TiO2 Nanostructures as Anode Materials for Li/Na-Ion Batteries.

Here we summarize some results on the use of TiO2 nanostructures as anode materials for more efficient Li-ion (LIBs) and Na-ion (NIBs) batteries. LIBs are the leader to power portable electronic devices, and represent in the short-term the most adequate technology to power electrical vehicles, while NIBs hold promise for large storage of energy generated from renewable sources. Specifically, TiO2 an abundant, low cost, chemically stable and environmentally safe oxide represents in LIBs an alternative to graphite for applications in which safety is mandatory. For NIBs, TiO2 anodes (or more precisely negative electrodes) work at low voltage, assuring acceptable energy density values. Finally, assembling different TiO2 polymorphs in the form of nanostructures decreases diffusion distances, increases the number of contacts and offering additional sites for Na+ storage, helping to improve power efficiency. More specifically, in this contribution we highlighted our work on TiO2 anatase mesocrystals of colloidal size. These sophisticate materials; showing excellent textural properties, have remarkable electrochemical performance as anodes for Li/Na-ion batteries, with conventional alkyl carbonates electrolytes and safe electrolytes based on ionic liquids.

Respiratory syncytial virus infection induces a subset of types I and III interferons in human dendritic cells.

Whether respiratory syncytial virus (RSV) induces severe infantile pulmonary disease may depend on viral strain and expression of types I and III interferons (IFNs). These IFNs impact disease severity by inducing expression of many anti-viral IFN-stimulated genes (ISGs). To investigate the impact of RSV strain on IFN and ISG expression, we stimulated human monocyte-derived DCs (MDDCs) with either RSV A2 or Line 19 and measured expression of types I and III IFNs and ISGs. At 24h, A2 elicited higher ISG expression than Line 19. Both strains induced MDDCs to express genes for IFN-ß, IFN-α1, IFN-α8, and IFN-λ1-3, but only A2 induced IFN-α2, -α14 and -α21. We then show that IFN-α8 and IFN-α14 most potently induced MDDCs and bronchial epithelial cells (BECs) to express ISGs. Our findings demonstrate that RSV strain may impact patterns of types I and III IFN expression and the magnitude of the ISG response by DCs and BECs.

Toward a Better Understanding and Optimization of the Electrochemical Activity of Na-Ion TiO2 Anatase Anodes Using Uniform Nanostructures and Ionic Liquid Electrolytes.

TiO2 anatase has emerged as a promising anode for Na-ion batteries (SIBs). However, widespread use of this anode is severely limited by a series of factors that need to be identified and understood to further improve their electrochemical response. Here, we have taken benefit from the versatility of a self-assembly seeding-assisted method to obtain a variety of uniform high-surface-area undoped TiO2 anatase nanostructures. Electrodes built from these uniform nanostructures in combination with a safe ionic liquid electrolyte have allowed a systematic study on some of the factors that determine the electrochemical activity of Na-ion anatase anodes. Interestingly, the inherent low penetrability of the ionic liquid electrolyte has resulted in an unexpected asset to clarify large differences in Na+ uptake by different nanostructures. Basically, solid electrolyte interface (SEI) effects were maximized and therefore clearly separated from electrochemical reactions strictly associated with the anatase anode. Thus, for electrodes built from nanostructures that preserved their initial conformation after cycling, the first discharge showed Na+ uptakes well-beyond those of the Ti4+/Ti3+ redox couple. This large uptake has been associated with an apparent reversible reaction that operates below ca. 0.5-0.7 V and an irreversible mechanism that operates at lower voltages (ca. 0.3 V). However, for electrodes built from nanostructures that favored SEI formation, the irreversible reaction associated with the plateau at ca. 0.3 V was not observed during the first discharge. In accordance, the total Na+ uptake did not reach values beyond those of the corresponding Ti4+/Ti3+ redox couple. Irreversibility, in this case, is associated with SEI formation. Our results also establish the strong effect that size at different scale levels has in the electrochemical response of anatase anodes for SIBs (changes from ca. 6 to 11 nm in crystal sizes and from 50 to 80 in nanostructure sizes led to pronounced differences). This result emphasizes that any conclusions on mechanistic studies other than size effects must be done under strict control on size at various scales (size as a strict control variable at crystal level and nanostructure or in more general terms aggregate scale levels). Finally, we have found that at 30 and 60 °C the performance of the best of the electrodes, with the low-flammable and low-volatile ionic liquid electrolyte, is comparable to that of similar nanostructures immersed in their Li-ion electrolyte counterparts. This result is promising, as in stationary applications where SIBs could replace Li-ion batteries, large accumulation of storage components imposes more strict safety criteria. Basically, power criteria can be relaxed in response to more strict safety criteria.

Dissimilar Crystal Dependence of Vanadium Oxide Cathodes in Organic Carbonate and Safe Ionic Liquid Electrolytes.

Advances in Li metal anode stabilization, solid-state electrolytes, and capabilities to insert a variety of active ions (Li(+), Na(+), Mg(2+), and Al(3+)) have renewed the interest in layered vanadium oxides. Here we show that crystal characteristics such as size and crystallinity are fundamental variables that control the dissimilar electrochemical capabilities of 1D vanadium oxides immersed in different electrolytes (organic carbonates and safe electrolytes containing 80% of ionic liquid). We show that this opposite behavior can be understood in terms of a subtle interplay between crystal characteristics (size and crystallinity), electrolyte degradability, and the ionic conductivity of the electrolyte. Thus, through this control we are able to obtain pure 1D vanadium oxides that show reversibility in carbonate electrolytes at a cutoff voltage of 1.5 V (voltage region where insertion of more than two lithium ions is possible). Furthermore, these materials are able to uptake ca. 1.0 mol of Li at a rate of 20C (1C = 295 mAh/g) and retain excellent capabilities (Coulombic efficiency of 98% after 200 cycles at a rate of 5C). Finally, what, to our knowledge, is really remarkable is that this optimization allows building vanadium oxide electrodes with an excellent electrochemical response in a safe electrolyte composition (80% of ionic liquid). Specifically, we reach uptakes also at a cutoff voltage of 1.5 V of ca. 1.0 mol of Li after 200 cycles at 5C (charge/discharge) with Coulombic efficiencies higher than 99.5%.

