scholarly journals Two-sites are better than one: revisiting the OER mechanism on CoOOH by DFT with electrode polarization

2020 ◽  
Vol 22 (13) ◽  
pp. 7031-7038 ◽  
Author(s):  
Antton Curutchet ◽  
Pauline Colinet ◽  
Carine Michel ◽  
Stephan N. Steinmann ◽  
Tangui Le Bahers
Keyword(s):  
Water Oxidation ◽  
Electrode Polarization ◽  
Electrode Polarisation ◽  
Competitive Mechanisms ◽  
Step Mechanism ◽  
Better Than

We uncover several competitive mechanisms of water oxidation on the β-CoOOH (10–14) surface by explicitly including electrode polarisation and going beyond the classical 4-step mechanism frequently used to study this reaction at the DFT level.

scholarly journals Modulation of Mo-Fe-C sites over mesoscale diffusion-enhanced hollow sub-micro reactors toward boosted electrochemical water oxidation

2021 ◽  
Author(s):  
Feilong Gong ◽  
Mengmeng Liu ◽  
Lihua Gong ◽  
Sheng Ye ◽  
Qike Jiang ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Theoretical Calculations ◽  
Single Atom ◽  
Element Simulation ◽  
The Stability ◽  
Micro Reactors ◽  
Kinetics Of ◽  
Micro Reactor ◽  
Better Than ◽  
Diffusion Properties

Abstract Simultaneously engineering the mesoscale mass transfer and surface reactions on the electrode can promote the kinetics of oxygen evolution reaction (OER). Herein, we report the simultaneously modulation of the mesoscale diffusion and Mo-Fe-C sites formation over monodispersed hollow Fe@MoS2-C sub-micro reactors for boosted OER performance. According to finite element simulation and analysis, the hollow nanostructured MoS2-C host possessed much better mesoscale diffusion properties than its solid and yolk–shell counterparts. Notably, the sulfur vacancies and intercalated carbon in the sub-micro reactor offered a unique microenvironment for Fe anchoring on Mo-Fe-C sites. The stability and activity of the sites were revealed by theoretical calculations. The resultant Fe@MoS2-C presented an OER overpotential of 194 mV, which is much better than those of the Fe-based single-atom catalysts reported to data. Our monodispersed sub-micro reactor combined the advantage of mesoscale diffusion and single-atom sites, and it may have broad prospects for complex electrocatalytic reactions.

scholarly journals Supercritical water oxidation for the destruction of hazardous waste: better than incineration

2015 ◽  
Vol 373 (2057) ◽  
pp. 20150013 ◽  
Author(s):  
Bushra Al-Duri ◽  
Faihan Alsoqyani ◽  
Iain Kings
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Isopropyl Alcohol ◽  
Flow Reactor ◽  
Plug Flow ◽  
Reaction Medium ◽  
Supercritical Water Oxidation ◽  
Split Ratio ◽  
N Removal ◽  
Better Than

Supercritical water oxidation (SCWO) is an advanced process mainly employed for the treatment of hazardous stable wastes, otherwise treatable by incineration. It is based on the unique properties of water above its critical point ( T c =675 K, P c =22.2 MPa), making it a superior reaction medium for the destruction of all organics in the presence of oxygen. This work presents preliminary laboratory scale studies on SCWO of nitrogen (N)-containing hazardous hydrocarbons, with a view to enhancing the process performance, using available reagents and non-complex reactor design. This article investigates the destruction of dimethylformamide (DMF), carried out in a continuous (plug flow) reactor system. SCWO of DMF was enhanced by (i) a split-oxidant system, where stoichiometric oxidant was divided between two inlet ports at various ratios and (ii) the addition of isopropyl alcohol (IPA) as a co-fuel, premixed with the feedstock. Testing a range of temperatures, initial DMF concentrations, oxidant ratios, IPA ratios and oxidant split ratios, selected results were presented in terms of % total organic carbon and % N removal. Reaction kinetics were studied and showed a dramatic decrease in the activation energy upon adding IPA. Split-oxidant-feeding enhancement depended on the split ratio and secondary feed position.

Bimetallic cooperative effect on O–O bond formation: copper polypyridyl complexes as water oxidation catalyst

2018 ◽  
Vol 47 (26) ◽  
pp. 8670-8675 ◽  
Author(s):  
Xiao-Jun Su ◽  
Chu Zheng ◽  
Qin-Qin Hu ◽  
Hao-Yi Du ◽  
Rong-Zhen Liao ◽  
...  
Keyword(s):  
Copper Complex ◽  
Water Oxidation ◽  
Bond Formation ◽  
Catalytic Efficiency ◽  
Cooperative Effect ◽  
Oxidation Catalyst ◽  
Binuclear Copper ◽  
Polypyridyl Complexes ◽  
Binuclear Copper Complex ◽  
Better Than

Two is better than one. The bimetallic cooperation in a binuclear copper complex, compared with the corresponding mononuclear catalyst, can decrease the catalytic overpotential and improve the catalytic efficiency.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Localization of immunolabels by electron microscopy and image averaging

1983 ◽  
Vol 41 ◽  
pp. 282-283
Author(s):  
J. Frank ◽  
P.-Y. Sizaret ◽  
A. Verschoor ◽  
J. Lamy
Keyword(s):  
Electron Microscopy ◽  
Single Particle ◽  
Attachment Site ◽  
Uranyl Acetate ◽  
Limulus Polyphemus ◽  
Resolution Limit ◽  
Electron Microscopic ◽  
Image Averaging ◽  
Top View ◽  
Better Than

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Electron Microscopic Observation of the Longitudinal Organization of Poly (p-Phenylene Terephthalamide) Fibers

1982 ◽  
Vol 40 ◽  
pp. 680-681
Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Microscopic Observation ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Aromatic Polyamides ◽  
Radial Arrangement ◽  
Scanning Electron ◽  
Better Than

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.

A High Angle, Double Tilting Cold Stage for the AEI EM7

1974 ◽  
Vol 32 ◽  
pp. 450-451
Author(s):  
P.R. Swann ◽  
A.E. Lloyd
Keyword(s):  
Habit Plane ◽  
Temperature Control ◽  
Tilt Angle ◽  
Cooling System ◽  
Thermal Drift ◽  
High Angle ◽  
Cold Stage ◽  
High Degree ◽  
Better Than

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.

Thermal Considerations in Lens Regulator Systems

1970 ◽  
Vol 28 ◽  
pp. 358-359
Author(s):  
K.C. Newton
Keyword(s):  
Electron Microscope ◽  
Thermal Effects ◽  
Environmental Control ◽  
Reference Networks ◽  
Better Than

Thermal effects in lens regulator systems have become a major problem with the extension of electron microscope resolution capabilities below 5 Angstrom units. Larger columns with immersion lenses and increased accelerating potentials have made solutions more difficult by increasing the power being handled. Environmental control, component choice, and wiring design provide answers, however. Figure 1 indicates with broken lines where thermal problems develop in regulator systemsExtensive environmental control is required in the sampling and reference networks. In each case, stability better than I ppm/min. is required. Components with thermal coefficients satisfactory for these applications without environmental control are either not available or priced prohibitively.

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