Terephthalate-intercalated nickel-aluminum layered double hydroxides (LDHs) were prepared by a co-precipitation method, with nominal x values in the general formula Ni((1-x))Al(x)(OH)(2)(C(8)H(4)O(4))(x/2) in the range 0.3-0.8. The materials were characterized by X-ray diffraction, X-ray fluorescence spectroscopy, CHN analysis, thermogravimetric analysis, FTIR spectroscopy, EXAFS at the Ni edge and (27)Al NMR spectroscopy. A combination of XRD, XRF and CHN analysis indicated that crystalline LDHs with true x values up to 0.5 were obtained, along with increasing segregation of an aluminum hydroxide phase with increasing aluminum content. The EXAFS analysis indicated an upper limit of ca. 0.6 for the atomic fraction of aluminum at the second nickel coordination sphere. The (27)Al NMR analysis suggested that a phase containing octahedrally co-ordinated Al(3+) is segregated for nominal x values from 0.6 upwards.

The activity of ZnO catalysts is significantly driven by the strength of the basic sites determined by their morphology.

Large selectivity differences were found between supported and unsupported NiMoS catalysts in dibenzothiophene HDS and tetralin HDA.

In CeO2–Al2O3 prepared by the EISA route, Ce4+ can be totally reduced into Ce3+ between 400 and 500 °C with the participation of Al2O3 in the reversible reduction process.

Iron oxide nanoparticles (FeONPs) prepared with plant extracts have been emerging as green and sustainable materials. FeONPs are usually amorphous due to the chelation of the tea polyphenols (TPs) to the iron, and the real nature of the iron compounds is not completely understood. The main goal of this study was to investigate the behavior of the green FeONPs synthesized from an Fe3+ salt and Cammelia sinensis (black tea) extract upon thermal treatment, in order to remove TPs and enable the formation of crystalline materials suitable for a thorough characterization and with the potential for diverse applications. The as-prepared FeONPs were assigned as mixed-valence Fe­(III) oxyhydroxides and Fe­(II)/Fe­(III) ions bound to TPs. A detailed description of the phase transformation upon heating revealed the formation of the rare nano β-Fe2O3 phase at 400 °C, followed by a transformation to α-Fe2O3 as the temperature increased. Above 600 °C, the unprecedented formation of FePO4 and Fe3PO7 was observed, produced from the reaction of Fe2O3 and free phosphate ions present in the black tea leaves, Fe3PO7 being the major phase obtained at 900 °C. Finally, the catalytic potential of the FeONPs to treat the azo dye methyl orange through a heterogeneous Fenton-like system was investigated.

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The present study reports a simple and inexpensive method for improving the textural properties and stability of γ-alumina by adding crushed sugar cane bagasse to the synthesis gel (highly crystalline bayerite was used as an aluminum source). The influence of bagasse was evaluated by varying the biomass/bayerite ratio from 0.05 to 1 wt%. The presence of bagasse increased both surface area and pore volume up to 2.5-fold and 1.5-fold respectively. In addition, mesopores with a mean diameter of 5 nm were observed, which were further increased to 6 nm using hydrolyzed biomass prior to the synthesis. HRTEM measurements highlighted that the presence of biomass raised the formation of pores by enclosure of (111) and (002) lattice planes