The Effect of Reduction on the Adsorptive Behaviour of the TiO/Water Interface

The effect of mild reduction treatment on TiO 2 surfaces has been investigated by the ZPC (zero point of charge) potentiometric technique. Different extents of reduction result in a series of oxides distinguished either by their adsorption characteristics or electrochemical properties. Non-stoichiometric surface oxide formation has been demonstrated by X-ray diffraction and flat-band potential (V fb ) measurements. The generation of surface states with essentially acid–base characteristics has been shown to be a determining factor in the photo-oxidation–photodecomposition of water. A number of hypotheses relating to the nature of the adsorption-determining sites have been advanced

« L’Affaire Tartuffe, or the Garrison Officers Rehearse Molière (version 1992) »

The recent developments in the discovery of nanoelectrolytes and nanoelectrodes for lithium batteries, fuel cells, and supercapacitors are presented. The nanostructured materials are used for advanced energy conversion and storage devices. The advantages of developing nanoelectrode for lithium batteries includes batter accomodation of the strain of lithium insertion/removal, improving life cycle, new reactions not possible with bulk materials, and short path lengths for electronic transport operation. Nanomaterials offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices

Investigation of the electrochemical behaviour in DMFCs of chabazite and clinoptilolite-based composite membranes

Composite membranes based on recast Nafion with the inclusion of chabazite and clinoptilolite as fillers were used to increase the operation temperature of direct methanol fuel cells (DMFCs). Membranes containing different amounts (3 and 6 vol%) of these zeolites were prepared. The electrochemical behaviour of the composite membranes was investigated at different temperatures (from 90 up to 140 ◦C). Similar performances (around 350–370mWcm−2 under oxygen feed, 200–210mWcm−2 under air feed, at 140 ◦C) were recorded for the cells based on the composite membranes with 3 and 6 vol% of zeolite filler. Cell resistance measurements showed an improvement of the water retention properties at high temperature for the composite membranes compared to bare Nafion

Zeolite-based composite membranes for high temperature direct methanol fuel cells

Composite Nafion membranes containing three natural zeolites (Mordenite, Chabazite and Clinoptilolite) were prepared by using a recast procedure for application in high temperature Direct Methanol Fuel Cells (DMFCs). The Nafion-zeolite membranes have shown good properties for high temperature DMFC application, due to their improved water retention characteristics. A maximum power density of 390 mW cm)2 was achieved at 140 °C with the mordenite-based composite membranes in the presence of oxygen feed. The electrochemical behaviour of the composite membranes was interpreted in the light of surface properties and acidic characteristics of the fillers

Electrocatalytic Activity and Durability of Pt-Decorated Non-Covalently Functionalized Graphitic Structures

Carbon graphitic structures that differ in morphology, graphiticity and specific surface area were used as support for platinum for Oxygen Reduction Reaction (ORR) in low temperature fuel cells. Graphitic supports were first non-covalently functionalized with pyrene carboxylic acid (PCA) and, subsequently, platinum nanoparticles were nucleated on the surface following procedures found in previous studies. Non-covalent functionalization has been proven to be advantageous because it allows for a better control of particle size and monodispersity, it prevents particle agglomeration since particles are bonded to the surface, and it does not affect the chemical and physical resistance of the support. Synthesized electrocatalysts were characterized by electrochemical half-cell studies, in order to evaluate the Electrochemically Active Surface Area (ECSA), ORR activity, and durability to potential cycling and corrosion resistance.ChemE/Chemical EngineeringApplied Science