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The apparent viscosity of concentrated clay dispersions is a key control parameter in the ceramic industry, particularly in the manufacture of sanitaryware. Slips, the final industrial dispersions, are complex in their rheological behavior, featuring non-Newtonian flow and thixotropy. In this work, a resonance vibrating-rod viscometer (VRV) was utilized to evaluate the viscosity evolution over time, showing advantages over a classical rotational viscometer. Notably, while both viscometers were sensitive to small quantities of a deflocculant, the VRV effectively described the typical increase in the viscosity of clay dispersions at rest (thixotropy), the experimental data being properly fitted by a phenomenological model. As a relevant technical aspect, the superior suitability of the VRV for in-line process control was highlighted in the continuous monitoring of stirred clay dispersions and slip casting in plaster moulds. Additionally, a fitting model was developed to elucidate viscosity evolution during the casting process. In summary, this study underscores the versatility of the VRV as a control instrument in the sanitaryware industry.

Nanoparticles of poly(3-hexylthiophene), P3HT(NP), uniquely enable the preparation of stable dispersions in environmentally-friendly media and thus offer a sustainable liquid phase fabrication of electrochromic device structures. In this work, we assess the electrochromic performance of P3HT(NP) films spray-coated from either tetrahydrofuran (THF)-water or chloroform (CHCl3)-ethanol dispersions on ITO substrates. The nanoparticle films exhibit consistent and reproducible high optical contrast values of around 50 %, t90-switching speeds of about 0.45 s and a cycling stability of approximately 200 cycles for a 20 % performance retention, independent of the solvent being used. Conversely, non-nanostructured P3HT films spray-coated from THF or CHCl3 reveal a strong solvent dependent variability in their electrochromic behavior presenting low optical contrast, high switching speeds and fast degradation rates in the case of CHCl3. The solvent independent electrochromic characteristics of P3HT nanoparticle films is related to a consistent availability of accessible electroactive sites provided by a homogeneous porous P3HT network structure formed on the underlying substrate, as probed by SEM and profilometric studies. Our findings reveal that the use of nanoparticles of P3HT and its environmentally benign liquid phase processing, a concept which is extendable to other electrochromic polymers, opens a sustainable pathway toward the large-area fabrication of electrochromic device structures with favorable and consistent performance parameters.

[EN] Carbon nanostructures have attracted much attention in recent decades due to their extraordinary electrical and mechanical properties. These properties arise from the sp2 hybridisation of carbon, subsequently forming a wide range of materials. In particular, unidimensional carbon nanostructures may be mainly classified into carbon nanofibers, singlewalled and multi-walled carbon nanotubes. In order to exploit their properties, well defined processing strategies are needed for these nanostructures, preferably in water, which presents a great challenge as they are hydrophobic. Traditionally, non-volatile organic solvents have been used for such purpose, but the use of water as a solvent offers a less toxic and a more sustainable option. However, in order to comply with a full aqueous processing, carbon nanostructures require the use of surfactants, the majority of which are toxic and difficult to remove or their functionalization, thus altering their intrinsic electronic properties. For these reasons, novel and environmentally friendly alternatives are emerging, in particular through the use of natural or biologicallyderived dispersants. Following this trend, we highlight the strategy developed in recent years by the G-CNN group involving cellulose nanocrystals, with a special focus on their applications in biomedicine and conductive inks., [ES] Las nanoestructuras de carbono han cautivado a la comunidad científica en las últimas décadas debido a sus excelentes propiedades eléctricas y mecánicas. Estas propiedades surgen de la hibridación sp2 del carbono, capaz de derivar en una extensa gama de materiales. En particular, las nanoestructuras de carbono unidimensionales se clasifican mayormente en nanofibras de carbono, nanotubos de carbono de pared simple y de pared múltiple. Debido a su naturaleza hidrofóbica, su procesado en fase líquida supone todo un reto, y tradicionalmente se han empleado disolventes orgánicos no volátiles para trabajar con ellas, siendo necesario buscar una alternativa menos tóxica y sostenible como el agua. Sin embargo, para procesarlas en medio acuoso, se necesitan surfactantes, la mayoría de los cuales pueden ser tóxicos y difíciles de eliminar, o si no hay que funcionalizar químicamente las nanoestructuras de carbono, alterando así sus propiedades electrónicas intrínsecas. Por esta razón, están emergiendo nuevas alternativas más sostenibles, en particular mediante el empleo de dispersantes basados en fuentes renovables o biopolímeros. En el contexto de sta estrategia emergente, destacamos las investigaciones realizadas en el grupo de investigación G-CNN, basadas en nanocristales de celulosa, con énfasis en aplicaciones en el campo de la biomedicina o las tintas conductoras.

