Transition Metal Contamination Research Articles

Metal-Free Activation of Molecular Oxygen by Quaternary Ammonium-Based Ionic Liquid: A Detail Mechanistic Study.

Most oxidation processes in common organic synthesis and chemical biology require transition metal catalysts or metalloenzymes. Herein, we report a detailed mechanistic study of a metal-free oxygen (O2) activation protocol on benzylamine/alcohols using simple quaternary alkylammonium-based ionic liquids to produce products such as amide, aldehyde, imine, and in some cases, even aromatized products. NMR and various control experiments established the product formation and reaction mechanism, which involved the conversion of molecular oxygen into a hydroperoxyl radical via a proton-coupled electron transfer process. Detection of hydrogen peroxide in the reaction medium using colorimetric analysis supported the proposed mechanism of oxygen activation. Furthermore, first-principles calculations using density functional theory (DFT) revealed that reaction coordinates and transition state spin densities have a unique spin conversion of triplet oxygen leading to formation of singlet products via a minimum energy crossing point. In addition to DFT, domain-based local pair natural orbital coupled cluster, (DLPNO-CCSD(T)), and complete active space self-consistent field, CASSCF(20,14) methods complemented the above findings. Partial density of states analysis showed stabilization of π* orbital of oxygen in the presence of ionic liquid, making it susceptible to hydrogen abstraction in a mild, metal-free condition. Inductively coupled plasma atomic emission spectroscopic (ICP-AES) analysis of reactant and ionic liquids clearly showed the absence of any significant transition metal contamination. The current results described the origin of O2 activation within the context of molecular orbital (MO) theory and opened up a new avenue for the use of ionic liquids as inexpensive, multifunctional and high-performance alternative to metal-based catalysts for O2 activation.

Asymmetric response of transition metal cationic orbitals to applied electric field

Understanding the quantum mechanical mechanisms underlying atomic/ionic interfacial processes and phenomena, particularly their dependence on the electronic orbital rearrangement of atoms/ions in an external electric field, remains a significant challenge. This study investigated the asymmetric response of transition metal (TM) cationic orbitals when subjected to an applied electric field. Quantum mechanical calculations were employed to quantify the newly formed hybrid orbitals and evaluate the corresponding orbital energies of the TM cations. Analysis of the quantitative contribution of asymmetric orbital hybridization to TM–surface interactions showed a significant change in orbital energy and increased effective charges of TM cations at the charged surface. This asymmetric response, induced by a negative external electric field generated from the structural charges of clay minerals (e.g., montmorillonite), repels electrons from the outer-shell orbital. This repulsion consequently increases the electron binding energy of the inner-shell orbitals, leading to new surface reactions, polarization-enhanced induction force, and polarization-induced covalent bonding between the TM cations and the charged surface. Our theoretical predictions regarding TM–clay mineral interactions are consistent with the experimental observations of TM cation adsorption. This finding has significant implications for the adsorptive removal of TM cations from wastewaters and for enhancing the catalytic efficiency of TM–surface catalysts. The unique physical and chemical characteristics exhibited by TMs at charged particle surfaces, resulting from their asymmetric response, can play pivotal roles in environmental and chemical engineering.

Treatment of mine water for the fast removal of zinc and lead by wood ash amended biochar

Lead and zinc mines are a primary source of environmental (post)-transition metal contamination resulting in major water pollution. Wood ash amended biochar has the potential to remediate mine contaminated water.

Occurrence and probabilistic health risk assessment (PRA) of dissolved metals in surface water sources in Southern Peru

Often, metal and metalloid ions are present in water at concentrations that seriously affect human health; understanding their occurrence is critical, especially in regions such as Peru, where natural volcanic activity and anthropogenic activity have made them more prevalent in local waterbodies. In this study, river, lake, aquifer, and irrigation water samples, collected from the Chili-Quilca, Camana-Majes, Colca-Chivay-Siguas, Ocoña, Urubamba-Vilcanota, and Titicaca river basins in Southern Peru, were analyzed for transition metals, other metals, metalloids, and other inorganic water constituents. Special emphasis was placed on metals and metalloids regulated by Peruvian Water Quality Standards and those categorized as of “primary interest” by the U.S. EPA, herein collectively referred to as “elements of concern”. Of the elements of concern, boron (2,170 µg L−1) and arsenic (2,060 µg L−1), were found at the highest concentrations in river water in the southern basins. Phosphorus (2,000 µg L−1) and boron (2,056 µg L−1) were found at the highest concentrations in irrigation water. The most frequently found elements of concern (in more than 60% of the samples) in all types of surface water samples were Al, As, B, Ba, Cu, Li, Mn, Sr, P, V and Zn. The most polluted waters, based on regulated metals concentrations and on their HQing quotient, followed the order: groundwater > river water > lake water. The potential sources of transition metal contamination were deduced by applying the multivariant statistical technique, principal component analysis (PCA), to the extensive sample dataset that included 35 variables and a total of 7,686 data of metal, metalloids, and other constituent concentrations, as well as physicochemical parameters. A Spanish translation of this paper is available in the online Supplementary Material.

