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A novel hybrid nanocomposite formed of carboxylated Nano Graphene Oxide (c-NGO), highly densely decorated by monodisperse citrate-coated Au nanoparticles (c-NGO/Au NPs), is synthesized and thoroughly characterized for photothermal applications. A systematic investigation of the role played by the synthetic parameters on the Au NPs decoration of the c-NGO platform is performed, comprehensively studying spectroscopic and morphological characteristics of the achieved nanostructures, thus elucidating their still not univocally explained synthesis mechanism. Remarkably, the Au NPs coating density of the c-NGO sheets is much higher than state-of-the-art systems with analogous composition prepared with different approaches, along with a higher NPs size dispersion. A novel theoretical approach for estimating the average number of NPs per sheet, combining DLS and TEM results, is developed. The assessment of the c-NGO/Au NPs photothermal activity is performed under continuous wave (CW) laser irradiation, at 532 nm and 800 nm, before and after functionalization with PEG-SH. c-NGO/Au NPs composite behaves as efficient photothermal agent, with a light into heat conversion ability higher than that of the single components. The c-NGO/Au NPs compatibility for photothermal therapy is assessed by in vitro cell viability tests, which show no significant effects of c-NGO/Au NPs, as neat and PEGylated, on cell metabolic activity under the investigated conditions. These results demonstrate the great potential held by the prepared hybrid nanocomposite for photothermal conversion technologies, indicating it as particularly promising platform for photothermal ablation of cancer cells.

Semiconductor/metal nanocomposites based on anatase TiO2 nanoparticles and Au nanorods (TiO2/AuNRs) were prepared by means of a co-precipitation method and subsequently calcinated at increasing temperature (from 250° to 650 °C) obtaining up to 20 g of catalysts. The structure and the morphology of the obtained nanocomposite material were comprehensively characterized by means of electron microscopy (SEM and TEM) and X-ray diffraction techniques. The photocatalytic performance of the TiO2/AuNRs nanocomposites was investigated as a function of the calcination temperature in experiment of degradation of water pollutants under both UV and UV–vis irradiation, Photocatalytic experiments under UV irradiation were performed by monitoring spectrophotometrically the decolouration of a target compound (methylene blue, MB) in aqueous solution. UV–vis light irradiation was, instead, used for testing the photocatalytic removal of an antibiotic molecule, Nalidixic acid, by monitoring the degradation process by HPLC-MS analysis. Interestingly, TiO2/AuNRs calcined at 450 °C was up to 2.5 and 3.2 times faster than TiO2P25 Evonik, that is a commercially available reference material, in the photocatalytic degradation of the Methylene Blue and the Nalidixic Acid, under UV and visible light, respectively. The same nanocomposite material showed a photocatalytic degradation rate for the two target compounds up to 13 times faster than the bare TiO2-based catalysts. The obtained results are explained on the basis of the structure and morphology of the nanocomposites, that could be tuned according to the preparative conditions. The role played by the plasmonic domain in the heterostructured materials, either under UV and UV–vis illumination, is also highlighted and discussed. The overall results indicate that the high photoactivity of TiO2/AuNRs in the visible range can be profitably exploited in photocatalytic applications, thanks also to the scalability of the proposed synthetic route, thus ultimately envisaging potential innovative solution for environmental remediation.

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In this work, the manufacturing and characterization of an optically transparent and UV-Iight photoactive anode, formed of monolayer graphene grown by chemical vapor deposition (CVD) and decorated with a close packed multHayered nanostructured layout of colloidal TiO2 nanocrystals (NCs), are reported. The hybrid material has been prepared by a facile solution-based procedure, which relays on soaking the CVD graphene in a solution of I-pyrene butyric acid (PBA) surface coated TiO2 NCs, achieved upon implementation of a capping exchange process for displacing the pristine organic ligand deriving from the colloidal synthesis. Pyrene undergoes 'It' It stacking interactions, anchoring the NCs to the platform with retention of the NC geometry and composition. The NCs immobilize onto the graphene platform with preservation of its aromatic structure and the resulting hybrid has been found optically transparent in the visible spectral range. (Photo)electrochemical investigation shows that the composite material has a promising sensitivity for selectively detecting dopamine and norepinephrine and, concomitantly, exhibits a (photo)electric activity higher than that of bare graphene. Thus, the achieved hybrid material results interesting for the manufacturing of photo-active components to integrate in photo-renewable sensor elements along with photodetectors and solar cells.

In this work, the manufacturing and characterization of an optically transparent and UV-Iight photoactive anode, formed of monolayer graphene grown by chemical vapor deposition (CVD) and decorated with a close packed multHayered nanostructured layout of colloidal TiOz nanocrystals (NCs), are reported. The hybrid material has been prepared by a facHe solution-based procedure, which relays on soaking the CVD graphene in a solution of I-pyrene butyric acid (PBA) surface coated Ti02 NCs, achieved upon implementation of a capping exchange process for displacing the pristine organic ligand deriving from the colloidal synthesis. Pyrene undergoes 'It- 'It stacking interactions, anchoring the NCs to the platform with retention of the NC geometry and composition. The NCs immobilize onto the graphene platform with preservation of its aromatic structure and the resulting hybrid has been found optically transparent in the visible spectral range. (Photo)electrochemical investigation shows that the composite material has a promising sensitivity for selectively detecting dopamine and norepinephrine and, concomitantly, exhibits a (photo)electric activity higher than that of bare graphene. Thus, the achieved hybrid material results interesting for the manufacturing of photo-active components to integrate in photorenewable sensor elements along with photodetectors and solar cells

Nanocomposite materials have been obtained by dispersing organic capped TiO(2) nanocrystals (NCs) with different shape and surface chemistry in poly(methyl methacrylate) (PMMA) as a host medium. Films of the prepared nanocomposites based on TiO(2) NCs have been fabricated by spin coating and morphologically characterized as a function of the preparative conditions. The organic vapor absorption ability of the PMMA/TiO(2) NC based nanocomposites has been then investigated both for spherical and rod-like NCs, and the chemical nature of the coordinating organic molecules has been also varied. The results of the investigation have demonstrated that NC geometry and surface chemistry can modulate the specific absorption characteristics of the modified PMMA in order to absorb different solvent molecules (i.e. acetone, ethanol, propan-2-ol and water). Such features, due to specific interactions between the potential analyte vapors and the functionalized surface of NCs, can effectively be addressed in a controlled and reproducible way, thus offering original opportunities for designing innovative chemical sensors.