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Electrochemical recovery of the cobalt in deep eutectic solvent shows its promise in recycling and recovery of valuable elements from the spent lithium-ion battery due to its high selectivity and minimal environmental impacts. This work unveiled the roles of the substrates, applied potentials and operating temperatures on the performance of cobalt electrochemical recovery in a deep eutectic choline chloride + urea solvent. The solvent contains cobalt and lithium ions extracted from lithium cobalt oxides - an essential lithium-ion battery cathode material. Our results highlight that the substrate predetermines the cobalt recovery modes via substrate-cobalt interactions, which could be predicted by the cobalt surface segregation energies and crystallographic misfits. We also show that a moderate cathode potential under -1.0 V vs. silver quasi-reference electrode at 94 °C - 104 °C is essential to ensure a selective cobalt recovery at an optimal rate. We also found that the stainless-steel mesh as an optimal substrate for cobalt recovery due to its relatively high selectivity, fast recovery rate, and easy cobalt collection and substrate regeneration. Our work provides new insights on metal recovery in deep eutectic solvents and offers a new avenue to control the metal electrodeposition modes via modulation of substrate compositions and crystal structures.

Interactions of electrolyte ions at electrocatalyst surfaces influence the selectivity of electrochemical CO2 reduction (CO2R) to chemical feedstocks like CO. We investigated the effects of anion type in aqueous choline halide solutions (ChCl, ChBr, and ChI) on the selectivity of CO2R to CO over an Ag foil cathode. Using an H-type cell, we observed that halide-specific adsorption at the Ag surface limits CO faradaic efficiency (FECO) at potentials more positive than −1.0 V vs. reversible hydrogen electrode (RHE). At these conditions, FECO increased from I−−−, that is, in the opposite order to the strength of specific adsorption of the halide ions (Cl−−−). At potentials of −1.0 to −1.3 V vs. RHE, restructuring of the Ag surface in ChI and ChCl via dissolution and re-electrodeposition led to more CO-selective Ag facets ([220], [311], and [222]) than in ChBr. This mechanism allowed very high faradaic efficiencies for CO of 97±2 % in ChI and 94±2 % in ChCl to be achieved simultaneously with high current densities at −1.3 V vs. RHE. We also demonstrate that high selectivity to CO (FECO>90 %) in ChCl (at −0.75±0.06 Vvs. RHE) and ChI (at −0.78±0.17 V vs. RHE) could be achieved at a current density of 150 mA cm−2 in a continuous flow-cell electrolyser with Ag nanoparticles on a commercial gas diffusion electrode. This study provides new insights to understand the interactions of anions with catalysts and offers a new method to modify electrocatalyst surfaces.

Synthesizing mesoporous alloys composed of metals with divergent reactivities and standard redox potentials (E0) is challenging because the kinetics of metal deposition is totally different. Herein, we report the first method to generate mesoporous RhNi alloy films via electrochemical co-deposition using self-assembled micelle templates. The concentration of Rh precursor (Rh3+) is crucial to control reaction kinetics and morphology because Rh deposition is the trigger of Ni co-deposition. The ratio of Rh3+ : Ni2+ (in the precursor) can be altered to generate different alloy compositions, and the impact of pH and deposition potentials is also investigated. We examine the mesoporous RhNi films as electrocatalytic electrodes for the hydrogen evolution reaction (HER). Ni-doping serves to enhance the HER performance of the mesoporous films, and the 1 : 1 alloy (mesoporous Rh49Ni51 film) shows the best performance with the overpotential of 59 mV @ 10 mA cm−2 and Tafel slope of 67 mV dec−1. The insight gained here will enable researchers to experiment with different noble-transition metal alloys to generate better porous electrodes for electrocatalysis.

Pursuing high catalytic selectivity is challenging but paramount for an efficient and low-cost CO2 electrochemical reduction (CO2R). In this work, we demonstrate a significant correlation between the selectivity of CO2R to formate and the duration of tin (Sn) electrodeposition over a cuprous oxide (Cu2O)-derived substrate. A Sn electrodeposition time of 120 s led to a cathode with a formate Faradaic efficiency of around 81% at -1.1 V vs reversible hydrogen electrode (RHE), which was more than 37% higher than those of the Sn foil and the sample treated for 684 s. This result highlights the significant role of the interface between deposited Sn and the cuprous-derived substrate in determining the selectivity of CO2R. High-resolution X-ray photoelectron spectra revealed that the residual cuprous species at the Cu/Sn interfaces could stabilize Sn species in oxidation states of 2+ and 4+, a mixture of which is essential for a selective formate conversion. Such modulation effects likely arise from the moderate electronegativity of the cuprous species that is lower than that of Sn2+ but higher than that of Sn4+. Our work highlights the significant role of the substrate in the selectivity of the deposited catalyst and provides a new avenue to advance selective electrodes for CO2 electrochemical reduction.