N, S, P co-doped graphene-like carbon nanosheets developed via in situ engineering strategy of carbon pz-orbitals for highly efficient oxygen redox reaction

Multi-heteroatom doped carbon materials without any potential threat of transition metal contaminants are ideal candidates to replace precious metals for the electrocatalysis of energy conversion. However, tuning their bifunctionality for oxygen redox reaction (oxygen reduction reaction (ORR) and oxygen evolution reaction (OER)) is still a critical issue. Herein, N, S, P co-doped graphene-like carbon nanosheets (NSP/C) were developed via a bottom-up doping strategy with NaCl as template using a new precursor of N, S co-containing copolymer of 2, 6-Diacetylpyridine (DAP, N source) and 2-aminophenyl disulfide (APD, S source), and mixed with a P source of phosphonitrilic chloride trimer (PCT). The optimized NSP/C derived from DAP/APD and PCT with the mass ratio of 1:1 presents an ultra-high surface area of 1209 m2·g−1, around 3.0 nm in the thickness of nanosheets, resulting in a high half-wave potential up to 0.88 V vs. RHE for ORR and a low overpotential down to 0.35 V vs. RHE at 10 mA cm−2 for OER, as well as remarkable stability, while its overall oxygen redox activity is 0.70 V in 0.1 M KOH. And the performance was also proved by a practical rechargeable zinc-air battery with a maximum power density output of 156 mW·cm−2, which is better than that of the same-loading commercial catalysts of Pt/C and IrO2 (mixed with a mass ratio of 1:1). The high bifunctionality is strongly relied on the energy increase of pz-orbitals of carbon atoms in active sites comprising the specific ratio of graphitic N, thiophenic S and graphitic P dopants obtained from the new precursor.

Partitioning of transition metals during magnetization of oxidized pyrrhotite tailings

Low-temperature magnetization using reducing gas derived from biomass pyrolysis is being explored as an option to recover Fe from oxidized waste generated during Ni extraction from bio-leaching of pyrrhotite-rich tailings. The study investigates the potential sequestration of the main transition metal contaminants - Cu and Ni - into the magnetic phases. In the original oxidized pyrrhotite tailings, Ni and Cu were associated with goethite. Magnetization at 460 °C led to full conversion of goethite and jarosite into magnetite through solid-state transformation. 93% of the magnetite was recovered in the magnetic fraction by magnetic separation. Nickel and Cu accumulation was respectively 4 times and 2 times greater in the magnetic than nonmagnetic fraction, indicating that the magnetic fraction acted as a sink for these transition metals. Metal fractionation of the magnetic fraction showed that a greater proportion of total Ni resided with the crystalline and refractory phases compared to Cu (47% of total Ni vs. 29% of total Cu). The greater affinity for Ni to incorporate into magnetite was further demonstrated using magnetized goethites co-precipitated with 100 mmol Cu or Ni kg−1: most Ni was associated with the amorphous and crystalline Fe whereas 60% of total Cu was extracted as a sorbed/exchangeable species. The greater Cu mobility during sequential extraction of magnetite is likely attributable to its monovalent state in this reducing system. Low-temperature magnetization coupled with biomass pyrolysis may represent a viable option to manage iron and leftover transition metals in oxidized, (bio)leached pyrrhotite wastes as a way to produce much smaller volumes of inert wastes.

