Suchergebnisse

Resumen del trabajo presentado al Internantional Meeting on the Chemistry of Nanotubes: Science and Applications (ChemonTubes), celebrado en Zaragoza del 6 al 9 de abril de 2008. ; Funding from Spanish Ministry of Education and Science (MEC) and European Regional Development Fund (ERDF) under projects NANOPOLICOND (MAT 2006-13167-C02-02) and NANO-TPE (MAT2007-66927- C02-01), as well as from Regional Government of Aragon (DGA) under Consolidated Group Programme (DGAT66 CNN) is gratefully acknowledged. ; Peer reviewed

X-ray scattering (XRS) experiments have been performed on multi-layered graphene oxide (GO) paper. GO can be easily hydrated as water naturally intercalates in the hydro­philic nanostructure. The effect of the intercalated water on the XRS signals is measured during dehydration under thermal treatment in the temperature range 298–473 K as well as during hydration under saturated water vapour pressure. A simple modelling of the XRS signals by taking into account the presence and the type of intercalated water (bound water or physisorbed water) is introduced. It allows an explanation of the variations of intensity and position of XRS reflections observed experimentally. ; EP, SR and PL benefited of a grant from the French Research National Agency under the program Investissements d'Avenir (SEDECO project, ANR-10-LABX-0035: Labex NanoSa-clay). AMB and WKM acknowledge funding from the Spanish Ministry MINECO under projects ENE2013-48816-C5-5-R and ENE2016-79282-C5-1-R with their associated European Regional Development Funds, and from the Government of Aragon under Consolidated Group programme DGA-T66-GCNN and the associated European Social Fund. ; Peer Reviewed

In this work, a novel amperometric biosensor based on gold nanoparticles anchored on reduced graphene oxide (RGO-AuNPs) and L-lactate dehydrogenase (LDH) was developed for the sensing of Llactate. Firstly, the RGO-AuNPs modified screen printed electrodes were tested for NADH detection showing a wide dynamic range and a low detection limit. Next, the biosensor was constructed by incorporating both enzyme and RGO-AuNPs in a sol gel matrix derived from tetrametoxysilane and methyltrimetoxysilane. The enzyme loading, working pH, and coenzyme concentration were optimized. The biosensor linearly responded to L-lactate in the range of 10 μM - 5 mM and showed a good specific sensitivity of 154 μA/mM·cm2 with a detection limit of 0.13 μM. This was accompanied by good reproducibility and operational stability. Tests on artificial serum proved that L-lactate can be determined practically without interferences from commonly interfering compounds such as urate, paracetamol and L-ascorbate. Our LDH/RGO-AuNPs/SPCE based biosensor thus performs as electrochemical device for the detection of L-lactate as a viable early cancer bio-marker. ; This work was supported by Romanian National Authority for Scientific Research, grant PN-IIID- PCE-2011-3-0286 and FP7 Marie Curie PIRSES_GA_2012-318053: SMARTCANCERSENS. Ana M. Benito and Wolfgang K. Maser would like to thank the Spanish Ministry MINECO (Projects MAT2010-15026 and ENE2013-48816-C5-5-R), the Spanish National Research Council CSIC (Project 201080E124), and the regional Government of Aragon and the European Social Fund (Project DGA-ESF T66) for financial support. ; Peer reviewed

5 pages, 3 Figures, Supplementary Data ; In this communication we present a potentiometric aptasensor based on chemically modified graphene (transducer layer of the aptasensor) and aptamers (sensing layer). Graphene oxide (GO) and reduced graphene oxide (RGO) are the basis for the construction of two versions of the aptasensor for the detection of a challenging living organism such as Staphylococcus aureus. In these two versions, DNA aptamers are either covalently (in the GO case) or non-covalently (in the RGO case) attached to the transducer layer. In both cases we are able to selectively detect a single CFU/mL of S. aureus in an assay close to real time, although the noise level associated to the aptasensors made with RGO is lower than the ones made with GO. These new aptasensors, that show a high selectivity, are characterized by the simplicity of the technique and the materials used for their construction while offering ultra-low detection limits in very short time responses in the detection of microorganisms. ; Spanish Ministry of Science and Innovation (MICINN) through project grants CTQ2010-18717, MAT2010-15026 ; Spanish Higher Research Council CSIC under project 201080E124 ; Regional Government of Aragon and the European Social Fund under project DGA-FSE-T66 CNN ; Peer reviewed

