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oxygen evolution

Duan Bin, Ziyang Guo, Andebet Gedamu Tamirat, Yuanyuan Ma, Yonggang Wang, Yongyao Xia
The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are traditionally carried out using noble metals (such as Pt) and metal oxides (such as RuO2 and IrO2) as catalysts, respectively. Nevertheless, several key issues such as high cost, poor stability, and detrimental environmental effects limit the catalytic activity of these noble metal- and metal oxide-based catalysts. Herein, we have designed and synthesized macroporous carbon nanofiber arrays by using a natural crab shell template. Subsequently, spinel MnCo2O4 nanoparticles were embedded into the nitrogen-doped macroporous carbon nanofiber arrays (NMCNAs) by a hydrothermal method...
July 27, 2017: Nanoscale
Jaemin Kim, Pei-Chieh Shih, Kai-Chieh Tsao, Yung-Tin Pan, Xi Yin, Cheng-Jun Sun, Hong Yang
Development of acid-stable electrocatalysts with low overpotential for oxygen evolution reaction (OER) is a major challenge to produce of hydrogen directly from water. We report in this paper a pyrochlore yttrium ruthenate (Y2Ru2O7-δ) electrocatalyst that has significantly enhanced performance towards OER in acid media over the best-known catalysts, with an onset overpotential of 190 mV and high stability in 0.1-M perchloric acid solution. X-ray absorption near-edge structure (XANES) indicates Y2Ru2O7-δ electrocatalyst had a low valence state that favors the high OER activity...
July 27, 2017: Journal of the American Chemical Society
Yujin Ji, Huilong Dong, Mingye Yang, Tingjun Hou, Youyong Li
The development of novel cathode catalysts is of great importance to the practical applications of nonaqueous lithium oxygen (Li-O2) batteries. Here by using first-principles calculations, we revealed the catalytic mechanism and evaluated the catalytic activity of monolayer germanium monochalcogenides (2D-GeXs, X = S/Se) as cathode catalytic materials. For 2D-GeXs, Li4O4 with a ring-like structure is the final discharge product. The free energy diagram demonstrates that 2D-GeSe is more energetically favorable than 2D-GeS due to its considerably lower oxygen reduction reaction (ORR) overpotential (0...
July 27, 2017: Physical Chemistry Chemical Physics: PCCP
Ammar Bin Yousaf, M Imran, Syed Javaid Zaidi, Peter Kasak
The demand for clean renewable energy is increasing due to depleting fossil fuels and environmental concerns. Photocatalytic hydrogen production through water splitting is one such promising route to meet global energy demands with carbon free technology. Alternative photocatalysts avoiding noble metals are highly demanded. Herein, we fabricated heterostructure consist of oxygen-deficient WO3-x nanorods with Zn0.3Cd0.7S nanoparticles for an efficient Z-Scheme photocatalytic system. Our as obtained heterostructure showed photocatalytic H2 evolution rate of 352...
July 26, 2017: Scientific Reports
Chongyi Ling, Li Shi, Yixin Ouyang, Xiao Cheng Zeng, Jinlan Wang
Nanosheet supported single-atom catalysts (SACs) can make full use of metal atoms and yet entail high selectivity and activity, while bifunctional catalysts can enable higher performance while lowering the cost than two separated unifunctional catalysts. Supported single-atom bifunctional catalysts are therefore of great economic interest and scientific importance. Here, based on first-principles computations, we report a design of the first single-atom bifunctional eletrocatalyst, namely, isolated nickel atom supported on β12 boron monolayer (Ni1/β12-BM), to achieve overall water splitting...
July 26, 2017: Nano Letters
Haoyi Li, Shuangming Chen, Haifeng Lin, Xiaobin Xu, Haozhou Yang, Li Song, Xun Wang
Well-designed hybrid materials based on noble metal-free elements have great potential to generate hydrogen (H2 ) and oxygen (O2 ) sustainably via overall water splitting for developing practical energy-related technologies. Herein, an accessible method is presented to synthesize nickel diselenide (NiSe2 ) ultrathin nanowires decorated with amorphous nickel oxide nanoparticles (NiOx NPs) as multifunctional electrocatalysts (NSWANs) for hydrogen and oxygen evolution reaction (HER and OER). The NSWANs exhibit quite low HER and OER overpotentials of 174 and 295 mV, respectively, holding the current density of 20 mA cm(-2) for 24 h continuous operations in alkaline media...
July 26, 2017: Small
J Gracia
The technological interest of oxygen reduction and evolution reactions, ORR and OER, for the clean use and storage of energy has resulted in the discovery of multiple catalysts; and the physical and catalytic properties of the most active compositions are only comprehensible with the consideration of magnetic interactions. Spin dependent potentials via exchange interactions, spin-orbit coupling or through magneto-electric effects catalyse the oxygen electrochemistry. The best catalysts show metal sites with localized spins and electron delocalization; a correlation exists between the rate constant for charge transfer reactions and spin-dependent electron mobility...
