Enabling the use of seawater for hydrogen gas production in water electrolyzers

PLoS Biology has published a research article that investigates a bibliometric rather than a biological question: do open-access articles have a citation advantage?

The Proceedings of the National Academy of Sciences (PNAS) has introduced an OA option for authors. Quoting today's press release: "PNAS authors may opt to pay a $1000 surcharge to make their articles available for free via PNAS Online and PubMed Central immediately upon publication. PNAS will offer this open access option as an experiment until December 31, 2005.

Hydrogen production by alkaline water electrolysis using hydroxide anion exchange membranes has seen a renewed interest as an alternative to traditional liquid alkaline water electrolyzers, proton exchange membrane (PEM) electrolyzers, and solid oxide water electrolyzers (1). Anion exchange membrane electrolyzers provide an efficient, modular, and reliable method to produce hydrogen from water and renewable electricity sources. One of the main benefits of anion exchange membrane electrolyzers arises from better oxygen evolution reaction (OER) kinetics in alkaline environments and the possibility of employing non-platinum group catalysts (non-PGM) and PGMs modified with transition metals for enhanced activity without suffering the stability problems common in acid media. However, one challenge is the sluggish kinetics for the HER in alkaline media. During our comprehensive research into active and stable OER catalysts for alkaline operation, pyrochlores emerged as among the most active and stable OER catalysts reported in the literature. Electrically conducting metal oxides (eliminating the need of a conducting support for the catalyst) with the pyrochlore structure (A2B2O7-y, with A=Pb or Bi and B= Ru, Ir or Os) were synthesized via precipitation/crystallization in alkaline medium and/or via solid-state reaction. The electrocatalytic activity for the oxygen evolution reaction (OER) in 0.1M KOH showed that lead and bismuth ruthenate pyrochlores had significantly lower overpotentials for the OER than the state-of-the-art IrO2 catalyst. Specific activities (at 1.5 V vs. RHE) of 3.0±0.2 Am-2, 1.3±0.2 Am-2 and 0.06±0.01 Am-2 were obtained for Pb2Ru2O6.5, Bi2.4Ru1.6O7, and IrO2 respectively. Specific activities for iridate-based pyrochlores (0.3-0.5 Am-2) were 5-10 times lower than those for ruthenate-based pyrochlores. Lead osmate pyrochlore showed the lowest OER activity among all the pyrochlores evaluated, with a specific activity of 0.10±0.07 Am-2. The exceptional OER activity and stability of lead ruthenate pyrochlore catalysts were evaluated in an anion exchange membrane water electrolyzer. The overpotentials obtained were 0.1-0.2 V lower than for IrO2 across the entire current density range and the performance was stable for at least 200 h. Since operation in alkaline media leads to more sluggish HER kinetics, we have evaluated ways to improve the HER catalytic kinetics of Pt electrocatalysts. Bifunctional electrocatalysts containing Pt clusters to combine the protons to form hydrogen gas, and hydrophilic domains able to help in water dissociation are promising candidates to substantially improve HER kinetics under alkaline conditions and to facilitate the introduction of commercial alkaline membrane water electrolyzers. The hydrophilic moieties that help the water splitting are varied. We have investigated nickel hydroxide and ruthenium oxide as co-catalysts together with Pt. Rotating disk electrode (RDE) measurements were performed in 0.1M KOH at temperatures ranging from 273.15 K to 303.15 K, and the HOR/HER kinetic currents, obtained after IR and mass transport corrections, were fitted using the Butler-Volmer equation to estimate the exchange current densities at each temperature. Arrhenius plots showed very similar activation energies for Pt/C (35±6 kJ/mol) and the bi-functional catalysts (38±6 kJ/mol) –Pt/C/X%Ni(OH)2. The maximum exchange current density (2.44±0.07 mA cm-2 Pt at 303.15 K) was obtained with the catalyst containing 10wt% Ni(OH)2, and was 2.4 times higher than for Pt/C (1.03±0.07 mA cm-2 Pt at 303.15 K). The bi-functional catalysts were evaluated in an anion-exchange membrane water electrolyzer operated with ultrapure water, and outperformed Pt/C by about 0.15 V across the entire current density range. Similarly, electrolyzer experiments showed that Pt/C/10%Ni(OH)2 performs as well as Pt/C with only half the Pt loading. Long-term stability experiments in the electrolyzer are ongoing. We have also found enhanced HER activity in a Pt electrocatalyst deposited onto a mixed-metal-oxide support composed of titanium dioxide (TiO2) and ruthenium dioxide (RuO2). The Pt/RuO2-TiO2 (Pt/RTO) electrocatalyst outperformed the benchmark Pt/C over the entire range of temperatures evaluated (275-313K). The exchange current density for Pt/RTO was 2.31±0.06mAcm-2 Pt (at 295 K), which was more than five times the value for Pt/C. In a solid-state alkaline water electrolyzer, MEAs fabricated with Pt/RTO in the cathode and IrO2 as anode catalyst exhibited a 100-200mV reduction in the cell voltage, when compared to MEAs fabricated with Pt/C in the cathode. References A. Brisse, J. Schefold and M. Zahid, Int. J. Hydrogen Energy, 33, 5375 (2008).