Cp2Mg-induced transition metal ion contamination and performance loss in MOCVD-grown blue emitting InGaN/GaN multiple quantum wells

The detrimental effects of Cp2Mg-induced trace transition metal (iron and manganese) contamination on the optical performance of metalorganic chemical vapor deposition (MOCVD)-grown blue-emitting InGaN/GaN multiple quantum wells (MQWs) are investigated experimentally. Five samples are grown at various stages of conditioning of a freshly installed MOCVD tool with stainless steel gas lines. Without conditioning, Cp2Mg flow induced Fe and Mn impurities with concentrations of 3×1015 and 3×1014 cm−3, respectively. These contaminants introduce nonradiative recombination centers with lifetimes on the order of nanoseconds. These impurities also induce indium-clustering related phenomena such as low energy shoulder at low temperature and a strong S-curve shift in emission energy with increasing temperature. Through successive cycles of chamber conditioning, the Fe and Mn concentrations decrease to below their detection limits, and the nonradiative recombination lifetime (+8 ns), internal quantum efficiency (+26%), microphotoluminescence nonuniformity (−4.7%), and S-curve shift (−26 meV) of the MQWs improved. The suppression of the transition metal ion contamination in the MOCVD chamber is shown to be crucial for high performance MQWs and blue light emitting diode growths.

Room-Temperature Organic Ferromagnetism

Reports of room-temperature organic ferromagnetism have faced widespread suspicion mostly because of shaky proposed mechanisms and transition-metal contamination. In this Chem issue, Wu and co-workers report a covalently linked organic radical framework in which the adjacent radicals interact to exhibit spontaneous magnetization at room temperature with the typical hysteresis of ferromagnets.

Moving Beyond p-Type mc-Si: Quantified Measurements of Iron Content and Lifetime of Iron-Rich Precipitates in n-Type Silicon

N-type multicrystalline silicon (mc-Si) is a promising alternative to the dominant p-type mc-Si for solar cells because it combines the cost advantages of mc-Si while benefiting from higher tolerance to transition metal contamination. A detailed understanding of the relative roles of point defect and precipitated transition metals has enabled advanced processing and high minority carrier lifetimes in p-type mc-Si. This contribution extends that fundamental understanding to Fe contamination in n-type mc-Si, helping enable processing of this material into an economical and high-performance photovoltaic device. By directly correlating micro-photoluminescence-based minority carrier lifetime mapping and synchrotron-based micro-X-ray fluorescence mapping of Fe-rich precipitates, we develop a quantitative, physical understanding of the recombination activity of Fe-rich precipitates in n - type mc-Si.

Highly efficient organic photocatalysts discovered via a computer-aided-design strategy for visible-light-driven atom transfer radical polymerization

Organocatalysed photoredox-mediated atom transfer radical polymerization (O-ATRP) is a very promising polymerization method as it eliminates concerns associated with transition-metal contamination of polymer products. However, reducing the amount of catalyst and expanding the monomer scope remain major challenges in O-ATRP. Herein, we report a systematic computer-aided-design strategy to identify powerful visible-light photoredox catalysts for O-ATRP. One of our discovered organic photoredox catalysts controls the polymerization of methyl methacrylate at sub-ppm catalyst loadings (0.5 ppm—a very meaningful amount enabling the direct use of polymers without a catalyst removal process); that is, 100–1,000 times lower loadings than other organic photoredox catalysts reported so far. Another organic photoredox catalyst with supra-reducing power in an excited state and high redox stability facilitates the challenging polymerization of the non-acrylic monomer styrene, which is not successful using existing photoredox catalysts. This work provides access to diverse challenging organic/polymer syntheses and makes O-ATRP viable for many industrial and biomedical applications. Organocatalysed photoredox-mediated atom transfer radical polymerization is a very promising method, although many challenges still lie ahead. Now, Kwon, Gierschner, Kim and co-workers present a computer-aided-design strategy to identify organic photoredox catalysts for this process. The success of the design strategy is demonstrated by polymerizations of methyl methacrylate and styrene.

A novel strategy for fabrication of fluorescent hydroxyapatite based polymer composites through the combination of surface ligand exchange and self-catalyzed ATRP

A novel and facile strategy that combination of surface ligand exchange and photo-initiated atom transfer radical polymerization (ATRP) has been developed for the preparation of fluorescent hydroxyapatite (HAp) based polymer composites, which were utilized for biological imaging applications. In particular, the photo-initiated ATRP not only inherited advantages of traditional ATRP but also overcome its deficiencies such as high energy consumption, transition metal contamination and long reaction time. In this method, a hydrophilic and biocompatible PEGMA was introduced to enhance the hydrophilic and biocompatibility of HAp nanocomposites. Simultaneously, the HAp-poly(PEGMA-co-AcFl) composites are endowed with bright green fluorescence by grafting with AcFl on the surface via copolymerization. The physicochemical properties of HAp-poly(PEGMA-co-AcFl) composites were characterized by a series of methods in detail. Results confirmed that HAp-poly(PEGMA-co-AcFl) composites possess controlled size and morphology, high water dispersibility and strong fluorescence. The cell viability and cell uptake behavior demonstrated that HAp-poly(PEGMA-co-AcFl) composites present low toxicity and can be potentially used for biological imaging. Taken together, we have developed a facile and efficient method for the fabrication of fluorescent HAp composites with desirable physicochemical and biological properties.

