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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). ; Graphene oxide (GO) is an elusive but highly fascinating tunable nanostructure. Dispersible in aqueous solutions, it can be easily processed into macroscopic functional materials such as papers, aerogels and thin films for different kinds of applications. Equally, it can be used as versatile platform for the formation of functional hybrid optoelectronic materials. GO-ing on with GO research, we will present our latest findings on the use of GO as unique interface layer. We will demonstrate that GO can be employed in a controllable way to enable or block charge transfer in optoelectronic device structures. Emphasis is given on the unique and highly dynamic charge-transfer interface interactions established with conjugated polymers facilitating improved thin film operation of interest for optoelectronic device structures. ; Funding by EU (Project H2020-ITN 2014 642742), Spanish MINEICO (Project ENE2016-79282-C5-1-R, AEI/FEDER) and Government of Aragon (DGA-T03-17R, FEDER, UE), is gratefully acknowledged.

1 figure.-- Work presented at the 9th Nanodays Workshop on Advanced Materials, Munich (Germany), Sept. 13-15, 2017 ; Intrinsically conducting polymers form the base for the development of plastic electronic devices and hold great promise in optoelectronic applications such as thin film organic field-effect transitors, OLEDS and solar cells. Control of morphology and aggregation states by nanostructuring is essential for improving the device performance. In the last decade, research has focused on liquid phase assembly processes. These afford conjugated polymers in the form of nanoparticles or nanowires, which are dispersible in aqueous dispersions and allow for the fabrication of thin films with well-defined characteristics from environmentally-friendly solutions. Moreover, the liquid phase self-assembly processes provide unique opportunities for the development of novel composite materials with graphene based materials [1, 2]. Here we present our results of our recent work on the development of novel composite materials based of graphene oxide and poly (3-hexylthiophene) (P3HT) [3]. We show that liquid phase assembly processes in the presence of water-soluble graphene oxide sheets lead to the formation P3HT nanoparticles (P3HTNPs) in intimate contact with surrounding sheets of graphene oxide. During the synthesis, graphene oxide acts as a >good> solvent and induces important changes on the internal aggregation structure and the related interchain coupling. At the same time, the charge-transfer properties as a function of GO concentration are modified. Both effects are intimately coupled and lead to the stabilization of of P3HTNPs-GO donor-acceptor nanostructures offering improved charge transport and charge separation characteristics in thin films. ; Funding by EU (Project H2020-ITN 2014 642742), Spanish MINECO (ENE2013-48816-C5-5-R) and Government of Aragon (DGA-ESF-T66), is gratefully acknowledged.

Available online March 22, 2013.- El pdf del artículo es la versión post-print.-Supplementary data associated with this article can be found on pages 21-23. ; We here present an effective strategy to prepare enhanced composites using poly(vinyl alcohol) (PVA) and multiwalled carbon nanotubes (MWCNT). It contains two essential steps. First, the elaboration of homogeneous aqueous MWCNT dispersions and the selection of the most effective dispersing agent. In a sequential dispersion protocol for seven common dispersants, including surfactants and polymers, the dispersion quality and dispersion ability, independent of the intrinsic nature of the dispersing agent were established using zeta-potential and UV-Vis-spectroscopy. Second, the combination of the most effective dispersing agent, namely dodecylbenzenesulfonate (SDBS) with a polymer dispersant of high affinity towards the PVA matrix, namely polyvinylpyrrolidone (PVP). This resulted in homogeneous PVA-MWCNT composites with significantly improved glass transition temperature by up to 12 ºC as a function of the sequential order of dispersant addition. The presented dispersion strategy is straightforward and thus may provide a fast, reliable and general guide for fabricating nanotube composites with improved performance. ; This research was supported by Spanish Ministry of Science and Innovation (MICINN) under project MAT2010-15026, CSIC under project 201080E124, and the Government of Aragon (DGA) under project DGA-T66 CNN. The authors thank Nanocyl S.A. (Sambreville, Belgium) for providing nanotube samples. ; Peer reviewed

6 pages, 2 figures, 2 tables.- First published online 26 April, 2013 ; The synthesis of Pd nanoparticles (Pd-NPs) supported on multiwalled carbon nanotubes (MWCNTs) and the catalytic performance of the resulting material (Pd-NPs/MWCNTs) on hydrogenation reactions are presented. Facile preparation approaches based on the decomposition of Pd precursors in the presence of MWCNTs lead to homogeneous dispersions of supported Pd-NPs with average size of 4 nm and Pd loads about 12%. The catalytic performance of this material was evaluated in hydrogenation reactions of α,β-unsaturated ketones, alkenes, cyclic di-, tri-and tetraenes, aromatic compounds, terpenes and terpenoids, resulting in very high activity offering short reaction times, high conversion rates, notable selectivity, and acceptable recyclabitiliy under mild conditions. ; Financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) and the European Regional Development Fund (ERDF) under projects CTQ2011-22589 and MAT2010-15026, CSIC under project 201080E124, and the Regional Government of Aragon and the European Social Fund (ESF) under projects (DGA-PI086-08 and E-97, and DGA-ESF T66 CNN) is gratefully acknowledged. M. C. thanks MICINN and ESF for her Grant Nº BES- 2008-003503. ; Peer reviewed