Resumen de la comunicación oral presentada en el Congreso ChemOnTubes 2022, celebrado en Donostia-San Sebastián (España) del 24 al 28 de Abril. ; Hydrogen is considered as one of the most suitable alternatives to fossil fuels if produced from water using renewable resources. Particularly, photoelectrochemical (PEC) water splitting is a well-known technology that allows to obtain green hydrogen through a combination of electricity and sunlight. This process requires photoelectrodes composed of a conductive substrate and a photoactive phase. The present work demonstrates that singlewalled carbon nanotubes (SWCNTs) can be processed along with nanocellulose, a biocompatible adjuvant that enables waterborne inks, into conductive films [1]. SWCNT inks were spray-coated over glass substrates in the form of films. Their low electrical resistivity values (Figure 1a) highlight that SWCNT films are valuable alternatives to typically employed opaque substrates in electrochemical devices, such as pyrolytic graphite. Subsequently, a TiO2 layer was deposited onto the SWCNT films, thus rendering the desired photoanodes (Figure 1b). Electrochemical measurements show that the as-prepared photoanodes display a noticeable photocurrent (Figure 1c), being a clear indicative of their water splitting activity. This is an unprecedented feature for this type of electrode configuration. ; Spanish MICINN/AEI: PID2019-104272RB-C51/AEI/10.13039/501100011033; Government of Aragón: Grupos Reconocidos DGA T03_20R.

1 Figure.-- Abstract of the work presented at "Current Trends in Electrochemistry", 41st Meeting of the Electrochemisty Group of the Spanish Royal Society of Chemistry, 1st French‐Spanish Atelier/Workshop on Electrochemistry, 6 - 9 July 2021, Paris (France). ; Photoelectrochemical techniques are accurate for the study of intrinsic electronic properties of a great variety of nanostructured semiconductor materials, such as conductive polymers, carbon nanomaterials (GO, CNTs, CDs) or metal oxide nanoparticles. It is also a highly valuable implement to assess charge and/or energy transfer phenomena between the mentioned semiconductors unveiling their role as charge acceptors/donors, blockers/transporters, sensitizers/conditioners, or even as photoelectroactive materials for themselves, thus allowing the tuning of optoelectronic properties of composite materials, for their future application in fields related to energy and environment, such as water splitting, electronics, solar cells or water remediation. This versatility makes photoelectrochemistry a key tool in the field of nanoscience and nanotechnology. ; MINECO and AEI/FEDER/UE (project ENE2016-79282-C5-1-R), European Union (H2020-MSCAITN- 2014-ETN 642742), Gobierno de Aragón (Grupo Reconocido DGA T03_17R, FEDER/UE). ; Peer reviewed

1 figure.-- Talk delivered at the HeteroNanoCarb-2019 Conference, Advances and applications in carbon related nanomaterials: From pure to doped structures including heteroatom layers, 2019, December 09th -- 13th, Centro de Ciencias de Benasque Pedro Pascual in Benasque (Aragon, Spain). ; Photoelectrochemistry is a valuable technique for the study of intrinsic electronic properties of a great variety of nanostructured semiconductor materials, such as conductive polymers or metal oxide nanoparticles. It is also a highly valuable implement to assess charge and/or energy transfer phenomena between the mentioned semiconductors and carbon nanomaterials (GO, CNTs), unveiling their role as charge acceptors/donors, blockers/transporters, sensitizers/conditioners, or even as photoelectroactive materials for themselves, thus allowing the tuning of optoelectronic properties of composite materials, for their future application in fields related to energy and environment, such as water splitting, solar cells or water remediation. This versatility makes photoelectrochemistry a key tool in the field of carbon nanoscience and nanotechnology. ; MINEICO (project ENE2016-79282-C5-1-R, AEI/FEDER, UE), European Union (H2020-MSCA-ITN-2014-ETN 642742 ), Gobierno de Aragón (Grupo Reconocido DGA T03_17R, FEDER, UE).