Boosting electrocatalytic water splitting by magnetic fields

At the dawn of the 21st century, mankind is facing an important energy challenge. Future energy demand can only be met by large scale exploitation of renewable energy resources. Solar energy is abundant, with a sufficient capacity for the growing energy demand. However, it is necessary to implement renewable energy storage means. Hydrogen is considered as the energy carrier of the future. An energy economy based on hydrogen is viable only if hydrogen is produced from sustainable means. Water electrolysis is the most promising technique to produce hydrogen directly from water. Yet, the efficiency is limited and electrocatalysts are required to drive both the hydrogen evolution reaction and oxygen evolution reaction. Scarce and expensive materials are currently used to drive these reactions. It is, thus, imperative that efficient Earth-abundant catalysts are developed. Nanostructuring enhances the performance of inexpensive materials for water splitting and several catalysts were studied for this goal. Chapter 2 describes the application of nanostructuring technique to the archetypical catalysts that are nickel oxides for oxygen evolution. The prepared nanoparticles show superior activity towards oxygen evolution than that of their bulk counterpart. The ultrafine size of nanoparticles synthesized allowed the exposure of a higher number of active sites. The activity for oxygen evolution was, thus, significantly enhanced. We also detailed that short conditioning of the electrode improved the performance of the evaluated materials. In chapter 3 we carefully studied nanoparticles and nanowires of nickel phosphide. The catalysts is known to be really active for hydrogen evolution. Our group suspected that this material was, also, a potential oxygen evolution catalyst. We proved, for the first time, that nickel phosphide is a remarkable oxygen evolution catalyst. Under alkaline conditions, used for oxygen evolution, we observed an in-situ formation of a core-shell heterostructure, a typical nanostructure architecture. The surface oxidation of this material allowed high oxygen evolution capabilities. We concluded that careful oxidation of nanostructured materials, as observed for nickel phosphide, is essential for the preparation of future outstanding oxygen evolution catalysts. Chapter 4 details the fabrication of direct solar-to-fuel electrode using cobalt phosphide as hydrogen evolving catalyst. Instead of using the electrical energy provided by solar energy, solar irradiation on the developed assembly allows direct hydrogen production. The careful design of the light-sensitive electrode (photocathode) is detailed. Simple incorporation of cobalt phosphide by means of photodeposition alleviates the cost of the electrode fabrication. The assembled electrode is active for hydrogen evolution under visible light irradiation. In the chapter 5 we sought to fabricate a 3-dimensional hydrogen evolving catalyst. This nanostructure is based on polymer brushes on a flat conducting substrate. Once the brushes are grown on the substrate, a molybdenum sulfide catalyst is then incorporated by simple soaking technique. We were able to tune the loading of the catalyst and the corresponding activity by changing the polymer properties. The height of the polymer was modified as well as its packing density. The resulting activity proved superior to similar approaches and to previous reports on carefully engineered molybdenum sulfide catalysts.