Chemical structure of the nanostructured biopolymers. Polydispersity results of nanostructured biopolymers. Evolution of the visual appearance of PEs. BNC production with ChNCs without PEs. BNC hydrogels prepared with emulsified culture media.

Covalent functionalization of tungsten disulfide (WS2) with photo- and electro-active nickel-porphyrin (NiP) is reported. Exfoliated WS2 interfacing NiP moieties with 1,2-dithiolane linkages is assayed in the oxygen evolution reaction under both dark and illuminated conditions. The hybrid material presented, WS2−NiP, is fully characterized with complementary spectroscopic, microscopic, and thermal techniques. Standard yet advanced electrochemical techniques, such as linear sweep voltammetry, electrochemical impedance spectroscopy, and calculation of the electrochemically active surface area, are used to delineate the catalytic profile of WS2−NiP. In-depth study of thin films with transient photocurrent and photovoltage response assays uncovers photo-enhanced electrocatalytic behavior. The observed photo-enhanced electrocatalytic activity of WS2−NiP is attributed to the presence of Ni centers coordinated and stabilized by the N4 motifs of tetrapyrrole rings at the tethered porphyrin derivative chains, which work as photoreceptors. This pioneering work opens wide routes for water oxidation, further contributing to the development of non-noble metal electrocatalysts.

Cellulose nanocrystals (CNCs) have aroused increasing interest owing to their renewable origin and excellent properties derived from their size and morphology. Based on their chain orientation, CNCs can be prepared as two main allomorphs (I or II). However, achieving pure CNC allomorphs still requires enhanced control on the CNCs synthesis process and improved understanding of the involved reaction parameters. In this work, we study in detail a set of parameters for CNC synthesis using one-pot acid hydrolysis and evaluate their influence on the outcome with respect to yield, purity, and repeatability. We also demonstrate that a fast, nondestructive, and accurate methodology based on dynamic light scattering is an efficient alternative to the usual structural analysis of the synthesis outcome. Finally, we provide an improved protocol to reliably obtain each allomorph with mass yields of 25% for type I and 40% for type II. Emphasis is put on the reduction of the environmental impact and the overall preparation time.

Nanoparticles (NPs) of conjugated polymers in intimate contact with sheets of graphene oxide (GO) constitute a promising class of water-dispersible nanohybrid materials of increased interest for the design of sustainable and improved optoelectronic thin-film devices, revealing properties exclusively pre-established upon their liquid-phase synthesis. In this context, we report for the first time the preparation of a P3HTNPs–GO nanohybrid employing a miniemulsion synthesis approach, whereby GO sheets dispersed in the aqueous phase serve as a surfactant. We show that this process uniquely favors a quinoid-like conformation of the P3HT chains of the resulting NPs well located onto individual GO sheets. The accompanied change in the electronic behavior of these P3HTNPs, consistently confirmed by the photoluminescence and Raman response of the hybrid in the liquid and solid states, respectively, as well as by the properties of the surface potential of isolated individual P3HTNPs–GO nano-objects, facilitates unprecedented charge transfer interactions between the two constituents. While the electrochemical performance of nanohybrid films is featured by fast charge transfer processes, compared to those taking place in pure P3HTNPs films, the loss of electrochromic effects in P3HTNPs–GO films additionally indicates the unusual suppression of polaronic charge transport processes typically encountered in P3HT. Thus, the established interface interactions in the P3HTNPs–GO hybrid enable a direct and highly efficient charge extraction channel via GO sheets. These findings are of relevance for the sustainable design of novel high-performance optoelectronic device structures based on water-dispersible conjugated polymer nanoparticles.

