High-power nitrided TiO2 carbon felt as the negative electrode for all-vanadium redox flow batteries

This work describes the design of an electrode with enhanced performance applied to all-vanadium redox flow batteries (VRFBs). This new electrode consists of a structural porous carbon felt decorated with TiO2 rutile nanoparticles, which has been nitrided using ammonolysis at 900 °C. An outstanding charge and mass transfer over the electrode-electrolyte interface was observed as a consequence of the synergetic effect of N- and O-functionalization over carbon felt (CF) and the partial formation of TiN (metallic conductor) phase. Moreover, this material has not only improved in terms of catalysis towards the V3+/V2+ redox reaction (k0 = 1.6 × 10−3 cm s−1), but also inhibited the hydrogen evolution reaction (HER), which is one of the main causes of imbalances that lead to battery failure. This led to an impressive high-power peak output value up to 700 mW cm−2, as well as work at high current density in galvanostatic conditions (i.e. 150 mA cm−2), exhibiting low ohmic losses (overpotential) and great redox single cell reversibility, with a superior energy efficiency of 71%. An inexpensive, earth abundant and scalable synthesis method to boost VRFBs technology based on nitrided CF@TiO2 is presented, being able to overcome certain constrains, and therefore to achieve high energy and power densities

The Use of Graphitic Carbon Nitride Based Composite Anodes for Lithium-Ion Battery Applications

Graphitic carbon nitride (gCN) is shown to undergo lithium insertion reactions applicable with lithium-ion battery anodes. Lithium capacity was found to be substantially lower than theoretically expected, so the properties of gCN composited with conducting graphite (CG), which was added to improve the performance, were investigated. The electrodes exhibited a systematic increase in lithium uptake with CG content, but the capacity never exceeded that of graphite. It is shown that electron transport via conducting pathways was limiting. Li+ uptake for 10 % gCN was similar to a graphite electrode, indicating that gCN does play a role in determining the storage capacity

Restrictive ID policies: implications for health equity

We wish to thank Synod Community Services for their critical work to develop, support, and implement a local government-issued ID in Washtenaw County, MI. We also thank Yousef Rabhi of the Michigan House of Representatives and Janelle Fa'aola of the Washtenaw ID Task Force, Lawrence Kestenbaum of the Washtenaw County Clerk's Office, Sherriff Jerry Clayton of the Washtenaw County Sherriff's Office, and the Washtenaw ID Task Force for their tireless commitment to developing and supporting the successful implementation of the Washtenaw ID. Additionally, we thank Vicenta Vargas and Skye Hillier for their contributions to the Washtenaw ID evaluation. We thank the Curtis Center for Research and Evaluation at the University of Michigan School of Social Work, the National Center for Institutional Diversity at the University of Michigan, and the University of California-Irvine Department of Chicano/Latino Studies and Program in Public Health for their support of the Washtenaw ID community-academic research partnership. Finally, we thank the reviewers for their helpful comments on earlier drafts of this manuscript. (Curtis Center for Research and Evaluation at the University of Michigan School of Social Work; National Center for Institutional Diversity at the University of Michigan; University of California-Irvine Department of Chicano/Latino Studies; Program in Public Health)https://link.springer.com/content/pdf/10.1007/s10903-017-0579-3.pdfPublished versio

Effect of zirconia in the density and ionic conductivity properties of Bi4V1.8Cu0.1Zn0.1O10.7 compound

Ceramics based bismuth vanadate are conductors of oxygen ions and they are used as solid electrolytes in pressure sensors and fuel cells. These materials operate at temperatures above 700 °C. At high temperatures, the bismuth-vanadium oxide (Bi4V2O11) has a g-phase with a large number of oxygen vacancies that favors the ionic conductivity. The g-phase of the Bi4V2O11 was stabilized at room temperature by partial substitution of vanadium (V5+) ions by cuprum (Cu2+) and zinc (Zn2+) ions to provide high ionic conductivity values between 100 and 400oC. Thus, polycrystalline samples of Bi4V1.8Cu0.1Zn0.1O10.7 were obtained after 4h sintering at 800 °C. Investigations were made about densification process and ionic conductivity related to the effect of addition of the yttria-stabilized zirconia (Zr0.88Y0.12O1.94)