July 26, 2017: Physical Chemistry Chemical Physics: PCCP
Qing Zhao, Zhenhua Yan, Chengcheng Chen, Jun Chen
Spinels with the formula of AB2O4 (where A and B are metal ions) and the properties of magnetism, optics, electricity, and catalysis have taken significant roles in applications of data storage, biotechnology, electronics, laser, sensor, conversion reaction, and energy storage/conversion, which largely depend on their precise structures and compositions. In this review, various spinels with controlled preparations and their applications in oxygen reduction/evolution reaction (ORR/OER) and beyond are summarized...
July 26, 2017: Chemical Reviews
Sandra Haschke, Dmitrii Pankin, Yuri Petrov, Sebastian Bochmann, Alina Manshina, Julien Bachmann
Nanotubular iron(III) oxide electrodes are optimized for catalytic proficiency in the water oxidation reaction at neutral pH. Nanostructured electrodes are prepared from anodic alumina templates coated with Fe2O3 by atomic layer deposition. Scanning helium ion microscopy, X-ray diffraction and Raman spectroscopy characterize the morphology and phase of samples submitted to various treatments. These methods document the contrasting effects of thermal annealing, on the one hand, and of electrochemical treatment, on the other hand...
July 26, 2017: ChemSusChem
Congling Hu, Lei Zhang, Zhi-Jian Zhao, Jun Luo, Jing Shi, Zhiqi Huang, Jinlong Gong
Transition-metal oxides are extensively investigated as efficient electrocatalysts for the oxygen evolution reaction (OER). However, large-scale applications remain challenging due to their moderate catalytic activity. Optimized regulation of surface states can lead to improvement of catalytic properties. Here, the design of Mn@Cox Mn3-x O4 nanoparticles with abundant edge sites via a simple seed-mediated growth strategy is described. The unsaturated coordination generated on the edge sites of Cox Mn3-x O4 shells makes a positive contribution to the surface-structure tailoring...
July 26, 2017: Advanced Materials
Lauren K Yum, Sebastian Baumgarten, Till Röthig, Cornelia Roder, Anna Roik, Craig Michell, Christian R Voolstra
Despite the importance of deep-sea corals, our current understanding of their ecology and evolution is limited due to difficulties in sampling and studying deep-sea environments. Moreover, a recent re-evaluation of habitat limitations has been suggested after characterization of deep-sea corals in the Red Sea, where they live at temperatures of above 20 °C at low oxygen concentrations. To gain further insight into the biology of deep-sea corals, we produced reference transcriptomes and studied gene expression of three deep-sea coral species from the Red Sea, i...
July 25, 2017: Scientific Reports
Yue Lu, Jiguo Geng, Kuan Wang, Wei Zhang, Wenqiang Ding, Zhenhua Zhang, Shaohua Xie, Hongxing Dai, Fu-Rong Chen, Manling Sui
Dissolution of metal oxides is fundamentally important for understanding mineral evolution and micromachining oxide functional materials. In general, dissolution of metal oxides is a slow and inefficient chemical reaction. Here, by introducing oxygen deficiencies to modify the surface chemistry of oxides, we can boost the dissolution kinetics of metal oxides in water, as in situ demonstrated in a liquid environmental transmission electron microscope (LETEM). The dissolution rate constant significantly increases by 16-19 orders of magnitude, equivalent to a reduction of 0...
July 27, 2017: ACS Nano
Ruquan Ye, Yieu Chyan, Jibo Zhang, Yilun Li, Xiao Han, Carter Kittrell, James M Tour
Wood as a renewable naturally occurring resource has been the focus of much research and commercial interests in applications ranging from building construction to chemicals production. Here, a facile approach is reported to transform wood into hierarchical porous graphene using CO2 laser scribing. Studies reveal that the crosslinked lignocellulose structure inherent in wood with higher lignin content is more favorable for the generation of high-quality graphene than wood with lower lignin content. Because of its high electrical conductivity (≈10 Ω per square), graphene patterned on wood surfaces can be readily fabricated into various high-performance devices, such as hydrogen evolution and oxygen evolution electrodes for overall water splitting with high reaction rates at low overpotentials, and supercapacitors for energy storage with high capacitance...
July 24, 2017: Advanced Materials
Tung Ngoc Pham, Tiva Sharifi, Robin Sandström, William Siljebo, Andrey Shchukarev, Krisztian Kordas, Thomas Wågberg, Jyri-Pekka Mikkola
Herein we report a 3D heterostructure comprising a hierarchical macroporous carbon foam that incorporates mesoporous carbon nanotubes decorated with cobalt oxide nanoparticles as an unique and highly efficient electrode material for the oxygen evolution reaction (OER) in electrocatalytic water splitting. The best performing electrode material showed high stability after 10 h, at constant potential of 1.7 V vs. RHE (reversible hydrogen electrode) in a 0.1 M KOH solution and high electrocatalytic activity in OER with low overpotential (0...