ZIF8 without and with adsorption of minor amounts of Co precursor have been pyrolized at different temperatures studying systematically the effect of carbonization temperature on the texture, composition and ORR performance both in acidic and basic media. The increase of pyrolysis temperature diminished the N content but increased the graphitic character. The trade-off between these two parameters in metal-free electrocatalysts resulted in an improvement of ORR performance, which is met for the highest pyrolysis temperature of 1000 ºC. Moreover, the adsorption of minor amount of Co precursor enhanced further the ORR performance, increased the graphitic character and the porosity of the resulting carbon material. Morphologically, these carbon materials kept the polyhedral shape of ZIF8 and were covered by graphitic nanostructures devoid of metal nanoparticles. Co metal catalysed the growth of these graphitic nanostructures and concomitantly is stabilized as monoatomic Co-Nx-C species preventing the agglomeration as metal nanoparticles. Therefore, the need of an acid washing step is avoided, which is usually necessary in the carbonization of other metal containing MOFs.

S.1. Experimental details S.2. Characterization of the carbon materials S.2.1. Raman spectroscopy and sheet resistivity S.2.2. X-ray photoelectron spectroscopy (XPS) S.2.3. AFM measurements S.3. The full set of LSV curves in the RRDE S.3.1. Linear sweep voltammetry S.3.2. Koutecky-Levich (KL) analysis S.4. Specific capacitance S.5. Stability tests

Zinc/air batteries are convenient energy storage devices for both small and massive applications. While future perspectives indicate the need for low-cost components and sustainable fabrication processes, the battery performance is in part controlled by the kinetics of the oxygen reduction reaction (ORR), which typically involves transition metals as catalysts. In this context, we prepare a series of metal-free water-based carbon inks, which are tested for their catalytic performance, once deposited on a gas-diffusion substrate, in the air cathode of a simple battery prototype. The inks contain a variety of well-defined carbon nanomaterials and additives, exhibiting different physicochemical properties that critically influence the interaction with the gas diffusion hydrophobic substrate. The intrinsic ORR catalytic activity of the ink material is also analyzed on a glassy carbon electrode by the rotating ring-disc electrode (RRDE) method and specific capacitance measurements. The discharge capacity on our zinc/air battery prototype correlates well with the intrinsic catalytic activity in the RRDE. However, only the activity in the RRDE does not actually assure the performance on the commercial cathode of the prototype, since other chemical compatibility issues play a role. Thus, we highlight the importance of catalyst testing, not only on the RRDE but also under realistic device conditions.

La reducción electroquímica de oxigeno es una reacción de gran importancia para la transición energética ya que está en la base de las pilas de combustible y las baterías de aire. El reto que existe actualmente es aumentar la actividad másica a la vez que evitar o reducir el uso de metales nobles. Especies del tipo metal transición-N-C, que imitan ftalocianinas se han demostrado como una buena alternativa para obtener una alta actividad másica [1] [10]. Estas especias se podrían preparar por la carbonización controlada de MOFs ya que estos contienen tanto metales como nitrógenos atómicamente dispersos. Algunos trabajos pioneros carbonizaron ZIF-67 ) [16] or ZIF-8 [17] con metales. En estos trabajos se realizó un lavado ácido para eliminar las nanopartículas formadas, pero aun así quedaban nanopartículas encapsuladas reduciendo la actividad másica en la ORR. En este trabajo hemos carbonizado ZIF8 con y sin impregnación de 0.9 wt% Co y lo hemos carbonizado a tres temperaturas diferentes, 700 ºC, 900 ºC y 1000 ºC. Los carbones dopados con nitrógeno se han caracterizado exhaustivamente y se han probado en la ORR tanto en medio neutro como básico. De esa manera ha sido posible poner algo de luz el efecto de la temperatura de carbonización y en el efecto de la presencia de Co en las propiedades de los materiales carbonosos y en su comportamiento electrocatalítico en la ORR.