Visible‐Light‐Induced C−H Functionalization and C−C/C−X Bond‐Forming Oxidative Cross‐Coupling Reactions

AbstractTransition‐metal‐catalyzed C−H functionalization has been a hot topic in organic chemistry over the past decade. The convergence of photocatalysis and C−H functionalization is undoubtedly a promising strategy to solve the challenges in this area as photoinduced electron transfer represents another avenue for the activation of C−H bonds. In addition to the common merits of mild reaction conditions and good site selectivity, organic photoredox catalysts are superior to the transition metal photocatalysts (predominantly Ru‐ and Ir‐based polypyridyl complexes) in the following aspects: no potential transition metal contamination, low price, more candidates, and higher reactivity, and so forth. In this Focus Review, we concentrate on bond‐forming reactions by oxidative cross‐coupling using organic photoredox catalysts. Achievements on C−C and C−X (N, O, F, P, S, Cl, or Br) bond‐forming reactions made in recent years are summarized.

Ferromagnetism observed in silicon-carbide-derived carbon

Carbide-derived carbon (CDC) is prepared by etching high purity 4H-SiC single crystals in a mixed atmosphere of 5% ${\mathrm{Cl}}_{2}$ and 95% Ar for 120 min and 240 min. The secondary ion mass spectroscopy (SIMS) bulk analysis technique excludes the possibility of ferromagnetic transition metal (TM) contamination arising during the experimental process. The paramagnetic and ferromagnetic components are separated from the measured magnetization-magnetic field curves of the samples. Through the use of the Brillouin function, paramagnetic centers carrying a magnetic moment of $\ensuremath{\sim}1.3\phantom{\rule{0.28em}{0ex}}{\ensuremath{\mu}}_{B}$ are fitted. A resolvable hysteresis loop in the low magnetic field area is preserved at room temperature. The temperature dependence of the relative intensity of the Lorentzian-like electron spin resonance (ESR) line observed by electron spin spectroscopy reveals the existence of exchange interaction between the localized paramagnetic centers. First-principles calculations show the dominant configuration of defects in the graphitic CDC films. By calculating the energy difference between the antiferromagnetic and ferromagnetic phases, we deduce that the ferromagnetic coupling is sensitive to the concentration of defects.

Mechanisms induced by transition metal contaminants and their effect on the hydrothermal stability of zirconia-containing bioceramics: an XPS study.

Zirconia containing bioceramics suffer from low temperature degradation in biological and hydrothermal environments, and the presence of transition metal contamination has been shown to greatly affect the zirconia stability in different materials. In this paper, X-ray photoelectron spectroscopy was used to investigate the compositional and structural variations of different zirconia containing hip-joint bioceramics with and without transition metal stains in hydrothermal environments. Non-stained and stainless-steel-stained femoral head samples of 3 mol% Y2O3 doped tetragonal zirconia polycrystals (3Y-TZP) and zirconia-toughened alumina (ZTA) subjected to isothermal treatments in water vapor were investigated with quantifying their respective compositional XP lines. The outputs of these spectroscopic experiments revealed a significant difference in the off-stoichiometric reactions taking place at the surface of zirconia-containing ceramics in the presence and absence of transition metal contamination. The complex off-stoichiometric chemistry that occurred in the presence of metal contaminants could be interpreted in terms of defect-related chemical reactions among metal, water vapor, and oxide lattice, with a crucial contribution of the alumina phase in the transformation kinetics of ZTA.

Retention of contaminants Cd and Hg adsorbed and intercalated in aluminosilicate clays: A first principles study.