We report on the preparation, characterization and photophysical and electrocatalytic properties of carbon dots (CDs)/MoS2 ensembles. Based on electrostatic interactions, ammonium functionalized MoS2, prepared upon reaction of 1,2-dithiolane tertbutyl carbamate with MoS2 followed by acidic deprotection, was coupled with CDs bearing multiple carboxylates on their periphery as derived upon microwave-assisted polycondensation of citric acid and ethylenediamine followed by alkaline treatment. Insights into electronic interactions between the two species within CDs/MoS2 emanated from absorption and photoluminescence titration assays. Efficient fluorescence quenching of CDs by MoS2 was observed and attributed to photoinduced electron/energy transfer as the decay mechanism for the transduction of the singlet excited state of CDs. Finally, the electrocatalytic performance of CDs/MoS2 was assessed towards the hydrogen evolution reaction and found superior as compared to that owed to the individual CDs species. ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 642742 ; Peer reviewed

We report on the growth of non-stoichiometric nanocrystalline hydroxyapatite (nHAp) with a composition similar to natural bone by a wet-chemical in-situ precipitation route on carbon nanotubes (CNTs) with different degrees of oxygen functionalities and on graphene oxide (GO). Both, functionalization degree and morphology of CNTs and GO appear as critical parameters controlling the shape and crystallinity of the self-assembled nHAp nanoparticles in the corresponding composite materials. Crystalline nHAp nanoparticles with rod-like morphology were achieved for moderately oxidized CNTs and for GO. On CNTs these grow along the CNT's axis while on GO they form a compact layer. In both cases enhanced nHAp integration onto the respective carbon support is obtained. In vitro bioactivity of the prepared composites exhibits a fast apatite biomineralization process, induced by the presence of nHAp. Depending on its crystalline size and dispersion degree remineralization of the apatite nanoparticles takes place through the inclusion of PO4 3 and CO32 by ion exchange. Importantly, during the stage of bioactivity the integration degree of nHAp nanoparticles on the carbon nanostructures alters with time, evidencing the potential of GO as valuable bioceramic support material. ; Spanish Ministry MINECO (project MAT201015026 ; Spanish National Research Council CSIC (project 201080E124, and PhD grant JAEPre09-01155) ; Regional Government of Aragon and the European Social Fund (DGA-ESF-T66 Grupo Consolidado) ; EU COST network MP0901 NanoTP ; EU 7th Framework Program (Grant Agreement 312483-ESTEEM2) ; Peer reviewed

Available online June 23, 2012.- El pdf del artículo es la versión post-print ; Composites of thermoplastic polyurethane (TPU) and ultra-thin graphite (UTG) with concentrations ranging from 0.5 wt.% to 3 wt.% were prepared using a solution compounding strategy. Substantial reinforcing effects with increased loadings are achieved. Compared to neat TPU, values for storage modulus and shear viscosity are enhanced by 300% and 150%, respectively, for UTG concentrations of 3 wt.%. Additionally, an enhancement of thermal properties is accomplished. The crystallization temperature and thermal stability increased by 30 C and 10 C, respectively, compared to neat TPU. Furthermore, the use of oxidized UTG (UTGO) with its added functional oxygen groups suggests the presence of chemical interactions between UTG and TPU, which additionally impact on the thermal properties of the corresponding composites. Controlling the oxidation degree, thus offers further possibilities to obtain composites with tailored properties. The presented approach is straightforward, leads to homogeneous TPU-UTG composites with improved materials properties and is especially suitable for commercial UTG materials and further up-scaled production. ; This research was supported by IMPIVA under project (IMIDIP/2010/58), Spanish Ministry of Science and Innovation (MICINN) under project MAT2010-15026, CSIC under project 201080E124, and the Government of Aragon (DGA) and the European Social Fund (ESF) under project DGA-ESF-T66 CNN. M. C. thanks MICINN and ESF for her grant nº BES-2008-003503. Authors thank Merquinsa S.L. (Barcelona, Spain) and AVANZARE S.L. (La Rioja, Spain) for kindly providing polyurethane and ultrathin graphite samples, respectively. ; Peer Reviewed