July 21, 2017: Scientific Reports
Graham Noctor, Jean-Philippe Reichheld, Christine H Foyer
As sessile oxygenic organisms with a plastic developmental programme, plants are uniquely positioned to exploit reactive oxygen species (ROS) as powerful signals. Plants harbor numerous ROS-generating pathways, and these oxidants and related redox-active compounds have become tightly embedded into plant function and development during the course of evolution. One dominant view of ROS-removing systems sees them as beneficial antioxidants battling to keep damaging ROS below dangerous levels. However, it is now established that ROS are a necessary part of subcellular and intercellular communication in plants and that some of their signaling functions require ROS-metabolizing systems...
July 18, 2017: Seminars in Cell & Developmental Biology
Luc De Vuyst, Simon Van Kerrebroeck, Frédéric Leroy
From a microbiological perspective, sourdough is to be considered as a specific and stressful ecosystem, harboring yeasts and lactic acid bacteria (LAB), that is used for the production of baked goods. With respect to the metabolic impact of the sourdough microbiota, acidification (LAB), flavor formation (LAB and yeasts), and leavening (yeasts and heterofermentative LAB species) are most noticeable. Three distinct types of sourdough fermentation processes can be discerned based on the inocula applied, namely backslopped ones (type 1), those initiated with starter cultures (type 2), and those initiated with a starter culture followed by backslopping (type 3)...
2017: Advances in Applied Microbiology
Saeid Masudy-Panah, Roozbeh Siavash Moakhar, Chin Sheng Chua, Ajay Kumar Kushwaha, Goutam Kumar Dalapati
Enhancing stability against photo-corrosion and improving photocurrent response are the main challenges toward the development of cupric oxide (CuO) based photocathodes for solar-driven hydrogen production. In this paper, stable and efficient CuO-photocathodes have been developed using in-situ materials engineering and through gold-palladium (Au-Pd) nanoparticles deposition on the CuO surface. The CuO photocathode exhibits a photocurrent generation of ~3 mA/cm2 at 0V v/s RHE. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis and X-ray spectroscopy (XPS) confirm the formation of oxygen-rich (O-rich) CuO film which demonstrate highly stable photocathode with retained photocurrent of ~90% for 20 minutes...
July 21, 2017: ACS Applied Materials & Interfaces
Hongwei Huang, Shuchen Tu, Chao Zeng, Tierui Zhang, A H Reshak, Yihe Zhang
We report that both efficient photo- and piezoelectric- induced molecular oxygen activation are achieved via macroscopic polarization enhancement on a noncentrosymmetric piezoelectric semiconductor BiOIO3. The replacement of V5+ ions for I5+ in IO3 polyhedra gives rise to strengthened macroscopic polarization of BiOIO3, which facilitates the charge separation in the photocatalytic and piezoelectric-catalytic process, and renders largely promoted photo- and piezoelectric induced reactive oxygen species (ROS) evolution, such as superoxide radicals (*O2-) and hydroxyl radicals (*OH)...
July 21, 2017: Angewandte Chemie
Martin Havlicek, Dimo Ivanov, Benedikt A Poser, Kamil Uludag
The blood oxygenation level-dependent (BOLD) fMRI response to neuronal activation results from a complex interplay of induced metabolic and vascular changes. Thus, its transients, such as initial overshoot and post-stimulus undershoot, provide a window into the dynamic relationships of the underlying physiological variables. In this study, we propose multi-echo fMRI as a tool to investigate the physiological underpinnings of the BOLD signal, in particular, and brain functional physiology, in general. In the human visual cortex at 3 T, we observed that the BOLD response is nonlinearly dependent on echo-time (TE) and the amount of nonlinearity varies during the entire time-course...
July 17, 2017: NeuroImage
Jessica M Moore, Raul Correa, Susan M Rosenberg, P J Hastings
Bacteria, yeast and human cancer cells possess mechanisms of mutagenesis upregulated by stress responses. Stress-inducible mutagenesis potentially accelerates adaptation, and may provide important models for mutagenesis that drives cancers, host pathogen interactions, antibiotic resistance and possibly much of evolution generally. In Escherichia coli repair of double-strand breaks (DSBs) becomes mutagenic, using low-fidelity DNA polymerases under the control of the SOS DNA-damage response and RpoS general stress response, which upregulate and allow the action of error-prone DNA polymerases IV (DinB), II and V to make mutations during repair...
July 20, 2017: PLoS Genetics
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