Cellulose nanocrystals (CNCs) are a nanostructured biopolymer with unique properties, such as high strength and water stability. These properties make CNCs ideal for diverse applications, including dispersing agents for hydrophobic carbon nanomaterials in water. Specifically, carbon nanomaterials can be integrated into textiles to produce flexible electronic wearables with excellent performance. However, the necessary prerequisite of achieving stable liquid dispersions of these carbon nanomaterials, such as nanofibers (CNFs) typically involves the use of organic solvents or high concentrations of hazardous surfactants in water. Thus, in this study, for the first time, CNCs were successfully used to prepare CNFs aqueous dispersions, referred to as inks, at CNF concentrations up to 0.7 g L−1. As a proof of principle, these inks were then integrated into a cotton fabric using a facile dip coating and drying strategy, resulting in an e-textile with a negative Seebeck coefficient. Furthermore, a theoretical model was developed to describe the nonlinear Seebeck coefficient of the nanocomposite textile, shedding light on the physics governing the electrical conductivity and Seebeck coefficient over a temperature range from 30 °C to 100 °C. These promising results pave the way towards the development of environmentally friendly and durable CNF aqueous dispersions and wearable e-textiles.

1. General methods 2. Synthetic details 3. Absorption spectra a. Figure S.1. UV-Vis Absorption spectra in CH2Cl2 and concentration dependence of AT-Pyri dye 4. Electrochemical characterization a. Figure S.2. CV analysis of AT-Pyri in CH2Cl2 b. Table S.1. Optical parameters, transition energy E0-0 and potential values Eox and Eox* 5. NMR spectra 6. References

In the vast field of conductive inks, graphene-based nanomaterials, including chemical derivatives such as graphene oxide as well as carbon nanotubes, offer important advantages as per their excellent physical properties. However, inks filled with carbon nanostructures are usually based on toxic and contaminating organic solvents or surfactants, posing serious health and environmental risks. Water is the most desirable medium for any envisioned application, thus, in this context, nanocellulose, an emerging nanomaterial, enables the dispersion of carbon nanomaterials in aqueous media within a sustainable and environmentally friendly scenario. In this work, we present the development of water-based inks made of a ternary system (graphene oxide, carbon nanotubes and nanocellulose) employing an autoclave method. Upon controlling the experimental variables, low-viscosity inks, high-viscosity pastes or self-standing hydrogels can be obtained in a tailored way. The resulting inks and pastes are further processed by spray- or rod-coating technologies into conductive films, and the hydrogels can be turned into aerogels by freeze-drying. The film properties, with respect to electrical surface resistance, surface morphology and robustness, present favorable opportunities as metal-free conductive layers in liquid-phase processed electronic device structures.

A series of nanostructured boron-TiO2 photocatalysts (B-X-TiO2-T) were prepared by sol–gel synthesis using titanium tetraisopropoxide and boric acid. The effects of the synthesis variables, boric acid amount (X) and crystallization temperature (T), on structural and electronic properties and on the photocatalytic performance for propene oxidation, are studied. This reaction accounts for the remediation of pollution caused by volatile organic compounds, and it is carried out at low concentrations, a case in which efficient removal techniques are difficult and costly to implement. The presence of boric acid during the TiO2 synthesis hinders the development of rutile without affecting the textural properties. X-ray photoelectron spectroscopy analysis reveals the interstitial incorporation of boron into the surface lattice of the TiO2 nanostructure, while segregation of B2O3 occurs in samples with high boron loading, also confirmed by X-ray diffraction. The best-performing photocatalysts are those with the lowest boron loading. Their high activity, outperforming the equivalent sample without boron, can be attributed to a high anatase and surface hydroxyl group content and efficient photo-charge separation (photoelectrochemical characterization, PEC), which can explain the suppression of visible photoluminescence (PL). Crystallization at 450 °C renders the most active sample, likely due to the development of a pure anatase structure with a large surface boron enrichment. A shift in the wavelength-dependent activity profile (PEC data) and the lowest electron–hole recombination rate (PL data) are also observed for this sample.

Solar photoelectrolysis of water is considered as a promising route towards green hydrogen production. Since its first demonstration in 1969 [1], improving the efficiency of the process remains the major challenge. Current research efforts focus on the development of improved photoelectrodes enabling higher photocurrents and larger solar-to-hydrogen conversion. Of special interest are photoactive semiconductors being used as photoanodes. Employing concepts of nanostructuring and doping combined with liquid phase technologies for constructing favorable layered configurations, metal oxides offer strategic advantages when it comes towards the use of abundant non-critical materials and sustainable fabrication of efficient large-area photoanodes. Deeper comprehension of the underlying photoelectrochemical processes provides the necessary feedback to a successful progress. In this presentation, boron-doped nanostructured TiO2 film electrodes are used as photoanode. We show that its photoelectrochemical performance can be successfully described by mathematical and physical models. This finding is of wider general interest to understand and improve the performance of nanostructured layered photoanode architectures.

