Carboxylic functionalization (-COOH groups) of carbon nanotubes is known to improve their dispersion properties and increase the electrical conductivity of carbon-nanotubepolymer nanocomposites. We have studied experimentally the effects of this type of functionalization on the thermal conductivity of the nanocomposites. It was found that while even small quantities of carbon nanotubes (~1 wt%) can increase the electrical conductivity, a larger loading fraction (~3 wt%) is required to enhance the thermal conductivity of nanocomposites. Functionalized multi-wall carbon nanotubes performed the best as filler material leading to a simultaneous improvement of the electrical and thermal properties of the composites. Functionalization of the single-wall carbon nanotubes reduced the thermal conductivity enhancement. The observed trends were explained by the fact that while surface functionalization increases the coupling between carbon nanotube and polymer matrix it also leads to formation of defects, which impede the acoustic phonon transport in the single wall carbon nanotubes. The obtained results are important for applications of carbon nanotubes and graphene flakes as fillers for improving thermal, electrical and mechanical properties of composites.

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Herein we report a novel, easy, fast and reliable microwave-assisted synthesis procedure for the preparation of colloidal zinc oxide nanocrystals (ZnO NCs) optimized for biological applications. ZnO NCs are also prepared by a conventional solvo-thermal approach and the properties of the two families of NCs are compared and discussed. All of the NCs are fully characterized in terms of morphological analysis, crystalline structure, chemical composition and optical properties, both as pristine nanomaterials or after amino-propyl group functionalization. Compared to the conventional approach, the novel microwave-derived ZnO NCs demonstrate outstanding colloidal stability in ethanol and water with long shelf-life. Furthermore, together with their more uniform size, shape and chemical surface properties, this long-term colloidal stability also contributes to the highly reproducible data in terms of biocompatibility. Actually, a significantly different biological behavior of the microwave-synthesized ZnO NCs is reported with respect to NCs prepared by the conventional synthesis procedure. In particular, consistent cytotoxicity and highly reproducible cell uptake toward KB cancer cells are measured with the use of microwave-synthesized ZnO NCs, in contrast to the non-reproducible and scattered data obtained with the conventionally-synthesized ones. Thus, we demonstrate how the synthetic route and, as a consequence, the control over all the nanomaterial properties are prominent points to be considered when dealing with the biological world for the achievement of reproducible and reliable results, and how the use of commercially-available and under-characterized nanomaterials should be discouraged in this view.

A hybrid aerogel, composed of MoS sheets of 1T (distorted octahedral) and 2H (trigonal prismatic) phases, finely mixed with few layers of reduced graphene oxide (rGO) and obtained by means of a facile environment-friendly hydrothermal cosynthesis, is proposed as electrode material for supercapacitors. By electrochemical characterizations in three- and two-electrode configurations and symmetric planar devices, unique results have been obtained, with specific capacitance values up to 416 F g and a highly stable capacitance behavior over 50000 charge-discharge cycles. The in-depth morphological and structural characterizations through field emission scanning electron microscopy, Raman, X-ray photoelectron spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller, and transmission electron microscopy analysis provides the proofs of the unique assembly of such 3D structured matrix. The unpacked MoS structure exhibits an excellent distribution of 1T and 2H phase sheets that are highly exposed to interaction with the electrolyte, and so available for surface/near-surface redox reactions, notwithstanding the quite low overall content of MoS embedded in the reduced graphene oxide (rGO) matrix. A comparison with other "more conventional" hybrid rGO-MoX electrochemically active materials, synthesized in the same conditions, is provided to support the outstanding behavior of the cosynthesized rGO-MoS.

