Philippe Trens

Electrochemically oxidised graphite.: Characterisation and some ion exchange properties

An evaluation of some of the properties of electrochemically oxidised graphite has been carried out. These studies include textural characterisation, magic angle spinning NMR, ESR and ion exchange properties. A study of the surface morphology has also been carried out using high-resolution transmission electron microscopy and identification of surface groups confirmed by FTIR spectroscopy. The electrochemical method of preparation is shown to confer, to the porous graphite oxide obtained, different surface chemical groups that can be used for ion exchange purposes. ESR shows that Cu(II) is coordinated to the oxidised graphite.

Synthesis of hexagonally packed porous titanium oxo-phosphate

Abstract The synthesis of a hexagonally packed porous titanium oxo-phosphate from titanium isopropoxide, sulfuric acid and alkyltrimethylammonium bromide is reported. XRD and TEM have been used to characterize the mesostructure that forms at ambient temperature as well as the calcined material. The effect of the alkyl chain length of the surfactant has also been studied. The N2-sorption isotherms of the samples calcined at 350°C are characteristic of super-microporous materials. The pore diameters and the surface areas of the materials, evaluated from the N2-sorption isotherms and unit cell parameters, indicate pore diameters of about 2–3 nm and surface areas around 350 m2/g.

Formation of mesoporous, zirconium(IV) oxides of controlled surface areas

Control of the surface areas of the calcined zirconium(iv) oxides arises from the extent of equilibration permitted between the hydrolysed zirconyl oxychloride and the surfactant prior to calcination. The properties of the zirconia–surfactant materials, which are formed by a scaffolding and controlled drying mechanism, and the subsequent oxides obtained on calcination depend more on the times allowed for equilibration than on the ratios of zirconia:surfactant. During the equilibration overca. 24 hr between the hydrolysing zirconium oxychloride and CTAB, the small, unstable zirconium oxide particles mix intimately with the surfactant. These particles recrystallise (and loosely aggregate) on calcination to give tetragonal zirconias of intermediate surface areas