[EN] PHOTOGRAPH is subproject (Ref. PID2019- 104272RB-C51) of a coordinated national project entitled NEXT-ENER, associated at the 2019 national R&D program “Proyectos de I+D+i – Retos” and led by the Group of Carbon Nanostructures and Nanotechnology (G-CNN) at the Instituto de Carboquímica (ICB-CSIC). Within the overall frame of the coordinated project, devoted to the integration of new energy conversion and storage technologies and, being developed by five Spanish research groups, PHOTOGRAPH focuses on the photoelectrochemical hydrogen production using optimized graphene-based interfaces. The main motivation of PHOTOGRAPH is to improve the photoelectrochemical device performance while reducing costs and the ecological footprint, directly tackling several problems that humankind is facing nowadays. In this communication, a journey throughout past, present and future perspectives of PHOTOGRAPH is presented, especially emphasizing ongoing activities., [ES] PHOTOGRAPH es un subproyecto (Ref. PID2019- 104272RB-C51) del proyecto coordinado a nivel nacional titulado NEXT-ENER, asociado al programa nacional de I+D “Proyectos de I+D+i – Retos” de 2019, liderado por el Grupo de Nanoestructuras de Carbono y Nanotecnología. Dentro del marco general del proyecto coordinado, dedicado a la integración de nuevas tecnologías de conversión y almacenamiento de energía y, estando desarrollado por cinco grupos de investigación españoles, PHOTOGRAPH se encarga de la producción fotoelectroquímica de hidrógeno mediante interfaces optimizadas basadas en grafeno. La principal motivación de PHOTOGRAPH es la de mejorar la respuesta de los dispositivos fotoelectroquímicos a la vez que se reduce el coste y la huella ecológica de los mismos, afrontando directamente algunos de los problemas a los que la humanidad se está enfrentando actualmente. En esta comunicación, se hará un recorrido a lo largo del pasado, presente y perspectivas futuras de PHOTOGRAPH, haciendo especial énfasis en las actividades se están llevando a cabo.

Existe un gran interés en trasladar las propiedades de las nanoláminas individuales de grafeno hacia la eescala macroscópica mediante la formación de estructuras porosas 3D. Los aerogeles de grafeno tridimensionales tienen potencial para una amplia gama de aplicaciones gracias a sus múltiples propiedades como alta superficie específica, una red porosa que favorece el transporte iónico, resistencia mecánica y conductividad. Un método de preparar estos aerogeles se basa en la gelificación de dispersiones de óxido de grafeno mediante tratamiento hidrotermal en autoclave. Durante este proceso, se produce el entrecruzamiento de las nanoláminas de óxido de grafeno (GO) gracias a la reducción de los grupos funcionales presentes en ellas. Así, se genera la separación de fases necesaria para formar unhidrogel, que se liofiliza para obtener el aerogel de óxido de grafeno reducido (rGO). En este trabajo, se ha optimizado este proceso para conseguir poros unidireccionales y controlar el tamaño de poro. Estos aerogeles se hanusado como soporte de nanodiamantes o partículas metálicas (Pt, Ru) y se han usado posteriormente como catalizadores en distintas reacciones. Asímismo, se han usado en electroquímica como electrocatalizadores en la reacción de reducción de oxígeno y coo superconductores.