Layered clay materials have been used to incorporate transition metal (TM) contaminants. Based on first-principles calculations, we have examined the energetic stability and the electronic properties due to the incorporation of Cd and Hg in layered clay materials, kaolinite (KAO) and pyrophyllite (PYR). The TM can be (i) adsorbed on the clay surface as well as (ii) intercalated between the clay layers. For the intercalated case, the contaminant incorporation rate can be optimized by controlling the interlayer spacing of the clay, namely, pillared clays. Our total energy results reveal that the incorporation of the TMs can be maximized through a suitable tuning of vertical distance between the clay layers. Based on the calculated TM/clay binding energies and the Langmuir absorption model, we estimate the concentrations of the TMs. Further kinetic properties have been examined by calculating the activation energies, where we found energy barriers of ∼20 and ∼130 meV for adsorbed and intercalated cases, respectively. The adsorption and intercalation of ionized TM adatoms were also considered within the deprotonated KAO surface. This also leads to an optimal interlayer distance which maximizes the TM incorporation rate. By mapping the total charge transfers at the TM/clay interface, we identify a net electronic charge transfer from the TM adatoms to the topmost clay surface layer. The effect of such a charge transfer on the electronic structure of the clay (host) has been examined through a set of X-ray absorption near edge structure (XANES) simulations, characterizing the changes of the XANES spectra upon the presence of the contaminants. Finally, for the pillared clays, we quantify the Cd and Hg K-edge energy shifts of the TMs as a function of the interlayer distance between the clay layers and the Al K-edge spectra for the pristine and pillared clays.

Origin of orange color in nominally undoped HVPE GaN crystals

In this article we investigated unintentionally doped (UID) GaN grown by hydride vapor phase epitaxy (HVPE) with respect to point defects and impurity concentration. The samples were orange tinted to different extent. Optical analysis was performed by micro-photoluminescence and absorption spectroscopy. Absorption measurements revealed an absorption peak at 1.5 eV related to an internal transition in Mn3+ impurities and a second band with low energy onset at 1.9 eV, both increasing with the extent of orange color. Electron paramagnetic resonance investigations showed the presence of Mn2+ and Fe3+ in the colored crystals. The overall impurity concentration was verified by secondary ion mass spectrometry. Orange tint is associated with an increase of transition metal contamination, especially Mn. Based on these observations we suggest that the orange coloring in the investigated UID HVPE GaN samples is caused by the presence of Mn impurities.

Metal- and additive-free photoinduced borylation of haloarenes.

Boronic acids and esters have critical roles in the areas of synthetic organic chemistry, molecular sensors, materials science, drug discovery, and catalysis. Many of the current applications of boronic acids and esters require materials with very low levels of transition metal contamination. Most of the current methods for the synthesis of boronic acids, however, require transition metal catalysts and ligands that must be removed via additional purification procedures. This protocol describes a simple, metal- and additive-free method of conversion of haloarenes directly to boronic acids and esters. This photoinduced borylation protocol does not require expensive and toxic metal catalysts or ligands, and it produces innocuous and easy-to-remove by-products. Furthermore, the reaction can be carried out on multigram scales in common-grade solvents without the need for reaction mixtures to be deoxygenated. The setup and purification steps are typically accomplished within 1-3 h. The reactions can be run overnight, and the protocol can be completed within 13-16 h. Two representative procedures that are described in this protocol provide details for preparation of a boronic acid (3-cyanopheylboronic acid) and a boronic ester (1,4-benzenediboronic acid bis(pinacol)ester). We also discuss additional details of the method that will be helpful in the application of the protocol to other haloarene substrates.

Reconciling in vivo and in vitro kinetics of the polymorphic transformation in zirconia-toughened alumina for hip joints: II. Theory

In this paper, an updated analytical model for the kinetics of the tetragonal to monoclinic (t→m) polymorphic transformation in ZTA composites for hip joints is proposed and discussed. The model builds upon the so-called Mehl-Avrami-Johnson (MAJ) description of transformation kinetics, which combines two overlapping processes: nucleation of monoclinic sites, and their successive growth. Dependencies on two specific factors are introduced in the model, namely the initial fraction of monoclinic polymorph as received from the manufacturer, and the presence of different types of transition-metal stains (e.g., Ti, CoCr, and Fe) on the ZTA surface. These two factors were studied because clear indications of their potential roles on the environmental stability of implantable ZTA components were found in previous phenomenological analyses of retrievals. Nucleation and growth of monoclinic domains are two key processes whose interplay decides the actual kinetics of the overall transformation process according to two main parameters: an apparent activation energy value function of time and temperature, and a nuclei growth exponent. These parameters were clearly altered by the presence of transition metal contamination, whose effect was incorporated into the model to explain exacerbations of surface degradation. In accordance with a general analytical description of transformation kinetics for isothermal or isochronal evolutions in terms of time and temperature, the modified model of the MAJ description assesses the effect of the initial monoclinic fraction. The updated model has been validated using systematic in vitro experiments, and appears to partly reconcile in vitro and in vivo data of t→m transformation discrepancies in ZTA hip components.