1 figure.-- Talk delivered at the HeteroNanoCarb-2019 Conference, Advances and applications in carbon related nanomaterials: From pure to doped structures including heteroatom layers, 2019, December 09th -- 13th, Centro de Ciencias de Benasque Pedro Pascual, in Benasque (Aragon, Spain). ; Poly(3-hexylthiophene) (P3HT) is one of the most popular conductive polymers for optoelectronic applications. [1] Their device operation critically depends on the nanocrystalline domain structure, i.e. the aggregate structure acquired by the polymer chains. Most common aggregates' distribution corresponds to H-aggregates, which implies charge transfer across the chains compared to those acquiring a J- aggregate structure with favorable charge transport along the chains. [2] We recently have shown that strong interactions between P3HT and water-dispersible graphene oxide can be obtained upon the formation of P3HT nanoparticles in aqueous dispersions. [3,4] These interactions enable a significant modification of the internal structure of P3HT aggregates towards a structure predominated by J-aggregates. Following this approach, in this work we have synthesized P3HT nanoparticles by the re-precipitation method in the presence of various types of water-soluble carbon nanostructures. Under scrutiny are graphene oxide flakes of different sizes, as well as nanocrystalline cellulose of type I and II. Of all the nanostructures exploited, the rarely investigated nanocyrstalline cellulose of type II, [5] exhibits significantly enhanced synergetic interface interactions with P3HT nanoparticles. This finding not only reveals a great potential towards improved thin film optoelectronic device structures, but even more underlines value of nanocellulose II for the development of green inks of photoactive polymers, ready to be used for printed electronics. ; Funding by EU (Project H2020-ITN 2014 642742), Spanish MINEICO (Project ENE2016-79282-C5-1-R1 (AEI/FEDER, UE), contract BES2017-080020 including FSE, UE, contract IJCI-2016-27789) and Government of Aragon (DGA-T03-17R and FEDER, UE).

6 Figuras.- 1 Suplemento.- Título del pre-print: "Metallic and semiconducting carbon nanotube features observed in a hybrid titanium dioxide electrode".- This is the pre-peer reviewed version of the following article: ChemPhysChem 20: 838-847 (2019), which has been published in final form at DOI:10.1002/cphc.201900066. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. ; The transfer of nanoscale properties from single‐walled carbon nanotubes (SWCNTs) to macroscopic systems is a topic of intense research. In particular, inorganic composites of SWCNTs and metal oxide semiconductors are being investigated for applications in electronics, energy devices, photocatalysis, and electroanalysis. In this work, a commercial SWCNT material is separated into fractions containing different conformations. The liquid fractions show clear variations in their optical absorbance spectra, indicating differences in the metallic/semiconducting character and the diameter of the SWCNTs. Also, changes in the surface chemistry and the electrical resistance are evidenced in SWCNT solid films. The starting SWCNT sample and the fractions as well are used to prepare hybrid electrodes with titanium dioxide (SWCNT/TiO2). Raman spectroscopy reflects the optoelectronic properties of SWCNTs in the SWCNT/TiO2 electrodes, while the electrochemical behavior is studied by cyclic voltammetry. A selective development of charge transfer characteristics and double‐layer behavior is achieved through the suitable choice of SWCNT fractions. ; This work has been funded by the Spanish Ministry of Science and the European Regional Development Fund (ENE 2016‐79282‐C5‐1‐R), the Government of Aragon (T03‐17R), and the European Commission (H2020‐MSCA‐ITN‐2014‐ETN 642742 "Enabling Excellence"). ; Peer reviewed

[EN] Composites of thermoplastic polyurethane (TPU) and ultra-thin graphite (UTG) with concentrations ranging from 0.5 wt.% to 3 wt.% were prepared using a solution compounding strategy. Substantial reinforcing effects with increased loadings are achieved. Compared to neat TPU, values for storage modulus and shear viscosity are enhanced by 300% and 150%, respectively, for UTG concentrations of 3 wt.%. Additionally, an enhancement of thermal properties is accomplished. The crystallization temperature and thermal stability increased by 30 C and 10 C, respectively, compared to neat TPU. Furthermore, the use of oxidized UTG (UTGO) with its added functional oxygen groups suggests the presence of chemical interactions between UTG and TPU, which additionally impact on the thermal properties of the corresponding composites. Controlling the oxidation degree, thus offers further possibilities to obtain composites with tailored properties. The presented approach is straightforward, leads to homogeneous TPU-UTG composites with improved materials properties and is especially suitable for commercial UTG materials and further up-scaled production. ; This research was supported by IMPIVA under Project (IMIDIP/2010/58), Spanish Ministry of Science and Innovation (MICINN) under Project MAT2010-15026, CSIC under Project 201080E124, and the Government of Aragon (DGA) and the European Social Fund (ESF) under Project DGA-ESF-T66 CNN. M.C. thanks MICINN and ESF for her Grant No. BES-2008-003503. Authors thank Merquinsa S.L. (Barcelona, Spain) and Avanzare S.L. (La Rioja, Spain) for kindly providing polyurethane and ultra-thin graphite samples, respectively. ; Menes, O.; Cano, M.; Benedito, A.; Giménez Torres, E.; Castell, P.; Maser, WK.; Benito, AM. (2012). The effect of ultra-thin graphite on the morphology and physical properties of thermoplastic polyurethane elastomer composites. Composites Science and Technology. 72(13):1595-1601. https://doi.org/10.1016/j.compscitech.2012.06.016 ; S ; 1595 ; 1601 ; 72 ; 13

