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In this work we propose a new methodology for selective and sensitive pathogen detection based on a 2D layered heterostructured biosensing platform. As a proof of concept, we have chosen SARS-CoV-2 virus because the availability of new methods to detect this virus is still a great deal of interest. The prepared platform is based on the covalent immobilization of molybdenum disulphide functionalized with a diazonium salt (f-MoS2) onto graphene screen-printed electrodes (GPH SPE) by electrografting of the diazonium salt. This chemistry-based method generates an improved heterostructured biosensing platform for aptamer immobilization and aptasensor development. Electrochemical impedance spectroscopy (EIS) is used to obtain the signal response of the device, proving the ability of the sensor platform to detect the virus. SARS-CoV-2 spike RBD recombinant protein (SARS-CoV-2 S1 protein) has been detected and quantified with a low detection limit of 2.10 fg/mL. The selectivity of the developed biosensor has been confirmed after detecting the S1 protein even in presence of other interfering proteins. Moreover, the ability of the device to detect SARS-CoV-2 S1 protein has been also tested in nasopharyngeal swab samples, This work has been financially supported by the Spanish Ministry of Economy and Competitiveness (PID2020-116728RB-I00, PID2020- 116661RB-I00, CTQ2015-71955-REDT (ELECTROBIONET)) and Community of Madrid (TRANSNANOAVANSENS, S2018/NMT-4349, and PhotoArt P2018/NMT-4367). E. Enebral thank the financial support of “Nanotecnología para detección del SARS-CoV-2 y sus variantes. NANOCOV” project. IMDEA Nanociencia receives support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant CEX2020-001039-S). We also thank the Spanish Ministry of Universities for supporting Laura Gutiérrez-Galvez with the Formación del Profesorado Universitario (FPU) grant (FPU19/06309)

[EN] Magnetism and the existence of magnetic order in a material is determined by its dimensionality. In this regard, the recent emergence of magnetic layered van der Waals (vdW) materials provides a wide playground to explore the exotic magnetism arising in the two-dimensional (2D) limit. The magnetism of 2D flakes, especially antiferromagnetic ones, however, cannot be easily probed by conventional magnetometry techniques, being often replaced by indirect methods like Raman spectroscopy. Here, we make use of an alternative approach to provide direct magnetic evidence of few-layer vdW materials, including antiferromagnets. We take advantage of a surfactant-free, liquid-phase exfoliation (LPE) method to obtain thousands of few-layer FePS3 flakes that can be quenched in a solvent and measured in a conventional SQUID magnetometer. We show a direct magnetic evidence of the antiferromagnetic transition in FePS3 few-layer flakes, concomitant with a clear reduction of the Néel temperature with the flake thickness, in contrast with previous Raman reports. The quality of the LPE FePS3 flakes allows the study of electron transport down to cryogenic temperatures. The significant through-flake conductance is sensitive to the antiferromagnetic order transition. Besides, an additional rich spectra of electron transport excitations, including secondary magnetic transitions and potentially magnon-phonon hybrid states, appear at low temperatures. Finally, we show that the LPE is additionally a good starting point for the mass covalent functionalization of 2D magnetic materials with functional molecules. This technique is extensible to any vdW magnetic family., Funds from Ministerio de Ciencia e Innovación in Spain (RTI2018-096075-A-C22, RYC2019-028429-I). E.M.P. thanks the Spanish Ministerio de Ciencia e Innovación (PID2020-116661RB-I00) and Comunidad de Madrid (P2018/NMT-4367). M.G.H. and A.C.-G. acknowledge funds from European Union Horizon 2020 research and innovation program (Graphene Core3-Grant agreement no. 881603 Graphene-based disruptive technologies), EU FLAGACS ERA through the project To2Dox (JTC-2019-009), andComunidad de Madrid through the project CAIRO-CMproject (Y2020/NMT-6661). A.C.-G. also acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 755655, ERC-StG 2017 project 2D-TOPSENSE) and the Ministry of Science and Innovation (Spain) through the project PID2020-115566RB-I00. M.L.R.G. acknowledges support by the Spanish Ministry of Science and Innovation through Research Project PID 2020- 113753RB-100. The National Centre for Electron Microscopy (ELECMI National Singular Scientific Facility) is also acknowledge for provision of access to corrected aberration microscopy facilities. CzechNanoLab Research Infrastructure supported by MEYS CR (LM2018110) is acknowledged.

Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022., The most widespread method for the synthesis of 2D-2D heterostructures is the direct growth of one material on top of the other. Alternatively, one can manually stack flakes of different materials. Both methods are limited to one crystal/device at a time and involve interfacing the 2D materials through van der Waals forces, to the point that all these materials are known as van der Waals heterostructures. Synthetic chemistry is the paradigm of atomic-scale control, yet its toolbox remains unexplored for the construction of 2D-2D heterostructures. Here, we describe how to covalently connect 2H-MoS2 flakes to several single-layer graphene field-effect transistors simultaneously, and show that the final electronic properties of the MoS2-graphene heterostructure are dominated by the molecular interface. We use a bifunctional molecule with two chemically orthogonal anchor points, selective for sulfides and carbon-based materials: On one hand, we exploit the chemistry of maleimide described by our group to functionalize sulfide-based materials under mild conditions. On the other hand, we use a diazonium salt, which is the most common method for the covalent modification graphene. The solvents play a key role to activate a specific part of the molecule for the covalent anchoring. In order to measure the electrical properties of the heterostructure, we have fabricated a number of f-MoS2@graphene field effect transistors (FET) on Si/SiO2 substrates. The electronic properties of the functionalized devices are dominated by the chemical interface, resulting in p-doped devices in which the charge mobility is conserved after reaction, and the degree of doping can be controlled by increasing the degree of functionalization. The results described here show the power of the chemical approach to build functional 2D-2D heterostructures beyond van der Waals. Figure 1: Experimental procedure for the production of MoS2@Graphene covalent heterostructures.

In presented work natural expanded vermiculite was used as a starting material for synthesis of Fe-doped cataly sts. Material was modified with increasing amount of Fe by ion-exchange and precipitation of iron oxide. Composite materials were characterized with respect to their stru cture (X-ray diffraction, Infrared spectra using Diffuse Reflectance), agglomeratio n state of Fe (Ultraviolet-Visible spectra using Diffuse Reflectance) and chemical composition. Activity in H 2 O 2 decomposition as well as in phenol oxidation was studied in liquid phase at atmosphe ric pressure and temperature up to 70 °C. It was shown that doping with Fe increases ca talytic activity. However, excess of iron result ed in formation of undesired side-products.