Gram-Scale Synthesis of Nitrogen-Doped Carbon Foams As Template-Free, Metal-Free, Non-Precious Electrocatalysts for Oxygen Reduction and CO2 Conversion

Carbon foams are ideal materials for electrochemical applications due to their large surface area, high electrical conductivity, and stability over a wide electrochemical potential window. However, many of these materials are expensive; use complex multi-step synthesis protocols; and require the use of nanostructured template materials which must be removed with strong acid or alkaline. It is often difficult to control the porosity (and thereby optimize mass diffusion); and it is difficult to dope effectively with heteroatoms. We synthesize carbon foams at low cost and gram-scale, with large micron-scale pores, very thin walls, and very large surface area (e.g. 2500 m2/g), by thermal decomposition of sodium ethoxide.[1,2] Crucially, by synthesizing and subsequently decomposing nitrogen-containing metal alkoxides, nitrogen-doped carbon foams can be made.[3] The nitrogen content can be varied over a wide range (e.g. <0.5 to 15 at%) by simply changing e.g. the precursor ratios. In addition, the ratio of e.g. pyridinic to tertiary nitrogen bonding can be tailored by changing the pyrolysis temperature. These materials do not contain transition metal contamination (confirmed by ICP-AES), unlike carbon nanotubes or carbon black. Therefore they can be used to probe the fundamental oxygen reduction reaction (ORR) activity of nitrogen-doped carbon in acid – a relatively under-represented topic, plagued by contamination issues.[4,5] We observe surprisingly high mass activity and onset potential for the ORR, with high electron transfer number. This work shows that 4-electron ORR is possible even in the absence of transition metals, most likely associated with tertiary nitrogen sites.[6] In alkaline medium, these catalysts are comparable to Pt/C, and undergo negligible degradation even over 60,000 load potential cycles.[7] Finally, these materials are investigated for their electrochemical CO2 conversion activity to carbon monoxide, formic acid, methane, and ethane.

Doped and Decorated Graphene Foam Electrocatalysts

Graphene is an ideal material for electrochemical applications due to high electrical conductivity, large surface area, and stability over a wide electrochemical potential window. However graphene is expensive; it is difficult to control porosity (and thereby mass diffusion); and it is difficult to dope effectively. Simple carbon foams with large micron-scale pores, very thin walls, and very large surface area (e.g. 2500 m2/g) can be synthesized at low cost by thermal decomposition of sodium ethoxide.[1,2] Crucially, by decomposing nitrogen-containing alkoxides, nitrogen-doped graphene powders are made.[3] These do not contain transition metal contamination, as is the case with carbon nanotubes and carbon black. Therefore they can be used to probe the fundamental oxygen reduction reaction (ORR) activity of nitrogen-doped carbon in acid – a relatively under-represented research topic, plagued by contamination issues.[4,5] We record surprisingly high mass activity and onset potential for the ORR, with high electron transfer number (3.6). The negligible metal content was confirmed by ICP-AES. This work shows that 4-electron ORR is possible even in the absence of transition metals, most likely at (or adjacent to) tertiary nitrogen sites.[6] The activity in alkaline medium is also of interest, due to the development of new alkaline ion exchange membranes and the faster ORR kinetics. The nitrogen-doped graphene foams presented here display negligible degradation in cyclic voltammograms over 60,000 load potential cycles, demonstrating the applicability of such metal-free non-precious electrocatalysts in application that require long lifetimes.[7] [1] S. M. Lyth, H. Shao, J. Liu, K. Sasaki, Int. J. Hydrogen Energy, 2014, 39, 376[2] J. Liu, D. Takeshi, K. Sasaki, S. M. Lyth, J. Electrochem. Soc. 2014, 161, F838[3] S. M. Lyth, Y. Nabae, N. M. Islam, et al., eJournal of Surface Science and Technology, 2012, 10, 29-32.[4] S. M. Lyth, Y. Nabae, N. M. Islam, S. Kuroki, M. Kakimoto, S. Miyata, J. Nanosci. Nanotechnol. 2012, 12, 4887[5] S. M. Lyth, Y. Nabae, N. M. Islam, S. Kuroki, M. Kakimoto, S. Miyata, J. Electrochem. Soc. 2011, 158, B194[6] J. Liu, D. Takeshi, D. Orejon, K. Sasaki, S. M. Lyth, J. Electrochem. Soc. 2014, 161, F544[7] J. Liu, K. Sasaki, S. M. Lyth, ECS Trans. 2014, 64, 1161 Figure 1