Modification of conventional photoanode with oxide nanoparticles is a practical tactic to improve the performance of electrochemical devices. In this study, erbium oxide (Er2O3) nanoparticles were mixed with the TiO2 paste and photovoltaic performance of the dye-sensitized solar cell (DSSC) was investigated. The highest power conversion efficiency of 6.39% was reached with the 1 wt.% of Er2O3 in photoanode, while in the similar condition the device with the pure TiO2 photoanode achieved the power conversion efficiency of 3.54%. This improvement in the power conversion efficiency was attributed to declining in charge recombination, improved open-circuit voltage and short-circuit current due to the presence of the critical amount of Er2O3. XPS analysis confirms the structural coherence between the Er2O3 and TiO2, which enhanced the optical performance of the composite photoanode. Composite photoanodes were further characterized by FESEM-EDX, XRD, and AFM for structural and morphological studies.

Changes in physiochemical properties of spray-dried camel milk powders during storage at 11–32% RH and 37 °C over 18 weeks were investigated. The results showed that fresh camel milk powders had amorphous structure, clumsy spherical shape particles and almost 100% solubility in water. During storage at controlled low RH levels (

Water-induced crystallisation of amorphous core-cyclodextrin (CD) complex is an essential step in a solid encapsulation process and removal of added water is a challenging. Ethanol addition is expected to shorten the complex dehydration time. This study investigated crystallisation of amorphous spray-dried α-, β- and γ-CD powders by direct mixing 15% (w/w) of ethanol:water mixture (0:100, 20:80, 40:60, 60:40, 80:20 and 100:0) over 72 h period. The results showed α- and β-CD powders crystallised at all concentrations of ethanol solutions. Especially mixed with 0:100 and 20:80 ethanol:water solutions, the crystallisation behaviour of α- and β-CD powders was similar to that of commercial crystalline counterparts. γ-CD powders exhibited a crystallisation sign as mixed with 0:100 and 20:80 ethanol:water solutions only. In the study of fish oil encapsulation using the mixture of water and ethanol to induce the complex crystallisation, only γ-CD powder was able to form complex with fish oil.

Strontium cobalt-based perovskites display high electrochemical activity but poor stability for solid oxide electrolysis cells (SOECs). Here, we evaluate the stability of three strontium cobalt-based materials, i.e. SrCo0.8Nb0.2O3-δ (SCN), SrCo0.8Ta0.2O3-δ (SCT) and SrCo0.8Nb0.1Ta0.1O3-δ (SCNT) as air electrodes for SOECs. The electrochemical results show that the area-specific resistance (ASR) for SCN and SCNT cells decreases and then becomes almost constant whereas the ASR of the SCT cell continuously increases, during the 240 h SOEC test. The improved performance of SCN and SCNT cells is ascribed to the lower energy barrier required for the oxide ion movement in the presence of niobium and the less concentration of undesired phases formed during SOEC operation. SCN is further tested under reversible solid oxide cell (RSOC) conditions with 16 h solid oxide fuel cell (SOFC) and 7 h SOEC cycles. The cell presents excellent stability as its impedance increases only slightly from 0.188 to 0.193 Ω cm2 after 114 h RSOC test. A single cell with NiO-SSZ/SSZ/SDC/SCN configuration shows high electrolysis current densities of 0.51, 0.42 and 0.34 A cm−2 at 800, 750 and 700 °C, respectively, in 10% H2O/90% H2 and 0.79 A cm−2 at 800 °C in 50% H2O/50% H2 at 1.3 V.