Modern trends in the development of electric distribution networks for agro-industrial facilities related to the introduction of more complex production technologies, increased consumer loads and stricter requirements for reliability and energy efficiency of networks are considered. In the conditions of sectoral supply restrictions and the need to replace imported components, the possibilities of implementing the advantages of distributed electric power in flexible energy supply of agro-industrial and social facilities on the basis of domestic technology and innovative methods are presented. (Research purpose) The research purpose is considering the technical support of distributed generation systems and analyzing possible problems that may arise during the integration of distributed generation sources into the electrical system of the agro-industrial complex. (Materials and methods) Used statistical data to analyze the availability of agro-industrial facilities with distributed electric power. (Results and discussion) It has been shown that the agro-industrial complex is dominated by objects that are far removed from the center of the energy system, with electrical equipment that is morally and technically outdated, which affects the reliability of power supply and the quality of electricity. It was determined that the introduction of distributed generation sources requires modernization or updating of the main electrical equipment of distribution points or substations. Alternative technical solutions have been proposed to improve the quality of electricity supplied to consumers and the reliability of power supply systems, focused on the maximum approximation of the power source to the consumer by placing distributed generation sources near the objects of the agro-industrial complex. They gave specific schemes of power supply systems, the results of technical and economic analysis and options for using traditional and renewable sources of electricity. (Conclusions) It was stated that the further development of the agro-industrial complex facilities is associated with an increase in the level of energy supply, reliability, energy efficiency and environmental friendliness of power supply systems through the introduction of modern distributed generation systems based on traditional, renewable and combined sources of electricity.

Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.

"Neuroethics, National Security and Secrecy." The American Journal of Bioethics, 7(5), pp. 14–15 The intramural program of the National Institute of Environmental Health Sciences, National Institutes of Health, sponsored this research. It does not represent the views of the National Institute of Environmental Health Sciences or the National Institutes of Health.

Scientists at Jefferson Medical College and the Kimmel Cancer Center at Thomas Jefferson University in Philadelphia have found how a gene can dim the power production in the cell and in turn scale up its cancer-producing activities.Two new studies provide stunning evidence suggesting that cyclin D1 - which is found in up to eight times normal amounts in half of all breast cancers - can cause a shift in the cancer cell's metabolism, changing its focus from energy production to proliferation. The findings, they say, may point to new therapeutic strategies against cancer.Reporting in July, 2006 in the journal Molecular and Cellular Biology, Kimmel Cancer Center director Richard G. Pestell, M.D., Ph.D., Professor and Chair of the Department of Cancer Biology at Jefferson Medical College, and colleagues showed for the first time that cyclin D1 - normally involved in promoting cell division - inhibits the size and activity of the cell's energy-making mitochondria. In a separate report in August, 2006 in the Proceedings of the National Academy of Sciences (PNAS), Dr. Pestell and a different team identified the mechanism behind cyclin D1's mitochondrial takeover. The research, taken together, shows that the inhibition leads to increased proliferation of cancer cells."From the cancer cell's point of view, the inhibition allows the cell to shift its biosynthetic priorities - it allows it to shift from making mitochondria themselves to synthesizing DNA and making the cell proliferate," says Dr. Pestell."Cyclin D1 shifts the individual cell's metabolism away from making mitochondria and towards cellular proliferation and the various genes involved in promoting such proliferation," he says.The mitochondria often are called the "powerhouse" of the cell because they produce about 90 percent of the body's energy. They are located in the cytoplasm outside of each cell's nucleus.Dr. Pestell notes that scientists have long suspected a link between mitochondrial malfunction and cancer, and since 1930 have known about such a change in metabolism when the cell turns cancerous. But the mechanisms haven't been well understood. When cells turn cancerous, they shift the way they metabolize glucose and other substrates. The researchers believe that their findings about cyclin D1 are part of such a mechanism. "These changes were observed previously," he says. "Now we know that the same factor that is involved in causing breast cancer also directly causes a metabolic shift."I. Bernard Weinstein, M.D., Frode Jensen Professor of Medicine at Columbia University, notes that the 1930 discovery that the function of mitochondria is often impaired in cancer cells has remained unexplained and cancer research has been mainly focused on abnormalities in the function of genes in the nucleus of cells. Thework by Dr. Pestell's group "provides novel insights into how these two types of abnormalities in cancer cells might be related."In the PNAS publication, Dr. Pestell's team found that a protein, nuclear respiratory factor-1 (NRF-1), regulates a gene called mtTFA and is essential for mitochondrial function. To make mitochondria, then, NRF-1 turns on mtTFA, which then activates genes that produce mitochondria. Cyclin D1 inactivates NRF-1, halting production."This discovery advances our understanding of the behavior of cancer cells and may suggest new types of cancer therapy," Dr. Weinstein says.Dr. Pestell notes that such metabolic changes should leave the cancer cell vulnerable. "We'd like to link that change in metabolism to therapies," he says. "We've been able to prove that we can see changes in metabolism in the breast, and we should be able to target that change and kill the cancerous cells." He explains that specialists can image tumors based on changes in metabolism.The results could also "provide a mechanism for targeting the mitochondria, rather than the nucleus," he says, noting that cancer drugs usually target nuclear genes. "Importantly, they provide a direct link between the mitochondria and the nucleus - one gene regulating both compartments of the cell. We didn't know whatcoordinated both functions. This shows both are functionally linked by a common gene.""If we have therapies that target changes in metabolism, it allows us to develop therapies selective for the cancerous cells only," says Dr. Pestell.

Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.

Tonic inhibition in mouse hippocampal CA1 pyramidal neurons is mediated by α5 subunit-containing γ-aminobutyric acid type A receptors. By Caraiscos VB, Elliott EM, You-Ten KE, Cheng VY, Belelli D, Newell JG, Jackson MF, Lambert JJ, Rosahl TW, Wafford KA, MacDonald JF, Orser BA. Proc Natl Acad Sci U S A 2004; 101:3662-7. Reprinted with permission. In this Classic Paper Revisited, the author recounts the scientific journey leading to a report published in the Proceedings of the National Academy of Sciences (PNAS) and shares several personal stories from her formative years and "research truths" that she has learned along the way. Briefly, the principal inhibitory neurotransmitter in the brain, γ-aminobutyric acid (GABA), was conventionally thought to regulate cognitive processes by activating synaptic GABA type A (GABAA) receptors and generating transient inhibitory synaptic currents. However, the author's laboratory team discovered a novel nonsynaptic form of tonic inhibition in hippocampal pyramidal neurons, mediated by extrasynaptic GABAA receptors that are pharmacologically distinct from synaptic GABAA receptors. This tonic current is highly sensitive to most general anesthetics, including sevoflurane and propofol, and likely contributes to the memory-blocking properties of these drugs. Before the publication in PNAS, the subunit composition of GABAA receptors that generate the tonic current was unknown. The team's research showed that GABAA receptors containing the α5 subunit (α5GABAARs) generated the tonic inhibitory current in hippocampal neurons. α5GABAARs are highly sensitive to GABA, desensitize slowly, and are thus well suited for detecting low, persistent, ambient concentrations of GABA in the extracellular space. Interest in α5GABAARs has surged since the PNAS report, driven by their pivotal roles in cognitive processes and their potential as therapeutic targets for treating various neurologic disorders.

Starting in 2005, the new open-access (or free-access) edition of the Proceedings of the National Academy of Sciences (PNAS) will include an institutional membership automatically with every institutional site license. The memberships will give authors from those institutions a 25% discount on the $1,000 processing fee PNAS charges to publish an accepted article.