Las cuencas carboníferas, que han sido tan explotadas hasta nuestros días, suelen ser también depósitos de arcillas de notable calidad para la elaboración de cerámica plana (gres), sanitarios, porcelana y, recientemente, nanomateriales de tipo 2D. La explotación de esos depósitos de arcilla puede contribuir a la reconversión de las cuencas mineras, como es el caso de la comarca del mismo nombre, en la provincia de Teruel. El procesado de las arcillas implica frecuentemente la preparación de dispersiones o coloides mediante la adición de defloculantes. Sin embargo, el control de calidad de tales suspensiones coloidales es complejo debido a que se trata de sistemas fuera del equilibrio. Así, sus propiedades, además de depender de los parámetros habituales de composición, temperatura, etc., evolucionan lentamente con el tiempo, lo que dificulta encontrar puntos de referencia en los que realizar medidas reproducibles. En esta comunicación se presentan medidas de viscosidad y conductividad electrolítica en suspensiones concentradas de dos arcillas. Se presta especial atención a la evolución de dichas magnitudes con el tiempo y frente a varias adiciones de silicato de sodio como defloculante.

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.

Explosive percolation is an experimentally-elusive phenomenon where network connectivity coincides with onset of an additional modification of the system; materials with correlated localisation of percolating particles and emergent conductive paths can realise sharp transitions and high conductivities characteristic of the explosively-grown network. Nanocomposites present a structurally- and chemically-varied playground to realise explosive percolation in practically-applicable systems but this is yet to be exploited by design. Herein, we demonstrate composites of graphene oxide and synthetic polymer latex which form segregated networks, leading to low percolation threshold and localisation of conductive pathways. In situ reduction of the graphene oxide at temperatures of <150 °C drives chemical modification of the polymer matrix to produce species with phenolic groups, which are known crosslinking agents. This leads to conductivities exceeding those of dense-packed networks of reduced graphene oxide, illustrating the potential of explosive percolation by design to realise low-loading composites with dramatically-enhanced electrical transport properties.

Two cellulose nanocrystals/single-walled carbon nanotube (CNC/SW) hybrids, using two cellulose polymorphs, were evaluated as electrochemical transducers: CNC type I (CNC-I/SW) and CNC type II (CNC-II/SW). They were synthesized and fully characterized, and their analytical performance as electrochemical sensors was carefully studied. In comparison with SWCNT-based and screen-printed carbon electrodes, CNC/SW sensors showed superior electroanalytical performance in terms of sensitivity and selectivity, not only in the detection of small metabolites (uric acid, dopamine, and tyrosine) but also in the detection of complex glycoproteins (alpha-1-acid glycoprotein (AGP)). More importantly, CNC-II/SW exhibited 20 times higher sensitivity than CNC-I/SW for AGP determination, yielding a LOD of 7 mg L−1.These results demonstrate the critical role played by nanocellulose polymorphism in the electrochemical performance of CNC/SW hybrid materials, opening new directions in the electrochemical sensing of these complex molecules. In general, these high-active-surface hybrids smartly exploited the preserved non-oxidized SW conductivity with the high aqueous dispersibility of the CNC, avoiding the use of organic solvents or the incorporation of toxic surfactants during their processing, making the CNC/SW hybrids promising nanomaterials for electrochemical detection following greener approaches.

La fotocatálisis se suele considerar como una de las posibles alternativas para la producción de hidrógeno verde por escisión de la molécula de agua. En este sentido, además de solventar los problemas de eficiencia en la conversión solar a hidrógeno, es necesario fabricar fotocatalizadores con elementos abundantes y mediante procesos sostenibles, que permitan un escalado de los mismos. En esta comunicación, se presenta la preparación de fotoánodos basados en nanopartículas de TiO2 mediante aerografía, utilizando una tinta que únicamente lleva agua como disolvente y celulosa nanocristalina (NCC) como agente estabilizante. En primera instancia, el TiO2 se depositó sobre óxido de estaño fluorado (FTO), siendo este uno de los sustratos más ampliamente estudiados en aplicaciones solares. Sin embargo, y debido a las dificultades que surgen a la hora de sintetizar dicho compuesto, se propone aquí su sustitución por películas de nanotubos de carbono de capa única (SWCNT) depositadas sobre vidrio. Estas películas de carbono presentan una excelente conductividad superficial, estando además basadas en tintas acuosas estabilizadas con NCC, lo cual hace posible su procesado mediante la técnica de espray.