Southwest Turkey is seismically active as a result of the Hellenic subduction process in the Eastern Mediterranean. We conducted high-resolution micro-sampling, high-precision U-series dating and microchemical analysis on an extensional vein system in a tectonically active but non-hydrothermal area. U/Th age data and microscopic observations provide evidence of repeated fracturing of a previously sealed crack system followed by a new increment of veining. Repeated injection of veinlets suggests that the vein system was formed by the crack-seal mechanism. Four major U/Th age groups for the emplacement of the vein system fall between 23.9 +/- 0.2 ka and 23.2 +/- 0.4 ka, 21.7 +/- 0.4 ka and 19.2 +/- 0.2 ka, 17.3 +/- 0.1 ka and 16.2 +/- 0.3 ka, and at 11.8 +/- 0.2 ka. Stable and Sr isotope geochemistry of the calcite vein samples indicates that surface water interacting with the soil cover was the major component of the groundwater system from which the extensional veins precipitated. Trace element and 0 isotope data of the vein system are interpreted to reflect carbonate precipitation associated with seismic cycles involving fluids with different trace element compositions and CO2 contents. Initial carbonate precipitation during a single seismic cycle occurred from CO2-dominated fluids that were degassed from the original CO2 water mixture. This was followed consecutively by carbonate precipitation from the remaining water, which was relatively impure with higher trace element contents. Millimetre to submillimetre-scale U-series dating in conjunction with geochemistry of carbonate veins related to active tectonism offers an innovative means of constraining the absolute timing of late Quaternary seismic and inter-seismic events. (C) 2010 Elsevier B.V. All rights reserved.

Cultures of Trichodesmium from the Northern and Southern Great Barrier Reef Lagoon (GBRL) have been established in enriched seawater and artificial seawater media. Some cultures have been maintained with active growth for over 6 years. Actively growing cultures in an artificial seawater medium containing organic phosphorus (glycerophosphate) as the principal source of phosphorus have also been established. Key factors that contributed to the successful establishment of cultures were firstly, the seed samples were collected from depth, secondly, samples were thoroughly washed and thirdly, incubations were conducted under relatively low light intensities (PAR similar to 40-50 mumol quanta m(-2) s(-1)). N-2 fixation rates of the cultured Trichodesmium were found to be similar to those measured in the GBRL. Specific growth rates of the cultures during the exponential growth phase in all enriched media were in the range 0.2-0.3 day(-1) and growth during this phase was characterised by individual trichomes (filaments) or small aggregations of two to three trichomes. Characteristic bundle formation tended to occur following the exponential growth phase, which suggests that the bundle formation was induced by a lack of a necessary nutrient e.g. Fe. Results from some exploratory studies showed that filament-dominated cultures of Trichodesmium grew over a range of relatively low irradiances (PAR similar to 5-120 mumol quanta m(-2) s(-1)) with the maximum growth occurring at - 40-50 mumol quanta m(-2) s(-1). These results suggest that filaments of the tested strain are well adapted for growth at depth in marine waters. Other studies showed that growth yields were dependent on salinity, with maximum growth occurring between 30 and 37 psu. Also the cell yields decreased by an order of magnitude with the reduction of Fe additions from 450 to 45 nM. No active growth was observed with the 4.5 nM Fe addition.

Doped ceria (CeO2) compounds are fluorite type oxides which show oxide ionic conductivity higher than yttria stabilized zirconia, in oxidizing atmosphere. As a consequence of this, considerable interest has been shown in application of these materials for ‘low temperature operation (500–650 °C)’ of solid oxide fuel cells (SOFCs). In this study, YxCe1−xO2−δ ( x=0.05, 0.1, 0.15, 0.2 and 0.25) fine powders were prepared using a carbonate co-precipitation method. The relationship between electrolytic properties and nano-structural features in the sintered bodies was examined. The micro-structures of Y0.05Ce0.95O1.975, Y0.15Ce0.85O1.925 and Y0.25Ce0.75O1.875 as representative three specimens have been investigated in more detail with transmission electron microscopy (TEM). The big diffuse scattering was observed in the background of electron diffraction pattern recorded from Y0.15Ce0.85O1.925 and Y0.25Ce0.75O1.875 sintered bodies. This means that the coherent micro-domain with ordered structure is in the micro-structure. While Y0.25Ce0.75O1.875 sintered body with low conductivity and high activation energy has big micro-domains, the micro-domain size in Y0.15Ce0.85O1.925 with high conductivity and low activation energy was much smaller than that of Y0.25Ce0.75O1.875. TEM observation gives us message that the size of coherent micro-domain with ordered structure would closely relate to the electrolytic properties such as conductivity and activation energy in the specimens. It was concluded that a control of micro-domain size in nano-scale in Y2O3 doped CeO2 system was a key for development of high quality solid electrolyte in fuel cell application.

