas.

Rapid preparation of Pt-Ru/graphitic carbon nanofiber nanocomposites as DMFC anode catalysts using microwave processing.

Pt-Ru/graphitic carbon nanofiber (GCNF) nanocomposites have been prepared on two different GCNF supports, with the use of a bimetallic precursor as a source of metal and microwave processing for thermal treatments. Pt-Ru nanoparticles appear as the major metal-containing component of these nanocomposites along with variable trace amounts of Ru metal. Use of microwave heating permits rapid preparation of these nanocomposites and affords metal nanoclusters of nearly uniform size. The performance of these nanocomposites as anode electrocatalysts in direct-methanol fuel cells (DMFCs) is compared with that of unsupported Pt-Ru colloid at identical total metal loading. The Pt-Ru/narrow tubular herringbone GCNF nanocomposite shows DMFC performance comparable to that recorded for an unsupported Pt-Ru colloid.