Monometallic catalysts based on Fe, Ni and Pd, as well as bimetallic catalysts based on Fe-Pd and based on Ni-Pd supported on silica, were synthesized using a sol-gel cogelation process. These catalysts were tested in chlorobenzene hydrodechlorination at low conversion to consider a differential reactor. In all samples, the cogelation method allowed very small metallic nanoparticles of 2-3 nm to be dispersed inside the silica matrix.
View Article and Find Full Text PDFIn this study we report, the synthesis of ZnO and its doping with Transition Metal Oxides -TMO-, such as CrO, MnO, FeO, CoO, NiO, CuO and CuO. Various characterization techniques were employed to investigate the structural properties. The X-ray diffraction (XRD) data and Rietveld refinement confirmed the presence of TMO phases and that the ZnO structure was not affected by the doping with TMO which was corroborated using transmission Electron microscopy (TEM).
View Article and Find Full Text PDFThe plasmonic features of gold nanomaterials provide intriguing optical effects which can find potential applications in various fields. These effects depend strongly on the size and shape of the metal nanostructures. For instance, Au bipyramids (AuBPs) exhibit intense and well-defined plasmon resonance, easily tunable by controlling their aspect ratio, which can act synergistically with chromophores for enhancing their photophysical properties.
View Article and Find Full Text PDFThe use of photosensitizers immobilized on mesoporous materials to produce singlet oxygen (O) has opened a new way to synthetic and environmental applications due to the fast development of flow photochemistry and continuous-flow microreactors. O-based photosensitized processes can be employed for the degradation of organic pollutants in an aqueous medium and the photosensitizer can be covalently attached to the support and separated from the effluent reducing the environmental impact. The aim of the present paper is to evaluate the O generation of Rose Bengal (RB) in homogeneous and heterogeneous systems using in-operando evaluation.
View Article and Find Full Text PDFIn this paper, TiO₂ prepared with an aqueous sol-gel synthesis by peptization process is doped with nitrogen precursor to extend its activity towards the visible region. Three N-precursors are used: urea, ethylenediamine and triethylamine. Different molar N/Ti ratios are tested and the synthesis is adapted for each dopant.
View Article and Find Full Text PDFMetal-enhanced processes arising from the coupling of a dye with metallic nanoparticles (NPs) have been widely reported. However, few studies have simultaneously investigated these mechanisms from the viewpoint of dye fluorescence and photoactivity. Herein, protoporphyrin IX (PpIX) is grafted onto the surface of silver core silica shell NPs in order to investigate the effect of silver (Ag) localized surface plasmon resonance (LSPR) on PpIX fluorescence and PpIX singlet oxygen ( O ) production.
View Article and Find Full Text PDFThis paper investigated the enhancement effect of nanometre-sized metallic (Pd, Ag and Cu) or metallic oxide (FexOy) nanoparticles on fermentative hydrogen production from glucose by a Clostridium butyricum strain. These nanoparticles (NP) of about 2-3 nm were encapsulated in porous silica (SiO2) and were added at very low concentration (10(-6) mol L(-1)) in batch hydrogen production test. The cultures containing iron oxide NP produced 38% more hydrogen with a higher maximum H2 production rate (HPR) of 58% than those without NP or with silica particles only.
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