This study aims to compare the relaxivities of ultra-small dual positive and negative contrast iron oxide nanoparticles (DCION) at different magnetic field strengths ranging from 4.7 to 16.4 T at physiological temperatures; and to investigate the effect of particle aggregation on relaxivities. Relaxivities of DCIONs were determined by magnetic resonance imaging scanners at 4.7, 7, 9.4, and 16.4 T. Both longitudinal (T 1) and transverse relaxation times (T 2) were measured by appropriate spin-echo sequences. It has been found that both longitudinal and transverse relaxivities are significantly dependent on the magnetic field strength. Particle aggregation also strongly affects the relaxivities. Awareness of the field strength and particle colloid stability is crucial for the comparison and evaluation of relaxivity values of these ultra-small iron oxide nanoparticles, and also for their medical applications as contrast agents.

Weather damage by rainfall is a major constraint to production of high quality mungbean seed. Breeding mungbeans for weathering resistance is assisted by an understanding of the pod wall structure and how this structure can affect water absorption. This paper describes a simple microscopic technique for determining the transport route of salt solutions from the external pod surface through the pod wall tissues and into the pod lumen. Different mungbean cultivars were selected based on differences in field performance. Mungbean pods were immersed in concentrated salt solutions (lanthanum nitrate, caesium chloride and sodium chloride) for different time periods, embedded in resin blocks and polished prior to backscatter imaging in a field emission scanning electron microscope. The salts precipitated between the pod wall tissues and through timed experiments clearly demonstrated the passage of salt solution through the pod wall tissues and into the pod lumen. The salt molecules penetrated the outer epidermis and parenchyma but were unable to penetrate the dense sclerenchymatous layer beneath. The salt solution entered the lumen of the pod via the small gap between the suture cap and the dense tissue sheath. Although this technique may not provide a true determination of fresh water absorption through mungbean pods it does demonstrate a simple means of identifying more resistant pod structures suitable for use in achieving genetic improvement.

The study identifies the various components contributing to atmospheric particulate matter in Brisbane, Queensland, Australia, during the period from the end of April and the months of July–August in 1992, covering the autumn period which is typically the period of high asthma incidence in Brisbane. Most particulate matter is < 2 μm and submicronic. Electron microscopy revealed that the submicron material is composed mainly of combusted (“soot”) and incompletely burned hydrocarbons arising from motor vehicle exhaust emissions, crustal matter in the form of quartz microconcretions and other silicates, quiescent spores of Mucorales, and soil bacteria. The contribution from pollen and fungal spores has been evaluated and quantified. Fungal spores counts dominate the bioaerosol counts in the 2–10 μm range and are very high in Brisbane from the end of April through May to mid-June. However even at peak periods the total bioaerosol count only contributes of the order of 5–10% of the total particulate mass. The results show that Pm10 (particulate matter less than 10 μm in diameter) and nephelometer readings do not indicate peak periods of allergenic bioaerosol readings (in fact there is a negative correlation) due to the low contribution of the bioaerosol count to the total and the different influences of wind speed. However the electron microscopy results show that this does not mean there are no synergies between aerosols from anthropogenic sources and bioaerosols. The cytoplasmic content of spores and pollen was often found to be adhered to motor vehicle emission material and crustal matter. The latter may therefore act as carriers for dispersed cytoplasmic allergenic material released from pollen and fungal spores.

Bulk and size-fractionated kaolinites from seven localities in Australia as well as the Clay Minerals Society Source Clays Georgia KGa-1 and KGa-2 have been studied by X-ray diffraction (XRD), laser scattering, and electron microscopy in order to understand the variation of particle characteristics across a range of environments and to correlate specific particle characteristics with intercalation behavior. All kaolinites have been intercalated with N-methyl formamide (NMF) after pretreatment with hydrazine hydrate, and the relative efficiency of intercalation has been determined using XRD. Intercalate yields of kaolinite: NMF are consistently low for bulk samples that have a high proportion of small-sized particles (i.e., 60%) of low-defect phase. In general, particle size appears to be a more significant controlling factor than defect distribution in determining the relative yield of kaolinite: NMF intercalate.

The Clay Minerals Society Source Clay kaolinites, Georgia KGa-1 and KGa-2, have been subjected to particle size determinations by 1) conventional sedimentation methods, 2) electron microscopy and image analysis, and 3) laser scattering using improved algorithms for the interaction of light with small particles. Particle shape, size distribution, and crystallinity vary considerably for each kaolinite. Replicate analyses of separated size fractions showed that in the