The type and distribution of oxygen functional groups in graphene oxide and reduced graphene oxide remain still a subject of great debate. Local analytic techniques are required to access the chemistry of these materials at a nanometric scale. Electron energy loss spectroscopy in a scanning transmission electron microscope can provide the suitable resolution, but GO and RGO are extremely sensitive to electron irradiation. In this work we employ a dedicated experimental set-up to reduce electron illumina- tion below damage limit. GO oxygen maps obtained at a few nanometres scale show separated domains with diferent oxidation levels. The C/O ratio varies from about 4:1 to 1:1, the latter corresponding to a complete functionalization of the graphene flakes. In RGO the residual oxygen concentrates mostly in regions few tens nanometres wide. Specific energy-loss near-edge structures are observed for diferent oxidation levels. By combining these findings with first principles simulations we propose a model for the highly oxidized domains where graphene is fully functionalized by hydroxyl groups forming a 2D-sp3 carbon network analogous to that of graphane. ; AT, AZ and OS acknowledge support from the Agence Nationale de la Recherche (ANR), program of future investment TEMPOS-CHROMATEM (No. ANR-10-EQPX-50). The work has also received funding from the European Union in Seventh Framework Programme (No. FP7/2007 -2013) under Grant Agreement No. n312483 (ESTEEM2). AMB and WKM are grateful for Financial support from the Spanish Ministry MINECO and the European Regional development Fund (project ENE2013-48816-C5-5-R) and from the Regional Government of Aragon and the European Social Fund (DGA-ESF-T66 Grupo Consolidado). The authors are grateful to P. Launois, S. Rouziere and C.P. Ewels for useful discussion. ; 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). ; For the last fifteen years, graphene oxide (GO) has become a material of great importance within the subject of chemically modified graphene (CDG) for its vast potential applications. However, both the chemical structure of Graphene oxide and the diverse processes taking place in thermal reduction of GO into reduced graphene oxide (RGO) are still not completely clear despite the sizable amount of studies concerning this issue. TEM and EELS, using a sample holder capable of heating samples up to 1200ºC within the TEM, is a unique and extensive technique for the analysis of the reduction of GO. Using this technique, we can measure, simultaneously and in situ, four main properties essential to this analysis at several intermediate temperatures and under high vacuum: the oxidation rate, its thickness, its mass density and its sp2-sp3 bond ratio. This study presents an analysis of GO by studying all of the aforementioned properties in two different studies: a first one heating up to 300ºC to better understand the physisorbed and chemisorbed water desorption, and a second one up to 1200ºC focused on the desorption of various oxygen functional groups; as well as the graphitisation of GO. Our results will be compared with previous studies on the matter. ; This work was supported by the Spanish MINECO (MAT2016-79776-P, AEI/FEDER, EU), and European Union H2020 programs Marie Sklodowska-Curie Enabling Excellence (642742), ESTEEM3 (823717), Flag-ERA GATES (JTC - PCI2018-093137) and Graphene Flagship (785219).

1 Esquema.- 4 Figuras ; The performance of organic thin film optoelectronic devices strongly relies on the nanoscale aggregate structure of the employed conjugated polymer. Their impact on electronic interface interactions with adjacent layers of graphene, widely reported to improve the device characteristics, yet remains an open issue, which needs to be addressed by an appropriate benchmark system. Here, we prepared discrete ensembles of poly(3-hexylthiophene) nanoparticles and graphene oxide sheets (P3HTNPs–GO) with well defined aggregate structures of either J- or H- type and imaged their photogenerated charge transfer dynamics across their interface by Kelvin probe force microscopy (KPFM). A distinctive inversion of the sign of the surface potential and surface photovoltage (SPV) demonstrates that J-aggregates are decisive for establishing charge transfer interactions with GO. These enable efficient injection of photogenerated holes from P3HTNPs into GO sheets over a range of tens of nanometers, causing a slow SPV relaxation dynamics, and define their operation as efficient hole-transport layer (HTL). Conversely, H-type aggregates do not facilitate specific interactions and entrust GO sheets the role of charge-blocking layers (CBL). The direct effect of P3HT's aggregate structure on GO's functional operation as HTL or CBL thus establishes clear criteria towards the rational design of improved organic optoelectronic devices. ; This work has received funding from the Spanish MINEICO (project grants ENE 2016-79282-C5-1-R and ENE 2016-79282-C5-4-R) and associated EU Regional Development Funds. A.M.B., E.I., and W.K.M. acknowledge funding from European Union's Horizon 2020 research and innovation programme under the Marie Skłodowksa-Curie grant agreement no. 642742. They also acknowledge the Gobierno de Aragón (Grupo Reconocido DGA T03_17R) and associated EU Regional Development Funds. We also acknowledge institutional support from the Unit of Information Resources for Research at the "Consejo Superior de Investigaciones Científicas" (CSIC) for the article-processing charges contribution. ; Peer reviewed

