A series of Au/TiO2 samples with gold loadings ranging from 0.11% to 1.26% have been prepared by deposition-precipitation, characterised by means of XRD, S-BET, XRF, TEM, XPS and DR UV-Vis techniques and tested in the gaseous CO oxidation and photocatalytic degradation of phenol in aqueous media. The catalytic performances of the solids on both reactions…
The present article focuses on an interdisciplinary research on cultural heritage concerning the microanalysis of Gothic mural paintings made during the 15th century in Slovenia. The samples were chosen from the churches of Crngrob (1453), Mirna (1463-1465), Mevkuz (1465) and Mate (1467), attributed to two of the most important Gothic painters of that period of time: Master Bolfgang and Master of Mate. The chemical and phase composition of all the mortars, number of their layers and selection of the pigments were of interest. For this purpose, fragments of mural paintings were studied with several instrumental techniques: optical microscopy (OM), SEM-EDX, x-ray powder…
The state of the nickel in a Ni/CeO2 catalyst during hydrogen reduction, steam and dry reforming of methane, have been studied by means of in situ XAS spectroscopy. The catalyst was prepared by a combustion method and, after calcination, very small (about 10 nm) and homogeneous cubic particles of NiO are formed. Once reduced in hydrogen at…
We report here on the degradation of diphenylmercury and monophenylmercury chloride in air-equilibrated aqueous solutions by heterogeneous photocatalysis over alpha-Fe2O3. Photocatalysis proceeded via sequential de-phenylation leaving inorganic mercury. GC-MS analysis of the products revealed that photocatalytic degradation involved hydroxylation of the phenyl rings. Mechanistic features and photocatalytic activity were also studied and are reported upon.
An electron reaching the detector after being backscattered from a solid surface in a reflection electron energy loss spectroscopy (REELS) experiment follows a so-called V-type trajectory if it is reasonable to consider that it has only one large elastic scattering event along its total path length traveled inside the solid. V-type trajectories are explicitly assumed…
The crystal growth kinetics of antimony trisulfide in (GeS2)(0.1)(Sb2S3)(0.9) glass has been studied by microscopy and DSC. The linear crystal growth kinetics has been confirmed in the temperature range 492 <= T <= 515 K (E-G = 405 +/- 7 kJ mol(-1)). The applicability of standard growth models has been assessed. From the crystal growth…
Ar + NO microwave discharges are used for sterilization and the results are compared with additional experiments with Ar, O(2) and N(2)-O(2) plasma mixtures. The NO* species produced in the Ar – NO mixtures remain up to long distances from the source, thus improving the sterilization efficiency of the process. E. coli individuals exposed to…
The tribological behaviour of nanocomposite coatings made of nanocrystalline metal carbides and amorphous carbon (a-C) prepared by PVD/CVD techniques is found to be very dependant on the film deposition technique, synthesis conditions and testing parameters. Focusing in the TiC/amorphous carbon-based nanostructured system, this paper is devoted to an assessment of the factors governing the tribological…
An important improvement of the photocatalytic activity of sol-gel prepared TiO2 has been achieved by sulphate pre-treatment, calcination at high temperature and further platinisation of the samples. The presence of sulphuric acid clearly stabilised TiO2 surface area against sintering, maintaining at the same time anatase phase until higher calcination temperatures than in non-sulphated samples. Platinisation…
