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oxygen evolution

Si Xuan She, Jie Yu, Wan Qi Tang, Yinlong Zhu, Yu Bo Chen, Jaka Sunarso, Wei Zhou, Zongping Shao
Perovskite oxide is an attractive low-cost alternative catalyst for oxygen evolution reaction (OER) relative to the precious metal oxide-based eletrocatalysts (IrO2 and RuO2). In this work, a series of Sr-doped La-based perovskite oxide catalysts with compositions of La1-xSrxFeO3-δ (x = 0, 0.2, 0.5, 0.8, and 1) are synthesized and characterized. The OER specific activities in alkaline solution increase in the order of LaFeO3-δ (LF), La0.8Sr0.2FeO3-δ (LSF-0.2), La0.5Sr0.5FeO3-δ (LSF-0.5), SrFeO3-δ (SF) and La0...
March 16, 2018: ACS Applied Materials & Interfaces
Peter L Cummins, Babu Kannappan, Jill E Gready
The ubiquitous enzyme Ribulose 1,5-bisphosphate carboxylase-oxygenase (RuBisCO) fixes atmospheric carbon dioxide within the Calvin-Benson cycle that is utilized by most photosynthetic organisms. Despite this central role, RuBisCO's efficiency surprisingly struggles, with both a very slow turnover rate to products and also impaired substrate specificity, features that have long been an enigma as it would be assumed that its efficiency was under strong evolutionary pressure. RuBisCO's substrate specificity is compromised as it catalyzes a side-fixation reaction with atmospheric oxygen; empirical kinetic results show a trend to tradeoff between relative specificity and low catalytic turnover rate...
2018: Frontiers in Plant Science
Kavita M Jeerage, Stephanie L Candelaria, Samuel M Stavis
Electrocatalytic core-shell nanoparticles, such as nickel/iron oxides for the oxygen evolution reaction (OER) in alkaline electrolytes, require rapid synthesis and measurement for practical use. To meet this challenge, we investigated a novel process of adding Ni(II) species to Fe nanoparticles immediately after synthesis, which we expected to yield Ni-rich shells around Fe-rich cores. Cyclic voltammetry showed that the overpotential decreased as the molar ratio of Ni to Fe in the synthesis vessel increased from 0...
March 15, 2018: Scientific Reports
Andrew Best, Jason M Kamilar
Sweating is an unusual thermoregulatory strategy for most mammals, yet is critical for humans. This trait is commonly hypothesized to result from human ancestors moving from a forest to a warmer and drier open environment. As soft tissue traits do not typically fossilize, this idea has been difficult to test. Therefore, we used a comparative approach to examine 15 eccrine gland traits from 35 primate species. For each trait we measured phylogenetic signal, tested three evolutionary models to explain trait variation, and used phylogenetic models to examine how traits varied in response to climate variables...
April 2018: Journal of Human Evolution
Da Wei Zhang, Jing Wei Li, Jia Xian Luo, Pei Man Xu, Li Cheng Wei, Dan Zhou, Wei Ming Xu, Dingsheng Yuan
It is essential to synthesize low-cost, earth-abundant bifunctional electrocatalysts
 for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for
 water electrolysis. Herein, we present a one-step sulfurization method to fabricate
 Ni3S2 nanowires directly grown on Ni foam (Ni3S2 NWs/Ni) as such an electrocatalyst.
 This synthetic strategy has several advantages including facile preparation, low cost
 and even can be expanded to large-scale preparation in the practical application...
March 15, 2018: Nanotechnology
Nika Mahne, Sara E Renfrew, Bryan D McCloskey, Stefan A Freunberger
Solid alkaline carbonates are universal passivation layer components of intercalation battery materials, common side products in metal-O₂ batteries, and are believed to form and decompose reversibly in metal-O₂/CO₂ cells. In all of these cathode chemistries, Li₂CO₃ decomposes to CO₂ when exposed to potentials >3.8 V vs. Li/Li+. Notably, though, O₂ evolution is not detected, as is expected according to the decomposition reaction 2 Li₂CO₃ → 4 Li+ + 4 e- + 2 CO₂ + O₂. O-moieties were therefore previously considered unaccounted for in unidentified parasitic reactions...
March 15, 2018: Angewandte Chemie
Sulagna Patnaik, Gayatri Swain, K M Parida
Herein, a novel Cu-MoO3 /g-C3 N4 hybrid nanocomposite was successfully synthesized by a two-step strategy of one-pot pyrolysis followed by the impregnation method. The structure, phase, morphology and electronic environment of MoO3 , g-C3 N4 and Cu in the composite were determined by various characterization methods. The oxygen vacancies of MoO3 were ascertained by UV-DRS, Raman, and XPS analysis. The formation of the heterostructure was characterised by electrochemical measurements. The photocatalytic performance of the composite was investigated by the water reduction reaction and the reduction of an important inorganic pollutant, Cr(vi)...
