Energy harvested directly from sunlight offers a desirable approach toward fulfilling, with minimal environmental impact, the need for clean energy. Solar energy is a decentralized and inexhaustible natural resource, with the magnitude of the available solar power striking the earth’s surface at any one instant equal to 130 million 500 MW power plants.1 However, several important goals need to be met to fully utilize solar energy for the global energy demand. First, the means for solar energy conversion, storage, and distribution should be environmentally benign, i.e. protecting ecosystems instead of steadily weakening them. The next important goal is to provide a stable, constant energy flux. Due to the daily and seasonal variability in renewable energy sources such as sunlight, energy harvested from the sun needs to be efficiently converted into chemical fuel that can be stored, transported, and used upon demand. The biggest challenge is whether or not these goals can be met in a costeffective way on the terawatt scale.2

http://pubs.acs.org/doi/pdf/10.1021/cr1002326

Solar Water Splitting Cells

Trends in electrocatalytic activity of the oxygen evolution reaction (OER) are investigated on the basis of a large database of HO* and HOO* adsorption energies on oxide surfaces. The theoretical overpotential was calculated by applying standard density functional theory in combination with the computational standard hydrogen electrode (SHE) model. We showed that by the discovery of a universal scaling relation between the adsorption energies of HOO* vs HO*, it is possible to analyze the reaction free energy diagrams of all the oxides in a general way. This gave rise to an activity volcano that was the same for a wide variety of oxide catalyst materials and a universal descriptor for the oxygen evolution activity, which suggests a fundamental limitation on the maximum oxygen evolution activity of planar oxide catalysts.

Universality in Oxygen Evolution Electrocatalysis on Oxide Surfaces

The Atomic Simulation Environment (ASE) is a software package written in the Python programming language with the aim of setting up, steering, and analyzing atomistic simula- tions. In ASE, tasks are fully scripted in Python. The powerful syntax of Python combined with the NumPy array library make it possible to perform very complex simulation tasks. For example, a sequence of calculations may be performed with the use of a simple "for-loop" construction. Calculations of energy, forces, stresses and other quantities are performed through interfaces to many external electronic structure codes or force fields using a uniform interface. On top of this calculator interface, ASE provides modules for performing many standard simulation tasks such as structure optimization, molecular dynamics, handling of constraints and performing nudged elastic band calculations.

/pdf/the-atomic-simulation-environment-a-python-library-for-48jb1pkf0e.pdf

The Atomic Simulation Environment - A Python library for working with atoms

Design and synthesis of materials for efficient electrochemical transformation of water to molecular hydrogen and of hydroxyl ions to oxygen in alkaline environments is of paramount importance in reducing energy losses in water–alkali electrolysers. Here, using 3d-M hydr(oxy)oxides, with distinct stoichiometries and morphologies in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) regions, we establish the overall catalytic activities for these reaction as a function of a more fundamental property, a descriptor, OH–M2+δ bond strength (0 ≤ δ ≤ 1.5). This relationship exhibits trends in reactivity (Mn < Fe < Co < Ni), which is governed by the strength of the OH–M2+δ energetic (Ni < Co < Fe < Mn). These trends are found to be independent of the source of the OH, either the supporting electrolyte (for the OER) or the water dissociation product (for the HER). The successful identification of these electrocatalytic trends provides the foundation for rational design of ‘active sites’ for practical alkaline HER and OER electrocatalysts. Efficient electrochemical transformation of water to molecular hydrogen and of hydroxyl ions to oxygen in alkaline environments is important for reducing energy losses in water–alkali electrolysers. Insight into the activities of hydr(oxy)oxides on platinum catalyst surfaces for hydrogen and oxygen evolution reactions should prove significant for designing practical alkaline electrocatalysts.

Trends in activity for the water electrolyser reactions on 3d M(Ni,Co,Fe,Mn) hydr(oxy)oxide catalysts.

In vivo corrosion of four magnesium alloys and the associated bone response.

A description is given of several principles related to the thermodynamic interpretation of polarization curves: reaction potential, equilibrium potential, affinity, overvoltage, direction in which an electrochemical reaction occurs, and polarization curves of an electrochemical reaction. Applications to some particular cases are given: (a) experimental determination of the thermodynamic equilibrium potential of an irreversible reaction; (6) determination of oxidation reduction catalysts; (c) prediction of conditions of corrosion and passivity of metals and alloys; behavior of mild steel in a bicarbonate medium; behavior of stainless steel in acetate buffer, influence of chlorides; action of chlorides on the corrosion of iron and the remedy for this action; prevention of localized corrosion. © 1954, The Electrochemical Society, Inc. All rights reserved.

/pdf/the-utility-of-thermodynamic-interpretation-of-polarization-4m8winchy4.pdf

The Utility of Thermodynamic Interpretation of Polarization Curves

https://www.technology.matthey.com/wp-content/uploads/pdf/pmr-v3-i2-047-053.pdf

Electrochemical Properties of the Platinum Metals A NEW APPROACH TO STUDIES OF CORROSION RESISTANCE AND CATHODIC PROTECTION

Weitgefaster Uberblick des heutigen Kenntnis- und Erfahrungsstandes, mit ausfuhrlichem Schrifttumsverzeichnis. Die Frage, wie weit die Ergebnisse elektrochemischer Korrosionsprufmethoden Schlusse auf das voraussichtliche Verhalten der Werkstoffe in der Praxis ermoglichen, wird unter verschiedenen Aspekten diskutiert. Nach einer Darstellung der Versuchsmethodik zur Ermittlung der durch Elektrodenpotentiale definierbaren Bestandigkeitsbereiche (Aktivitat, Passivitat, Immunitat) werden verschiedene Anwendungsgebiete erortert: kathodischer und anodischer Korrosionsschutz, Ermittlung der Anfalligkeit fur Lochfras und Spannungskorrosion, elektrokinetische Prufung der Wirksamkeit von Oberflachenbehandlungen, Schutzkriterien fur Korrosionsinhibitoren. Schlieslich werden einige Anwendungen bei der industriellen Routine prufung mitgeteilt.



Comparing the results of electro-chemical corrosion testing methods with the practical performance of the materials



The paper provides an extensive synopsis of present-day knowledge and experience on this subject, with detailed bibliographical notes. The questions as to what extent the results of electrochemical corrosion testing methods permit conclusions concerning the expected performance of the materials in practice is discussed from various aspects. After a description of the test methodology applied to the determination of the stability ranges (activity, passivity, immunity) which can be defined by electrode potentials, the author deals with a number of applications such as: cathodic and anodic corrosion protection, determination of pit corrosion proneness and stress corrosion proneness, electrokinetic tests of the effectiveness of surface treatments, protection criteria for corrosion inhibitors. Finally, some applications in the field of industrial routine testing are discussed.

Marcel Pourbaix

Papers

The Utility of Thermodynamic Interpretation of Polarization Curves

Electrochemical Properties of the Platinum Metals A NEW APPROACH TO STUDIES OF CORROSION RESISTANCE AND CATHODIC PROTECTION

Ein Vergleich zwischen den Ergebnissen der elektrochemischen Korrosionsprüfmethoden und dem Verhalten der Werkstoffe in der Praxis

Kinetic and thermodynamic behaviour inside occluded corrosion cells interpreted by potential/pH diagrams

Atlas of chemical and electrochemical equilibria in the presence of a gaseous phase