Around the world, countries face a number of concerns about electricity production, including greenhouse gas emissions, air pollution, reliance on foreign energy sources, and adequacy of supply. In order to address these concerns, governments have increasingly attempted to foster the development of so-called ‘new’ renewable sources of electricity: geothermal, solar, wind, and tidal or wave power. Although generation of electricity from these energy sources still accounts for a minuscule percentage of global electricity production,1 growth rates in energy supplied by these sources (particularly solar and wind) since 1971 greatly exceed growth rates for other sources of energy.2 More importantly, the use of new renewable source electricity varies considerably among different countries, suggesting that public policies can have a significant impact on the development and diffusion of renewable energy technologies.3 In order to encourage the production of electricity from these new renewable sources, governments have attempted to rely on various kinds of policy measures. In some countries, environmentally-related taxes like the United Kingdom’s Climate Change Levy operate to discourage the use of non-renewable energy and thereby encourage the production of electricity from new renewable sources. Other countries have sought to encourage the development of new sources of renewable energy through subsidies in the form of direct grants or low-interest loans or tax-delivered subsidies in the form of deductions or credits. Yet other jurisdictions have established guaranteed prices or ‘feed-in tariffs’ at which renewable energy can be sold to electricity distributors, or have adopted ‘renewable portfolio standards’ specifying that electricity distributors must obtain a stipulated quantity or percentage of electricity from renewable sources within specified periods. In addition to these measures, the development of new renewable energy sources has also been encouraged through voluntary targets for production or consumption. Not surprisingly, perhaps, most countries employ several of these instruments.

The deposited data sets contain:
\n
\n1) Simulated spike trains from a network of interacting neurons
\n2) Two-photon calcium imaging data from the mouse auditory cortex (Kanold Lab, UMD)
\n3) Single-unit spike data from the ferret auditory and prefrontal cortices (Neural Systems Lab, UMD)
\n
\nPlease refer to readme.txt for further details. These data are used in the following article:
\n
\nA. Sheikhattar, S. Miran, J. Liu, J. B. Fritz, S. A. Shamma, P. O. Kanold, and B. Babadi (2018). Extracting neuronal functional network dynamics via adaptive Granger causality analysis, Proceedings of the National Academy of Sciences (PNAS), 2018 (www.pnas.org/cgi/doi/10.1073/pnas.1718154115)
\n
\nand are disseminated for public use in the spirit of easing reproducibility. The MATLAB implementation of the algorithms used in this work are deposited on Github at https://github.com/Arsha89/AGC Analysis.

The rapid deployment of renewable sources of electricity (RES-E) is transforming power systems globally. This trend is likely to continue with large increases in investment and deployment of RES-E capacity over the coming decades. Several countries now have penetration levels of variable RES-E generation (i.e., wind and solar) in excess of 15% of their annual electricity generation; and many jurisdictions (e.g., Spain, Portugal, Ireland, Germany, and Denmark; and, in the United States, Colorado) have experienced instantaneous penetration levels of more than 50% variable generation.1 These penetration levels of variable RES-E have prompted many jurisdictions to begin modifying practices that evolved in an era of readily dispatchable, centralised power systems. Providing insights for the transition to high levels of variable RES-E generation is the focus of this document, which is the final report of the RES-E-NEXT project commissioned by the International Energy Agency’s implementing agreement on Renewable Energy Technology Deployment (IEA-RETD). It presents a comprehensive assessment of issues that will shape power system evolution during the transition to high levels of variable RES-E generation. While policy will be a central tool to sustain the growth of RES-E capacity and to enable power system transitions, the scope of the report extends beyond policy considerations to include the related domains of regulation, power market design, and system operation protocols. This broad scope is in recognition that a changing resource mix with greater penetration levels of variable RES-E has broad implications for grid operations, wholesale and retail power markets, and infrastructure needs. The next decade will be a critical transition period for power system stakeholders, as global deployment of RES-E capacity (and especially variable RES-E capacity) continues to scale-up in many regions of the world. To address increased penetration levels of RES-E in power systems and the new challenges that could emerge, coordinated portfolios of policies, market designs, regulations, and operational protocols are essential. The goal for policymakers is to facilitate investment in RES-E technologies and to enable efficient and reliable system operation, costeffective service delivery, and continued public acceptance. Although the factors that impact the speed and scale of RES-E deployment manifest uniquely in each power system, in the transition to high shares of variable RES-E this report identifies four critical domains and the changing drivers that will shape next-generation policy for each. These domains are introduced in Table I, and comprise the major sections of this report.