11 figures, 1 table.-- Supplementary information available. ; The development of membranes for nanofiltration applications requires not only selective layers but also suitable supports to control their synthesis as well as to enable efficient and competitive membrane performances. Single-walled carbon nanotube free-standing films (denoted as buckypaper) have been used as supports for the preparation of polyamide (PA) layers by interfacial polymerization (IP) and tested for dead-end nanofiltration for dyes removal (265–1017 Da) from water and organic solvents. The arrangement of the phases during the IP is essential, thus impregnation on the buckypaper support, first with the organic phase and then with the aqueous phase (denoted as inverse IP, iIP) leads to permeances (of up to 28.0 and 31.4 L m−2 h−1 bar−1 for water and methanol, respectively) and rejection values (>96%) that exceed those of the membranes prepared by reversing the impregnation order. Secondly, a double layer PA/zeolitic imidazolate framework (ZIF-8 or ZIF-93) was prepared on the buckypaper (bp). The design of this double layer led to superior membrane performance, in particular for the hydrophilic ZIF-93, as it changes the PA layer properties (increasing both hydrophilicity and surface roughness) providing higher permeances (up to 59.3 and 76.0 L m−2 h−1 bar−1 for water and methanol, respectively) and dye rejections (>98.5%) than the bare PA layer prepared by iIP. This attractive performance of the PA/ZIF-93/bp membrane has been corroborated with experiments in cross-flow nanofiltration and dead-end nanofiltration of aqueous salt solutions, long-term stability nanofiltration and the study the membrane separation performance after a chlorine treatment. The results reported here therefore show the enormous potential of these membrane architectures for a variety of selective separation processes. ; Grants PID2019-104009RB-I00 and PID2019-104272RB-C51 funded by MCIN/AEI/10.13039/501100011033 are gratefully acknowledged (Agencia Estatal de Investigación (AEI) and MCIN (Ministerio de Ciencia e Innovación), Spain). The Aragón Government is also gratefully acknowledged (Grupos reconocidos T43_20R, T03_20R and E25_20R). V. B.-S. thanks the Grant BES-2017-080209 funded by MCIN/AEI/10.13039/501100011033 and by "ESF Investing in your future". ; Peer reviewed

4 figures.-- Supplementary information available. ; Graphene oxide (GO) is widely used as a component in thin film optoelectronic device structures for practical reasons because its electronic and optical properties can be controlled. Progress critically depends on elucidating the nanoscale electronic structure of GO. However, direct experimental access is challenging because of its disordered and nonconductive character. Here, we quantitatively mapped the nanoscopic charge distribution and charge dynamics of an individual GO sheet by using Kelvin probe force microscopy (KPFM). Charge domains are identified, presenting important charge interactions below distances of 20 nm. Charge dynamics with very long relaxation times of at least several hours and a logarithmic decay of the time correlation function are in excellent agreement with Monte Carlo simulations, revealing an universal hopping transport mechanism best described by Efros–Shklovskii's law. ; This research was financed by the Ministerio de Ciencia e Innovación and the Agencia Estatal de Investigación (MICINN/AEI, Spain) and associated Funds of the European Union through the projects "Nano and Meso Scales: Modelling, Structure and Characterization" (PID2019-104272RB-C52/AEI/10.13039/501100011033 and "Photoelectrochemical hydrogen production by optimized graphene-based interfaces" (PID2019-104272RB-C51/AEI/10.13039/501100011033) and the Fundación Séneca through the projects 19907/GERM/15 and 20860/PI/18, as well as the Gobierno de Aragón (Grupo Reconocido DGA-T03_20R). ; E.C. acknowledges funding of his predoctoral contract by Spanish MINEICO and associated European Social Funds (BES2017-080020). ; Peer reviewed