Nanoporous Fe-Based Alloy Prepared by Selective Dissolution: An Effective Fenton Catalyst for Water Remediation.

A fully nanoporous Fe-rich alloy, prepared by selective dissolution of melt-spun Fe43.5Cu56.5 ribbons, exhibits outstanding properties as a heterogeneous Fenton catalyst toward the degradation of methyl orange (MO) in aqueous solution. In addition, the ferromagnetic characteristics of this material enable its wireless manipulation toward specific locations within polluted wastewater. The influence of selective dissolution on the microstructure, sample morphology (surface and cross-section), elemental composition, and magnetic properties of the resulting nanoporous alloy is investigated. The dealloying procedure enhances the saturation magnetization and drastically increases the catalytic performance (i.e., the time required for full degradation of MO from the medium is reduced by a factor of approximately 2 by subjecting the Fe43.5Cu56.5 ribbons to prior dealloying). Remarkably, the effectiveness of this nanoporous material surpasses the results obtained by the homogeneous Fenton reaction using an equivalent concentration of Fe cations leached into the media from the nanoporous alloy. The different factors that promote the high catalytic activity are discussed. The outstanding catalytic activity, together with the simplicity of the synthetic procedure, makes this material very appealing for water remediation using advanced Fenton processes.

Room-temperature synthesis of three-dimensional porous ZnO@CuNi hybrid magnetic layers with photoluminescent and photocatalytic properties.

A facile synthetic approach to prepare porous ZnO@CuNi hybrid films is presented. Initially, magnetic CuNi porous layers (consisting of phase separated CuNi alloys) are successfully grown by electrodeposition at different current densities using H2 bubbles as a dynamic template to generate the porosity. The porous CuNi alloys serve as parent scaffolds to be subsequently filled with a solution containing ZnO nanoparticles previously synthesized by sol-gel. The dispersed nanoparticles are deposited dropwise onto the CuNi frameworks and the solvent is left to evaporate while the nanoparticles impregnate the interior of the pores, rendering ZnO-coated CuNi 3D porous structures. No thermal annealing is required to obtain the porous films. The synthesized hybrid porous layers exhibit an interesting combination of tunable ferromagnetic and photoluminescent properties. In addition, the aqueous photocatalytic activity of the composite is studied under UV-visible light irradiation for the degradation of Rhodamine B. The proposed method represents a fast and inexpensive approach towards the implementation of devices based on metal-semiconductor porous systems, avoiding the use of post-synthesis heat treatment steps which could cause deleterious oxidation of the metallic counterpart, as well as collapse of the porous structure and loss of the ferromagnetic properties.

Facile in situ synthesis of BiOCl nanoplates stacked to highly porous TiO2: a synergistic combination for environmental remediation.

A novel nanocomposite material made of two-dimensional BiOCl nanoplates assembled into highly porous titania has been successfully prepared following a facile sol-gel reaction. Both the TiO2 (anatase) and BiOCl components are crystalline as demonstrated by X-ray diffraction and transmission electron microscopy analyses. TiO2 exhibits a highly porous network and possesses a small crystallite size, whereas BiOCl forms micrometer-sized plates with nanometer thicknesses. Aqueous photocatalytic activity tests with this novel material have been performed on photodegradation of Rhodamine B under ultraviolet-visible light irradiation. Interestingly, the attachment of the BiOCl nanoplates to the TiO2 network significantly enhances the photocatalytic activity of the material compared to that of pure TiO2 due to the formation of BiOCl/TiO2 heterojunctions. Thus, this pertinent synergistic combination of TiO2 and BiOCl proves to be a promising strategy for the large-scale production of a new generation of photocatalysts with excellent properties for the degradation of organic pollutants.

Introducing axial chirality into mesoionic 4,4'-bis(1,2,3-triazole) dicarbenes.

Mesoionic 4,4'-bis(1,2,3-triazole-5,5'-diylidene) Rh(I) complexes having a C2 chiral 4,4'-axis were accessed from 3-alkyltriazolium salts in virtually complete de. Their structure and configurational integrity were assessed by NMR spectroscopy, X-ray crystallography, and chiral HPLC. Computational analysis of the MICs involved in the reaction suggested the formation of a highly stable and unprecedented cation-carbene intermediate species, which could be evidenced experimentally by cyclic voltammetry analysis.