Fundamentals and advances in magnesium alloy corrosion

Dialkylbiaryl phosphines are a valuable class of ligand for Pd-catalyzed amination reactions and have been applied in a range of contexts. This perspective attempts to aid the reader in the selection of the best choice of reaction conditions and ligand of this class for the most commonly encountered and practically important substrate combinations.

Dialkylbiaryl phosphines in Pd-catalyzed amination: a user's guide

Magnetic ferrospinel MFe 2 O 4 (M = Co, Cu, Mn, and Zn) prepared in a sol–gel process was introduced as catalyst to generate powerful radicals from peroxymonosulfate (PMS) for refractory di-n-butyl phthalate (DBP) degradation in the water. Various catalysts were described and characterized, and the catalytic activities in PMS oxidation system were investigated. Most important of all, the mechanism of different catalysts in the catalytic PMS solution was illustrated. The results showed that the incorporation of CoFe 2 O 4 had the highest catalytic performance in PMS oxidation for DBP degradation. All catalysts presented favorable recycling and stability in the repeated batch experiment. The catalytic process showed a dependence on initial pH, and an uncharged surface of the catalyst was more profitable for sulfate radical generation. H 2 -TPR and CVs analysis indicated that the sequence of the catalyst's reducibility in PMS solution was CoFe 2 O 4  > CuFe 2 O 4  > MnFe 2 O 4  > ZnFe 2 O 4 , which had a close connection with the activity of metal ion in A site of the catalysts. The surface hydroxyl sites played an important role in the catalytic process, and its quantity determined the degradation of DBP. Moreover, the reactive species in PMS/MFe 2 O 4 system were identified as sulfate radical and hydroxyl radical. The promotion of these radical's reaction was due to the fact that a balance action in the process of M 2+ /M 3+ , O 2− /O 2 , occurred, and at the same time, PMS was catalyzed.

Sulfate radicals induced from peroxymonosulfate by magnetic ferrospinel MFe2O4 (M = Co, Cu, Mn, and Zn) as heterogeneous catalysts in the water

The use of light to mediate controlled radical polymerization has emerged as a powerful strategy for rational polymer synthesis and advanced materials fabrication. This review provides a comprehensive survey of photocontrolled, living radical polymerizations (photo-CRPs). From the perspective of mechanism, all known photo-CRPs are divided into either (1) intramolecular photochemical processes or (2) photoredox processes. Within these mechanistic regimes, a large number of methods are summarized and further classified into subcategories based on the specific reagents, catalysts, etc., involved. To provide a clear understanding of each subcategory, reaction mechanisms are discussed. In addition, applications of photo-CRP reported so far, which include surface fabrication, particle preparation, photoresponsive gel design, and continuous flow technology, are summarized. We hope this review will not only provide informative knowledge to researchers in this field but also stimulate new ideas and applications to further advance photocontrolled reactions.

http://pubs.acs.org/doi/pdf/10.1021/acs.chemrev.5b00671

Light-Controlled Radical Polymerization: Mechanisms, Methods, and Applications

This review article summarizes the last few decades of research on nickel hydroxide, an important material in physics and chemistry, that has many applications in engineering including, significantly, batteries. First, the structures of the two known polymorphs, denoted as α-Ni(OH)2 and β-Ni(OH)2, are described. The various types of disorder, which are frequently present in nickel hydroxide materials, are discussed including hydration, stacking fault disorder, mechanical stresses and the incorporation of ionic impurities. Several related materials are discussed, including intercalated α-derivatives and basic nickel salts. Next, a number of methods to prepare, or synthesize, nickel hydroxides are summarized, including chemical precipitation, electrochemical precipitation, sol-gel synthesis, chemical ageing, hydrothermal and solvothermal synthesis, electrochemical oxidation, microwave-assisted synthesis, and sonochemical methods. Finally, the known physical properties of the nickel hydroxides are reviewed, including their magnetic, vibrational, optical, electrical and mechanical properties. The last section in this paper is intended to serve as a summary of both the potentially useful properties of these materials and the methods for the identification and characterization of 'unknown' nickel hydroxide-based samples.

https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.2014.0792

Nickel hydroxides and related materials: a review of their structures, synthesis and properties.

