SBA-15-supported copper-chromium mixed oxide nanoparticles (CuCr/SBA-15) were prepared by incipient wetness impregnation followed by mild drying at 25 1C and calcination. The Cu : Cr weight ratios were 1 : 1, 5 : 1, and 10 : 1, at a constant total loading of 5 wt%. Monocomponent SBA-15-supported Cu-oxide (Cu/SBA-15) and Cr-oxide (Cr/SBA-15) were prepared as reference samples. The materials were systematically characterized by XRD at low and high angles, N 2 physisorption, DR UV-vis, FT-IR, and XPS spectroscopies, and TPR. XRD at low angles and N 2 physisorption confirmed the preservation of the mesoporous structure of the SBA-15 support after impregnation and calcination. In the case of monocomponent samples, CuO appeared poorly dispersed, while the Cr species (Cr 2 O 3 , mono-and polychromates) appeared highly dispersed on the surface of the SBA-15 support. The progressive addition of chromium to copper had positive effects on the average crystallite size of CuO, which decreased from B28 nm (Cu/SBA-15) to B3 nm (CuCr/SBA-15; Cu : Cr = 1 : 1), and on reducibility, as well. Metallic active phases were obtained by reducing of the oxide phases under a hydrogen flow at 350 1C. By comparison to the monometallic catalysts, the reduced CuCr/SBA-15 materials were active in the hydrogenation of cinnamaldehyde and chemoselective towards cinnammyl alcohol (450 mol%). The activity can be correlated with the particle size of copper, whereas the high selectivity to unsaturated alcohol can be associated with the presence of dual Cu 0 -Cr n+ sites.

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Chlorophenols were selected for this study because most of them are toxic and difficult to biodegrade. They represent a particular group of priority toxic pollutants listed by the US EPA in the Clean Water Act and by the European Decision 2455/2001/EC. The efficiency of advanced oxidation processes for degradation of chlorophenols has been extensively documented. The catalytic wet hydrogen peroxide oxidation process, involving oxidation with H 2 O 2 and solid catalysts in mild reaction conditions, was found to be very attractive for different pollutants; however, data regarding the degradation of chlorophenols are very scarce. The aims of this paper were: (i) to prepare and characterize a series of iron-exchanged montmorillonites and (ii) to assess their catalytic performances in a Fenton-like process for the oxidation of para-chlorophenol. DR-UV-VIS spectroscopy was tentatively used to elucidate the structure of the iron oxo sites intervening in the reaction. This approach has been used previously for ion-exchanged zeolites and was able to distinguish between isolated Fe(III) species and Fe x O y clusters of different nuclearity. The catalytic tests, performed at room temperature, showed that all iron-containing clays were very active, leading to the complete oxidation of parachlorophenol and a significant reduction of TOC values. 4-chlorocatechol was the major reaction intermediate found in the CWHPO of 4-CP, followed by hydroquinone and traces of benzoquinone, 5-chloro-1,2,4-benzenetriol, 1,2,4-benzenetriol and 3-chloro-muconic acid. The leaching test indicates that the catalytic activity is mainly due to leached iron ions, at least in the second part of the process.

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Copper nanoparticles were successfully synthesized on polyether-functionalized mesoporous silica to investigate the effect of metal loading (10, 25 and 35 wt. % Cu) on their structural and catalytic properties. The oxide forms of these nanocomposite materials were thoroughly characterized by nitrogen physisorption, SAXS, WAXS, TEM, EDXS, and TPR, whereas the metallic forms were analysed by N 2 O chemisorption. The results indicated that the mesostructured SBA-15-like hybrids favoured the generation of highly dispersed supported copper nanoparticles with average sizes in the range of ~2-6 nm, displaying excellent activity in the hydrogenation of cinnamaldehyde. The average particle size was shown to increase with the metal loading. Among the tested catalysts, the highest activity was obtained for the sample having 25 wt. % Cu (total conversion of cinnamaldehyde in 150 min of reaction). All the catalysts exhibited high selectivity towards hydrocinnamaldehyde (> 85 mol %), which did not appear dependent on the copper particle size.