March 15, 2018: Nanoscale
Jinlong Liu, Yao Zheng, Yan Jiao, Zhenyu Wang, Zhouguang Lu, Anthony Vasileff, Shi-Zhang Qiao
Conventional development of nanomaterials for efficient electrocatalysis is largely based on performance-oriented trial-and-error/iterative approaches, while a rational design approach at the atomic/molecular level is yet to be found. Here, inspired by a fundamental understanding of the mechanism for both oxygen and hydrogen evolution half reactions (OER/HER), a unique strategy is presented to engineer RuO2 for superior alkaline water electrolysis through coupling with NiO as an efficient bifunctional promoter...
March 15, 2018: Small
Marcin Czarnoleski, Anna Maria Labecka, Dominika Dragosz-Kluska, Tomasz Pis, Katarzyna Pawlik, Filip Kapustka, Wincenty M Kilarski, Jan Kozłowski
Cell size plays a role in body size evolution and environmental adaptations. Addressing these roles, we studied body mass and cell size in Galliformes birds and Rodentia mammals and collected published data on their genome sizes. In birds, we measured erythrocyte nuclei and basal metabolic rates (BMRs). In birds and mammals, larger species consistently evolved larger cells for five cell types (erythrocytes, enterocytes, chondrocytes, skin epithelial cells, and kidney proximal tubule cells) and evolved smaller hepatocytes...
March 14, 2018: Biology Open
Bo You, Yujie Sun
Electrocatalytic water splitting driven by renewable energy input to produce clean H2 has been widely viewed as a promising strategy of the future energy portfolio. Currently, the state-of-the-art electrocatalysts for water splitting in acidic solutions are IrO2 or RuO2 for the O2 evolution reaction (OER) and Pt for the H2 evolution reaction (HER). Realization of large-scale H2 production from water splitting requires competent nonprecious electrocatalysts. Despite the advances of decades in this field, several challenges still exist and need to be overcome: (1) Most efforts in the design of nonprecious electrocatalysts have focused on developing HER catalysts for acidic conditions but OER catalysts for alkaline conditions owing to their thermodynamic convenience, potentially resulting in incompatible integration of the two types of catalysts and thus inferior overall performance...
March 14, 2018: Accounts of Chemical Research
Chun Xian Guo, Chang Ming Li
Unique room temperature-formed iron-doped nickel hydroxide on Ni foam as a 3D electrode in alkaline electrolyte offers fast gas dissipation, a high number of active sites and a high oxidation state of Ni for an improved oxidation ability for the oxygen evolution reaction (OER), which delivers an OER current density of 100 mA cm-2 at an overpotential of 0.312 V and 96.3% retention after 100 h at an overpotential of 0.370 V in 1 M KOH, and 1000 mA cm-2 at an overpotential of 0.265 V in 30 wt% KOH.
March 14, 2018: Chemical Communications: Chem Comm
Yali Ma, Yu Zhang, Xue Wang, Meihong Fan, Kaiqian Li, Tao Wang, Yunling Liu, Qisheng Huo, Zhen-An Qiao, Sheng Dai
With unique physical and chemical properties and porous architectures, mesoporous transition metal hydroxide (MMHO) and oxide (MMO) nanospheres hold great potential for various applications in drug delivery, catalysis, energy storage and conversion. However, synthesizing MMHO and MMO with well-defined mesostructures remains a great challenge because of the weak interaction between surfactants and metal precursors. Herein we describe a chelation-induced cooperative self-assembly system in which the weak interaction can be cooperatively amplified through the use of a chelating ligand acting as a co-template...
March 14, 2018: Nanoscale
Lucie Sauzéat, Anne Laurençon, Vincent Balter
Ageing is accompanied by important chemical deregulations resulting in bodily metal imbalances. The way and extent to which these deregulations are associated with ageing processes are however poorly understood and their use as potential biomarkers of ageing has not been investigated. In this study, we report whole-body elementary concentrations and copper and zinc isotopic compositions of Caenorhabditis elegans in ageing wild type (i.e. 'normal'-lived) and mutant (i.e. short and long-lived) strains. We show that the strains are characterized by different levels of mutation-related variations such as in phosphorus and magnesium as well as in zinc isotopic composition...
March 14, 2018: Metallomics: Integrated Biometal Science
Jiong Wang, Liyong Gan, Wenyu Zhang, Yuecheng Peng, Hong Yu, Qingyu Yan, Xinghua Xia, Xin Wang
Molecularly well-defined Ni sites at heterogeneous interfaces were derived from the incorporation of Ni2+ ions into heteroatom-doped graphene. The molecular Ni sites on graphene were redox-active. However, they showed poor activity toward oxygen evolution reaction (OER) in KOH aqueous solution. We demonstrated for the first time that the presence of Fe3+ ions in the solution could bond at the vicinity of the Ni sites with a distance of 2.7 Å, generating molecularly sized and heterogeneous Ni-Fe sites anchored on doped graphene...