XPS and STM study of the growth and structure of passive films in high temperature water on a nickel-base alloy

XPS comparative study of ceria/zirconia mixed oxides: powders and thin film characterisation

The surface of CexZr1-xO2 compounds has been studied by Fourier transform infrared (FTIR) spectroscopy using adsorbed probe species. Methoxy species, from methanol dissociative adsorption, compensate the coordinative unsaturation of surface cations. From the ν(OC) vibration of methoxy species it was shown that mixed compounds are solid solutions with a surface composition equal to the nominal bulk composition. This result was confirmed by X-ray photoelectron spectroscopy (XPS). However, compared to pure compounds, an increase of exposed Ce4+ cationic sites related to capping oxygen lability was observed for mixed compounds. From the adsorption of CO and pyridine probes it was shown that the Lewis acidities of mixed compounds were intermediate between those of pure ceria and zirconia, which are weak, being slightly higher for zirconia. Using CO2 as a probe for basicity investigation of the surface, it was shown that the various carbonate species observed for mixed compounds were already observed for pure ceria or zirconia with no striking variation of the overall carbonatation. However, from a proposed interpretation of the relative importance of various species, such as monodentate or polydentate carbonates, it was inferred that surface oxygen species are more easily relaxed in ceria-rich mixed compounds than in ceria itself, and that the surface framework of cerium cations is stabilised by zirconium, the effect being the opposite in the case of the surface framework of zirconium ions.

Surface investigation on CexZr1-xO2 compounds

The first steps of H 2 S adsorption have been studied on polycrystalline copper samples, which are more relevant to industrial copper samples than to single-crystal surfaces. The tools for characterization are ultrahigh vacuum spectroscopic methods, such as x-ray photoelectron and ion scattering spectroscopies. The H 2 S adsorption on metallic copper and on the corresponding Cu 2 O and CuO oxides is dissociative and highly dependent on the chemical nature of the exposed surface rather than on the temperature, from room temperature up to 623 K. In our conditions, Cu° sulphidation deals with the top Cu° layer whereas two to three oxide surface monolayers are modified at H 2 S saturation. The results on oxides are interpreted by an oxygen/sulphur replacement mechanism following the dissociative adsorption. Contaminated copper surfaces by phenanthrene or H 2 O treatments are hardly sulphided. As far as surface reactivity is concerned, the adsorbed sulphide species have been shown to be quite strongly bound to the different surface states tested in this work: only oxidative treatments induce desorbing products at 623 K

XPS and ISS studies on the interaction of H2S with polycrystalline Cu, Cu2O and CuO surfaces

The aim of this work is to characterize the oxidation behaviour of different nickel-base alloys exposed to high-temperature and high-pressure water for short oxidation times. The behaviour of Alloy 600 (74% Ni, 16% Cr, 9% Fe), Alloy 690 (60% Ni, 30% Cr, 9% Fe) and Alloy 800 (47% Fe, 32% Ni, 21% Cr) exposed to simulated, pressurised water reactor primary water at 325 °C has been compared. From the combination of chemical and structural data obtained by XPS, nuclear reaction analysis and scanning electron microscopy, the chemical composition and the morphology of the oxide formed on the surfaces have been determined. All alloys present a duplex oxide layer composed of Fe-rich crystals in the external layer and an inner Cr-rich layer that is compact and continuous. The oxide thicknesses were 4-20 nm for Alloy 600 exposed for 0-400 h, 4-40 nm for Alloy 690 exposed for 0-400 h and 4-150 nm for Alloy 800 exposed for 0 to 150 h. The kinetics of oxidation of these samples most probably fit a logarithmic growth equation.

Anouk Galtayries

Papers

XPS and STM study of the growth and structure of passive films in high temperature water on a nickel-base alloy

XPS comparative study of ceria/zirconia mixed oxides: powders and thin film characterisation

Surface investigation on CexZr1-xO2 compounds

XPS and ISS studies on the interaction of H2S with polycrystalline Cu, Cu2O and CuO surfaces

XPS study of oxides formed on nickel‐base alloys in high‐temperature and high‐pressure water