Synthesis of a Graphene-Encapsulated Fe 3 C/Fe Catalyst Supported on Sporopollenin Exine Capsules and Its Use for the Reverse Water–Gas Shift Reaction

Bioderived materials have emerged as sustainable catalyst supports for several heterogeneous reactions owing to their naturally occurring hierarchal pore size distribution, high surface area, and thermal and chemical stability. We utilize sporopollenin exine capsules (SpECs), a carbon-rich byproduct of pollen grains, composed primarily of polymerized and cross-linked lipids, to synthesize carbon-encapsulated iron nanoparticles via evaporative precipitation and pyrolytic treatments. The composition and morphology of the macroparticles were influenced by the precursor iron acetate concentration. Most significantly, the formation of crystalline phases (Fe3C, α-Fe, and graphite) detected via X-ray diffraction spectroscopy showed a critical dependence on iron loading. Significantly, the characteristic morphology and structure of the SpECs were largely preserved after high-temperature pyrolysis. Analysis of Brunauer–Emmett–Teller surface area, the D and G bands from Raman spectroscopy, and the relative ratio of the C═C to C–C bonding from high-resolution X-ray photoelectron spectroscopy suggests that porosity, surface area, and degree of graphitization were easily tuned by varying the Fe loading. A mechanism for the formation of crystalline phases and meso-porosity during the pyrolysis process is also proposed. SpEC-Fe10% proved to be highly active and selective for the reverse water–gas shift reaction at high temperatures (>600 °C)

Fe-N-Doped Carbon Capsules with Outstanding Electrochemical Performance and Stability for the Oxygen Reduction Reaction in Both Acid and Alkaline Conditions

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsnano.6b01247. Tables of reported ORR performance; Figures S1−S9 showing additional data as discussed in the text (PDF)This research work was supported by the Spanish Ministerio de Economıa y Competitividad, MINECO (MAT2012-31651), ́ Fondo Europeo de Desarrollo Regional (FEDER), and FICYT Regional Project (GRUPIN14-102). G.A.F. thanks the MINECO for his predoctoral contract, and M.S. thanks the Spanish Ministerio de Ciencia e Innovacion for her Ramo ́ n y ́ Cajal contract

the Portuguese case

BACKGROUND: Portugal has one of the most severe HIV-1 epidemics in Western Europe. Two subtypes circulate in parallel since the beginning of the epidemic. Comparing their transmission patterns and its association with transmitted drug resistance (TDR) is important to pinpoint transmission hotspots and to develop evidence-based treatment guidelines. METHODS: Demographic, clinical and genomic data were collected from 3599 HIV-1 naive patients between 2001 and 2014. Sequences obtained from drug resistance testing were used for subtyping, TDR determination and transmission clusters (TC) analyses. RESULTS: In Portugal, transmission of subtype B was significantly associated with young males, while transmission of subtype G was associated with older heterosexuals. In Portuguese originated people, there was a decreasing trend both for prevalence of subtype G and for number of TCs in this subtype. The active TCs that were identified (i.e. clusters originated after 2008) were associated with subtype B-infected males residing in Lisbon. TDR was significantly different when comparing subtypes B (10.8% [9.5-12.2]) and G (7.6% [6.4-9.0]) (p = 0.001). DISCUSSION: TC analyses shows that, in Portugal, the subtype B epidemic is active and fueled by young male patients residing in Lisbon, while transmission of subtype G is decreasing. Despite similar treatment rates for both subtypes in Portugal, TDR is significantly different between subtypes.publishersversionpublishe