oxidation methods. In particular, a zinc nanobranched structure is deposited by radio-frequency magnetron sputtering on conductive substrates. Then impregnation of the samples in an antimony acetate solution is performed at different times (2 and 4 h) at room temperature. It has to be noted that longer times produce however an appreciable and even complete dissolution of the zinc material in the Sb acetate solution (at 8 and 16 h, respectively), whereas very short impregnation times (30 min) did not result in a signifi cant doping. Therefore, it resulted that a reasonable impregnation time for inducing a satisfying doping level, without altering the morphological properties of the investigated materials, lies in the range of 2-4 h. The impregnation is then followed by a thermal oxidation at 380 °C, having the dual function to oxidize Zn to ZnO and successfully promote the insertion of Sb in the wurtzite structure, leading to doped ZnO at different ratios depending on the impregnation time. This doping results in a p-type conductive structure and we show that ZnO:Sb nanobranched fi lms can be successfully used as piezoelectric nanogenerators, while the presence of ferro electricity, together with a nonzero spontaneous polarization, is found to give rise to the ferroelectric-photovoltaic effect, [ 11 ] which is here reported for the fi rst time for a ZnObased nanomaterial.The highly nanoporous morphology of the starting Zn layer is shown in Figure S1 (Supporting Information). We take advantage of such a high porous volume and exposed surface area to succeed in the optimal impregnation of the Zn materials with the Sb-precursor solution. Figure 1 a shows the surface morphology of pristine ZnO sample, after calcination of Zn grown on a fl uorine-doped tin oxide (FTO)/glass substrate, and considered the reference sample of this work. The surface is mainly formed by elongated and branched nanostructures, giving rise to a nanoporous network (surface area 14 m 2 g −1 , pore volume 0.095 cm 3 g −1 ). [ 7b ] The presence of a similar highly porous and nanobranched morphology (with a pore volume variation of about ±5% with respect to pristine ZnO fi lm) is also visible in the ZnO:Sb fi lms (Figure 1 b,c) and it is found to be independent from the impregnation time and not signifi cantly altered by doping and thermal processes. Further insight into the morphology of the nanoporous fi lms is given by high-resolution transmission electron microscopy (HRTEM) images (from Figure 1 d-f), showing that the nanobranches are actually constituted by grains smaller than 50 nm for both the pristine and the impregnated samples. Moreover, it can be inferred from HRTEM and fast Fourier transform (FFT) image processing that the grains are single crystals with hexagonal Wurtzite ZnO nanomaterials are widely investigated thanks to the copresence of several unique physical properties like their semiconducting and piezoelectric behaviors. Among all the different morphologies, high-surface area nanostructures are of great interest, such as ZnO n...

Sn-decorated Cu (Cu-Sn) electrodes were proposed as an alternative to Ag-and Au-based electrocatalysts for the selective reduction of CO 2 to CO. Here we demonstrate that selectivity does not only depend on catalyst surface composition, but is strongly affected by the electrode morphology. At current densities above 10 mA•cm -2 , we find that morphology can control the CO 2 reduction pathways to CO and other products, including the competing H 2 evolution, on the Cu-Sn surface. An electrode design with dendritic morphological features yields the highest CO partial current density of 11.5 mA•cm -2 at -1.1 V vs. RHE, avoiding the significant loss of CO selectivity observed for an electrode with less sharp, rounder morphological features. Efficient CO 2 mass transport to the catalyst surface and a high local CO 2 concentration, promoted by the dendritic structure, stabilize the Cu-SnO overlayer, suppress the competing H 2 evolution reaction, and maintain CO selectivity above 85% over a wide potential range.

An alkyne monomer, bis(propargyl) fumarate, is synthesized and mixed to a thiol monomer to produce DLP-3D printable formulations. Using off-stoichiometric formulations it is possible to print functionalizable objects.

We report on an easy, fast, eco-friendly, and reliable method for the synthesis of reduced graphene oxide/SnO2 nanocomposite as cathode material for application in microbial fuel cells (MFCs). The material was prepared starting from graphene oxide that has been reduced to graphene during the hydrothermal synthesis of the nanocomposite, carried out in a microwave system. Structural and morphological characterizations evidenced the formation of nanocomposite sheets, with SnO2 crystals of few nanometers integrated in the graphene matrix. Physico-chemical analysis revealed the formation of SnO2 nanoparticles, as well as the functionalization of the graphene by the presence of nitrogen atoms. Electrochemical characterizations put in evidence the ability of such composite to exploit a cocatalysis mechanism for the oxygen reduction reaction, provided by the presence of both SnO2 and nitrogen. In addition, the novel composite catalyst was successfully employed as cathode in seawater-based MFCs, giving electrical performances comparable to those of reference devices employing Pt as catalyst.