Surfactant-Free Vanadium Oxides from Reverse Micelles and Organic Oxidants: Solution Processable Nanoribbons with Potential Applicability as Battery Insertion Electrodes Assembled in Different Configurations.

Vanadium oxides similar to other metal transition oxides are prototypes of multifunctionality. Implementing new synthesis routes that lead to dry vanadium oxide nanomaterials with good functional and structural properties as well as good processing capabilities is thus of general interest. Here we report a facile method based on reverse micelles for the growth at room temperature and atmospheric pressure of surfactant-free vanadium oxide nanoribbons that retain after drying excellent solution-processable capabilities. Essential for the success of the method is the use of a soluble organic oxidant that acts as oxidant and cosurfactant during the synthesis, and facilitates surfactant removal with a simple washing protocol. Interestingly, this simple surfactant removal protocol could be of general applicability. As a proof-of-concept of the functional, structural, and processing capabilities of the dry vanadium oxide nanoribbons here prepared, we have checked their lithium insertion capabilities as battery cathodes built upon different configurations. Specifically, we show efficient insertion both in dry nanoribbons processed as films using doctor blade and organic solvents and in dry nanoribbons infiltrated in three-dimensional metal collectors from aqueous suspensions.

Efficient removal of mercury from aqueous solutions and industrial effluent.

The objective of this study was to examine the ability of a solid waste produced during beneficiation of ornamental rocks to remove mercury (Hg) from an industrial effluent and aqueous solutions under various conditions. Batch studies have been carried out by observing the effects of pH, concentration of the adsorbate, contact time, and so on. Various sorption isotherm models such as Langmuir, Freundlich, and Tóth have been applied for the adsorbent. Film and intraparticle diffusion were both found to be rate-limiting steps. Adsorption was properly described by the Freundlich model (capacity constant of 0.3090 (mg g(-1))(mg L(-1))(-1/n) and adsorption intensity indicator of 2.2939), which indicated a favorable sorption and encouraged subsequent studies for treatment of Hg-containing industrial effluent. Industrial effluent treatment efficiency reached Hg removals greater than 90% by using ornamental rock solid waste (ORSW). Besides, desorption studies indicated that the maximum recovery of mercury was 100 ± 2% for 1 mol L(-1) HNO3 and 74 ± 8% for 0.1 mol L(-1) HNO3. The ORSW could be reused thrice without significant difference on the Hg removal rate from industrial effluent. These findings place ORSW as a promising efficient and low-cost adsorbent for the removal of Hg from aqueous solutions and industrial effluent.

An assessment of contaminant concentrations in toothed whale species of the NW Iberian Peninsula: part II. Trace element concentrations.

Concentrations of Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn were investigated in the liver and kidney of the five most common toothed whales off the Northwest Iberian Peninsula (NWIP), specifically common dolphin, long-finned pilot whale, harbour porpoise, striped dolphin and bottlenose dolphin. Differences were observed in the bioaccumulation of the above elements between the five species. The differences are probably related to biological factors such as age and sex and/or to ecological factors specific to each species such as feeding habits or bioavailability of the various elements. However, no significant relationship was observed between element accumulation and sex. Pilot whale and striped dolphin showed the highest concentrations of renal Cd and the highest concentrations of hepatic Hg and Se, while bottlenose dolphin showed the highest concentrations of Hg in kidneys. An analysis of inter-elemental relationships showed strong positive correlations between Hg and Se in the five species, however most individuals have Hg:Se molar ratio less than 1:1 indicating an excess of Se compare to Hg. This result, probably reflect the high proportion of young animals in the sample available for this study and/or that these animals had a good health status. We also observed a positive correlation in striped dolphins between Cd and Cu and between Cd and Zn in kidneys. In addition, comparing with other studies world-wide, the element concentrations (Hg and Cd) found in Iberian toothed whales indicate that these populations are not specially threatened by Hg and Cd exposure in the area.

An assessment of contaminant concentrations in toothed whale species of the NW Iberian Peninsula: part I. Persistent organic pollutants.

Concentrations and patterns of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the blubber of the five most common toothed whales off the Northwest Iberian Peninsula (NWIP), specifically common dolphin, long-finned pilot whale, harbour porpoise, striped dolphin and bottlenose dolphin, were investigated. The study revealed that differences in PCB and PBDE concentrations among the species are highly dependent on age and sex but also on ecological factors such as trophic level, prey type and habitat. Of the five species studied, bottlenose dolphin and harbour porpoise showed the greatest concentrations of PCBs. Both species exceed the toxic threshold of 17µgg(-1) lipid weight (PCB Aroclor equivalent) for health effects on marine mammals, for 100% and 75% of the individuals tested, respectively. Overall, the PCB and PBDE levels observed in the NWIP toothed whales were of the same order of magnitude or lower than those reported by previous studies in areas of the NE Atlantic. However, they are often higher than those for toothed whales from the southern Atlantic and Pacific Ocean.