Electrochemical durability of magnetite and birnessite modified electrodes with potential application in water splitting

Graphite electrodes were modified with compositions containing either Fe3O4 or δ-MnO2, and their electrochemical durability was investigated using the cyclic voltammetry method. Experimental results indicate that the most stable electrode is the one modified with the composition containing magnetite and Vulcan carbon, when exposed to electrochemical potentials in the anodic domain. Given this result and the potential values at which oxygen is evolved on the electrode, it has the prospect to find application in the water splitting domain

Developing new ecological material with applications in construction industry and pollution reduction

The photocatalytic activity of TiO2 incorporated foam glass obtained from glass waste from household activities with CaCO3 waste from the marble industry samples was studied by evaluating their ability to degrade organic pollutants in aqueous solutions under the action of simulated solar radiation and using UV-VIS spectroscopy as a simple method to monitor dye concentrations over time. Organic dye has been selected as the reference substance for degradation experiments because the dyes are stable at high temperatures and light and are reported as a major source of pollution, especially for the aquatic environment generated by effluents, mostly in textile industry. Given the characteristics of glass foam combined with current requirements in environmental protection to develop smart materials to combat climate change caused by environmental pollution, this study aimed to expand the application potential of cellular glass by functionalizing it with a material with properties photocatalytic in order to degrade various pollutants in the atmosphere

Substitution effect on the physico-chemical properties in crednerite CuMnO2 type materials

Recently, the ABO2 delafossite-type class of materials, B being a transition element, has attracted a lot of interest. First of all in the field of transparent conducting oxides, thin films of CuAlO2 show the unusual combination of high transparency and rather high p-type semi-conductivity [1]. On the other hand, in the field of the exotic magnetic and structural properties, a good example is the CuFeO2 delafossite, a triangular lattice antiferromagnet which has been extensively studied over the last years for its multiferroïcity [2,3]. The ABO2 delafossite structure, where A=Cu and Ag, and B a transition element, belongs to the R-3m space group and is characterised by O-Cu-O dumbells linking layers of edge sharing BO6 octahedra. However, in this class of materials,crednerite CuMnO2occupies a unique placedue to the Jahn-Teller (JT) distortion of the Mn3+ (t2g 3 eg) which leads to a monoclinic structure (C2/m space group at room temperature) and to a different topology of the magnetic triangular lattice and out-of-plane stacking sequence compared to delafossite structure. In this work, we investigated the physico-chemical properties of CuMn1-XBXO2 (B=Al, Mg; x=0 - 0.08) type materials by X-Ray diffraction, SEM-EDAX, thermal analysis, UV-VIS and infrared spectroscopy. The effect of the substitution on the lattice parameter in CuMnO2is significant in order to understand the correlation between the structure and the properties in this compound.The crednerite nanoparticles were synthesized at low temperature by hydrothermal method in teflonlined steel autoclave

Influence of precursors on structure and magnetic properties of CuFe2O4 obtained by coprecipitation

Nanoparticles of copper ferrites were obtained by co-precipitation method using two precursors Cu(CH3COO)2 and Cu(OH)2 with FeS04-7H20. In this paper, we try to demonstrate the influence of precursors on structure and magnetic properties of CuFe20 4 obtained by coprecipitation allow the preparation of high reactive ferrite nanoparticles whose composition, microstructure, size and properties can be rigorously controlled in order to obtain the special requirements of various advanced applications

Photodegradation of rhodamine B by WO3/glass foam visible-light third generation photocatalyst

This work focused on the evaluation of the photocatalytic activity of the glass foam, a chemically and physical stable support, coated with WO3–visible-light photoactive compound for degradation of rhodamine B. In this way, the removal of the rhodamine B in aqueous solution by WO3/glass foam was compared with the removal of rhodamine B by uncoated glass foam during the experimental stages of the photocatalytic tests: adsorption and visible-light irradiation. The uncoated sample presented no photocatalytic activity, whereas WO3/glass foam removed approximately 33% of rhodamine B from aqueous solution. Physical and chemical characterization of the photocatalyst was carried out by 3D scanning microscopy and energy dispersive X-ray spectroscopy (EDAX) coupled with scanning electrone microscopy (SEM)

Effect of synthesis method on the structure and properties of perovskite NaNbO3 type nanomaterials

Ferroelectric nanostructures have attracted much attention recently due to the ongoing demand for miniaturization of devices and discover new phenomena. One of the materials studied intensively in recent years is potassium niobates with perovskite structure is a promising material for electro-optic, nonlinear optical, and photorefractive applications such as frequency doubling, wave guiding, and holographic storage. The structure and morphology of NaNbO3 perovskites are studied in the context of their possible use for sensors application. Materials are prepared by hydrothermal, sol-gel and ultrasonic method using different thermal treatments. Powders obtained were characterized by X-Ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR)

Structural and optical properties of layered ammonium-iron (II) phosphate monohydrate

Ammonium-iron phosphates phases have recently attracted more interest due to their promising applications as fertilizer [1] or as promising anode material for lithium-ion battery application [2], for example. In this context, NH4FePO4·H2O materials are obtained from FeCl2, Fe2O3 and NH4H2PO4 as starting reagents and NH4OH solution by one step hydrothermal method. The factors that affect the formation processes and the product morphologies: the pH and reaction time have been analysed. The as-synthesized compounds have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transform infrared (FT-IR) spectroscopy. The optical properties of NH4FePO4·H2O were for the first time studied in this research work: the material displays ptype conductivity behaviour and the value for direct optical band gap EG is estimated to be approximately ~3.6 eV. The results from this paper suggests that these phosphate materials could be suitable candidates for several applications as for example in photovoltaic technology