2 Esquemas.- 5 Figuras ; A facile strategy for the controllable growth of CdS nanoparticles at the periphery of MoS 2 en route the preparation of electron donor‐acceptor nanoensembles is developed. Precisely, the carboxylic group of α‐lipoic acid, as addend of the modified MoS 2 obtained upon 1,2‐dithiolane functionalization, was employed as anchor site for the in‐situ preparation and immobilization of the CdS nanoparticles in an one‐pot two‐step process. The newly prepared MoS 2 /CdS hybrid material was characterized by complementary spectroscopic, thermal and microscopy imaging means. Absorption spectroscopy was employed to register the formation of MoS 2 /CdS, by observing a broad shoulder centered at 420 nm due to CdS nanoparticles, while the excitonic bands of MoS 2 were also evident. Moreover, based on the efficient quenching of the characteristic fluorescence emission of CdS at 725 nm by the presence of MoS 2 , strong electronic interactions at the excited state between the two species within the ensemble were identified. Photoelectrochemical assays of MoS 2 /CdS thin‐film electrodes revealed a prompt, steady and reproducible anodic photoresponse during repeated on‐off cycles of illumination. A significant zero‐current photopotential of ‐540 mV and an anodic photocurrent of 1 μA were observed, underlining improved charge‐separation and electron transport from CdS to MoS 2 . The superior performance of the charge‐transfer processes in MoS 2 /CdS is of direct interest for the fabrication of photoelectrochemical and optoelectronic devices. ; 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. Support of this work by the project "Advanced Materials and Devices" (MIS 5002409) which is implemented under the "Action for the Strategic Development on the Research and Technological Sector", which Submitted_Manuscript is implemented under the "Reinforcement of the Research and Innovation Infrastructures", funded by the Operational Program "Competitiveness, Entrepreneurship and Innovation" (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund) is also acknowledged. A.M.B. and W.K.M. acknowledge Spanish MINEICO (project grant ENE2016-79282-C5-1-R, AEI/FEDER, UE) and the Gobierno de Aragón (Grupo Reconocido DGA T03_17R, FEDER, UE). ; Peer reviewed

2 figures.-- Work presented at the HeteroNanoCarb Conference 2017, 11th-15th December, Benasque (Spain). ; It is of fundamental and practical significance to translate the novel physical and chemical properties of individual graphene nanosheets into the macroscale by the assembly of graphene building blocks into macroscopic architectures with control over the porous structure and functionalities. 3D graphene aerogels have some interesting properties such as high specific surface area, open porous network for ion transport, supra-flexibility, tough mechanical strength and conductive framework which lend them high potential for wide application fields such as supercapacitors, oil-water separations, sorbents, chemical reactor platforms and solar cells.[1-2] One way to prepare 3D aerogels is starting from GO sols and its gelation under hydrothermal conditions [2]. The functional groups of GO nanosheets are removed by reduction resulting in a decrease of hydrophilicity and loss of surface charges, which leads to the crosslinking of RGO nanosheets and ultimate phase separation. Herein, we have varied the hydrothermal synthesis conditions (pH, time, and freezing method) to achieve a control over the pore orientation and size of graphene aerogels. The mechanical properties of the aerogels varied from more rigid to flexible materials. In addition, we have been able to synthetize graphene aerogels with aligned channels resembling honeycomb structures (Figure 1). As a proof of concept, the materials have been tested as hydrophobic absorbents of organic compound and as support for nanodiamonds (Figure 2). The nanodiamonds supported on graphene aerogels have been tested for the selective dehydrogenation of propane providing an excellent performance. ; The financial support from Spanish Ministry MINECO and the European Regional Development Fund (project ENE2016-79282-C5-1-R) and Government of Aragon (Consolidated Group DGAT66).

Gold nanoparticles (AuNPs) with sizes between 3 and 10 nm were firmly supported on pristine multi-walled carbon nanotubes (MWCNT) in high yields by a facile linker-free deposition route using aqueous suspensions of pre-reduced gold precursors. For the first time, the resulting AuNP-MWCNT hybrid material was employed as catalyst for the hydrogenation of a series of substituted nitroarenes under mild reaction conditions. High catalytic activity with turnover frequencies (TOF) values up to 1200 h-1 were achieved accompanied by a remarkable chemoselectivity. Recyclability tests did neither reveal leaching nor changes in size or oxidation states of the AuNPs. The concomitant presence of Au0 and AuI accounts for both the superior catalytic performance and the high stability of the hybrid material. Preferential orientation of nitroarenes on the MWCNT surface due to π-π interactions coupled with coulombic contact of the nitro group to the AuNPs most likely explains the high chemoselectivity of the hybrid material, and further underlines the valuable role of MWCNTs for catalytic reactions. ; Financial support from Spanish MINECO and the European Regional Development Fund (projects MAT2010-15026, ENE2013-48816-C5-5-R and CTQ2011-22589), Spanish National Research Council CSIC (project 201080E124), and Regional Government of Aragon and the European Social Fund DGA-ESF (T66 Grupo Consolidado, E-97, and E-26) is gratefully acknowledged. ; Peer reviewed

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.