A simple, nonhazardous, efficient and low energy-consuming process is desirable to generate powerful radicals from peroxymonosulfate (PMS) for recalcitrant pollutant removal. In this work, the production of radical species from PMS induced by a magnetic CuFe2O4 spinel was studied. Iopromide, a recalcitrant model pollutant, was used to investigate the efficiency of this process. CuFe2O4 showed higher activity and 30 times lower Cu2+ leaching (1.5 μg L–1 per 100 mg L–1) than a well-crystallized CuO at the same dosage. CuFe2O4 maintained its activity and crystallinity during repeated batch experiments. In comparison, the activity of CuO declined significantly, which was ascribed to the deterioration in its degree of crystallinity. The efficiency of the PMS/CuFe2O4 was highest at neutral pH and decreased at acidic and alkaline pHs. Sulfate radical was the primary radical species responsible for the iopromide degradation. On the basis of the stoichiometry of oxalate degradation in the PMS/CuFe2O4, the radical ...

Production of Sulfate Radical from Peroxymonosulfate Induced by a Magnetically Separable CuFe2O4 Spinel in Water: Efficiency, Stability, and Mechanism

A broad and critical description of the state-of-the-art in water oxidation electrocatalysts for the oxygen-evolving reaction is given. Technologically relevant catalysts for energy production from earth-abundant metals are highlighted.

/pdf/water-oxidation-at-electrodes-modified-with-earth-abundant-2iewzczshd.pdf

Water Oxidation at Electrodes Modified with Earth‐Abundant Transition‐Metal Catalysts

Hybrid materials based on layered double hydroxides (LDHs) exhibit great potential in diverse fields such as health care, polymer composites, environment, catalysis, and energy generation. Indeed, the compositional flexibility and the scalability of LDH structures, their low cost, and their ease of synthesis have made hybrid LDHs extremely attractive for constructing smart and high-performance multifunctional materials. This review provides a comprehensive and critical overview of the current research on multifunctional hybrid LDHs. Organic–inorganic hybrid LDHs, intercalated and surface-immobilized structures, are both specifically addressed. The new trends and strategies for hybrid LDH synthesis are first described, and then the potential of the latest hybrid LDHs, polymer LDH nanocomposites, and LDH bio-nanocomposites are presented. Significant achievements published from ≈2010, including authors' results, which employ hybrid LDH assemblies in materials science, medicine, polymer nanocomposites, cement chemistry, and environmental technologies, are specifically addressed. It is concluded with remarks on present challenges and future prospects.

Tailoring Hybrid Layered Double Hydroxides for the Development of Innovative Applications

Among various energy-storage devices, electrochemical capacitors (ECs) are prominent power provision but show relatively low energy density. One way to increase the energy density of ECs is to move from carbon-based electric double-layer capacitors to pseudocapacitors, which manifest much higher capacitance. However, compared with carbon materials, the pseudocapacitive electrodes suffer from high resistance for electron and/or ion transfer, significantly restricting their capacity, rate capability and cyclability. Rational design of electrode materials offers opportunities to optimize their electrochemical performance, leading to devices with high energy density while maintaining high power density. This paper reviews the different approaches of electrodes striving to advance the energy and power density of ECs.

Pseudocapacitive materials for electrochemical capacitors: from rational synthesis to capacitance optimization

Electrochemical capacitors, also known as supercapacitors, are energy storage devices, characterized by rapid rates of charging and discharging and high power density. In recent years, electrochemical capacitors have attracted significant attention as ‘bridges’ for the power/energy gap between traditional capacitors and batteries/fuel cells. The integrated performance of an electrochemical capacitor is essentially determined by its electrode materials. This is a review of electrode materials for electrochemical capacitors, chiefly concerning transition metal hydroxides. In this work, we focused particularly on recently published reports using cheap metal hydroxides as electrode materials for electrochemical capacitors, based on classification of metal hydroxide by composition and microstructure. Some important experimental data on this issue are indicated and summarized. Furthermore, a brief discussion of future development, challenges, and opportunities in this area is also provided.

Recent development of metal hydroxides as electrode material of electrochemical capacitors

We studied a series of NiAl–CO3 layered double hydroxides (LDHs) of various degrees of crystallinity prepared by a glycine-assisted hydrothermal method. The structures and the microstructures were determined by Rietveld refinement with a spherical harmonic-implemented algorithm using high-resolution synchrotron powder X-ray diffraction (XRD) data. These XRD results combined with transmission electron microscopy (TEM) observations indicate that the broadening of 00l diffraction lines is mainly due to size effects, while both size and strain effects contribute to the anisotropic broadening of the other hkl reflections. The in-plane TEM dimensions of LDH platelets are found larger than the coherent lengths in the 110 direction, indicating a noncoherent coalescence of domains during crystal growth. The DIFFaX program was also used to model structural defects, i.e., CO32–/SO42– interstratification and intergrowth between rhombohedral 3R1 and hexagonal 2H1 polytypes. Furthermore, the distribution of the cations...

A. De Roy

Papers

Correlation among Structure, Microstructure, and Electrochemical Properties of NiAl–CO3 Layered Double Hydroxide Thin Films

Polymerization of Silicates in Layered Double Hydroxides.

New Cu‐Cr Layered Double Hydroxide Compound: Discussion of Pillaring with Intercalated Tetrahedral Anions.

Evolution related to hygrometry of two lamellar double hydroxide pillared structures [CuCrS04] and [ZnAlS04]

Post-synthesis modification of layered double hydroxides