March 2018: Science Advances
Indrani Mukherjee, Ross R Large, Ross Corkrey, Leonid V Danyushevsky
The period 1800 to 800 Ma ("Boring Billion") is believed to mark a delay in the evolution of complex life, primarily due to low levels of oxygen in the atmosphere. Earlier studies highlight the remarkably flat C, Cr isotopes and low trace element trends during the so-called stasis, caused by prolonged nutrient, climatic, atmospheric and tectonic stability. In contrast, we suggest a first-order variability of bio-essential trace element availability in the oceans by combining systematic sampling of the Proterozoic rock record with sensitive geochemical analyses of marine pyrite by LA-ICP-MS technique...
March 13, 2018: Scientific Reports
Valeri Petkov, Yazan Maswadeh, Aolin Lu, Shiyao Shan, Haval Kareem, Yinguang Zhao, Jin Luo, Chuan-Jian Zhong, Kevin Beyer, Karena W Chapman
We present results from combined in situ infrared spectroscopy and total x-ray scattering studies on the evolution of catalytically active sites in exemplary binary and ternary Pt-based nanoalloys during a sequence of CO oxidation-reactivation-CO oxidation reactions. We find that, when within a particular compositional range, the fresh nanoalloys may exhibit high catalytic activity for low-temperature CO oxidation. Using surface-specific atomic pair distribution functions (PDFs) extracted from the in situ total x-ray scattering data we find that, regardless their chemical composition and initial catalytic activity, the fresh nanoalloys suffer a significant surface structural disorder during CO oxidation...
March 13, 2018: ACS Applied Materials & Interfaces
Janelle Yorke, Christi Deaton, Malcolm Campbell, Linda McGowen, Paul Sephton, David G Kiely, Iain Armstrong
Introduction: The aim of this cohort study was to examine health-related quality of life (HRQoL) and symptomatology in patients with pulmonary hypertension (PH) and explore factors that influence its evolution over time. Methods: A prospective longitudinal multisite cohort study. Participants were recruited from specialist UK PH centres and completed a questionnaire pack at baseline, 6, 12 and 18 months to assess HRQoL (emPHasis-10), dyspnoea, fatigue, sleep, anxiety and depression...
2018: BMJ Open Respiratory Research
Tong Tong, Si Chen, Lianrong Wang, You Tang, Jae Yong Ryu, Susu Jiang, Xiaolin Wu, Chao Chen, Jie Luo, Zixin Deng, Zhiqiang Li, Sang Yup Lee, Shi Chen
The chemical diversity of physiological DNA modifications has expanded with the identification of phosphorothioate (PT) modification in which the nonbridging oxygen in the sugar-phosphate backbone of DNA is replaced by sulfur. Together with DndFGH as cognate restriction enzymes, DNA PT modification, which is catalyzed by the DndABCDE proteins, functions as a bacterial restriction-modification (R-M) system that protects cells against invading foreign DNA. However, the occurrence of dnd systems across a large number of bacterial genomes and their functions other than R-M are poorly understood...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
Penglun Zheng, Yu Zhang, Zhengfei Dai, Yun Zheng, Khang Ngoc Dinh, Jun Yang, Raksha Dangol, Xiaobo Liu, Qingyu Yan
Heterostructures have attracted increasing attention due to their amazing synergetic effects, which may improve the electrochemical properties, such as good electrical/ionic conductivity, electrochemical activity, and mechanical stability. Herein, novel hierarchical Fe2 O3 @Ni3 Se4 nanotubes are successfully fabricated by a multistep strategy. The nanotubes show length sizes of ≈250-500 nm, diameter sizes of ≈100-150 nm, and wall thicknesses of ≈10 nm. The as-prepared Fe2 O3 @Ni3 Se4 nanotubes with INi:Fe = 1:10 show excellent Li storage properties (897 mAh g-1 high reversible charge capacity at 0...
March 12, 2018: Small
Yuan Zhao, Shengbo Zhang, Mengyun Wang, Jinyu Han, Hua Wang, Zhongcheng Li, Xiao Liu
Intensive efforts have been made towards designing water oxidation catalysts using homogeneous metal complexes. However, poor stability, caused by structure collapse and strong oxidants, prohibits further application of these catalysts. Therefore, the fabrication of stable and efficient water oxidation catalysts with robust structures and mild driving forces is in high demand. In this paper, we demonstrate the heterogeneous, porous and stable structure of Ir-doped metal organic frameworks (MOFs) by functionalizing bipyridine-incorporated MOFs with [IrCp*Cl(μ-Cl)]2 complexes...
March 12, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
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