El dióxido de titanio es muy interesante como fotocatalizador en muchas reacciones de descomposición de contaminantes ya que, además de su excelente capacidad oxidativa, es estable, inocuo, biocompatible y asequible económicamente. Sin embargo, es deseable mejorar su eficiencia fotocatalítica mediante la disminución de la velocidad de recombinación de los pares electrón-hueco, así como ampliar su intervalo de absorción hacia el espectro visible. Una de las potenciales opciones de mejora se centra en la modificación del TiO2 con boro, lo que podría dar lugar a cambios en la energía y ocupación de los estados electrónicos en mitad de la banda prohibida del semiconductor. De acuerdo con esto, en el presente trabajo se han preparado y caracterizado catalizadores B-TiO2 con distintas cantidades de boro, se han tratado a distinta temperatura de cristalización y se ha analizado su actividad en la reacción de fotooxidación de propeno.

Nanostructured biopolymers (NBs) have enhanced properties with respect to their bulk counterparts, due to their smaller size. The main type of NBs are cellulose nanocrystals (CNCs), which are needle-shaped crystals of cellulose with lengths ranging from 100 to 500 nm and diameters around 10 nm. They may be present in different cellulose allomorphs, among which types I and II are the most common.1 Another example of NBs are chitin nanocrystals (ChNCs), being also of similar size and shape as CNCs.2 On the other hand, carbon nanofibers (CNFs), produced by chemical vapor deposition (CVD), and with structures similar to multiwall carbon nanotubes, exhibit interesting transport properties that make them valuable for electronic applications.3 It is for this latter reason that the objective of this study was to disperse commercial as-received CNFs by using NBs as sustainable surfactants to produce aqueous conductive inks. In a first step, various aqueous colloidal dispersions of CNFs and NBs (CNCs, ChNCs) were prepared using ultrasounds as dispersion inducers. Afterwards, centrifugation was used to separate the non-dispersed CNF agglomerates from the final ink (Figure 1). Finally, and as a proof-of-concept, an optimized CNFs/NBs dispersion (namely, ink) was used to prepare films of controlled thicknesses on glass substrates by spray coating. Here, the relationship between the thickness and the surface resistivity (Rsh) was monitored. The results gathered here aim at contributing to the development of more sustainable conductive inks for the fabrication of electronic wearable devices.

Hydrogen is considered as one of the best sustainable alternatives to fossil fuels if produced from water using renewable energy sources. In this context, a promising technology of emerging interest is the photoelectrochemical water splitting, which involves the direct use of luminous energy, ideally sunlight. In a photoelectrolysis cell, at least one electrode (most specifically the anode in this work) contains a photocatalyst material. A typical photoanode configuration consist of fluorine tin oxide (FTO) as a conductive substrate, and TiO2 in anatase phase, which is widely known as one of the most robust semiconductors with a high water oxidation activity. The TiO2 layer is often deposited by screen printing, while spray coating would be a scalable alternative. Due to the characteristics of TiO2 nanoparticles, it is not possible to work with dispersions at neutral pH because they tend to aggregate and precipitate. To overcome this problem, we show that the use of ammonia (NH3) and acetic acid (HAc) as stabilizing agents is one of the best strategies that can be followed to prepare such electrodes by spray coating. Subsequently, photoelectrochemical tests have been performed using a three-electrode cell with sodium sulphate (Na2SO4) as electrolyte. The photoactivity of various as prepared electrodes is compared.

In the vast field of conductive inks, graphene-based nanomaterials, including chemical derivatives such as graphene oxide as well as carbon nanotubes, offer important advantages as per their excellent physical properties. However, inks filled with carbon nanostructures are usually based on toxic and contaminating organic solvents or surfactants, posing serious health and environmental risks. Water is the most desirable medium for any envisioned application, thus, in this context, nanocellulose, an emerging nanomaterial, enables the dispersion of carbon nanomaterials in aqueous media within a sustainable and environmentally friendly scenario. In this work, we present the development of water-based inks made of a ternary system (graphene oxide, carbon nanotubes and nanocellulose) employing an autoclave method. Upon controlling the experimental variables, low-viscosity inks, high-viscosity pastes or self-standing hydrogels can be obtained in a tailored way. The resulting inks and pastes are further processed by spray- or rod-coating technologies into conductive films, and the hydrogels can be turned into aerogels by freeze-drying. The film properties, with respect to electrical surface resistance, surface morphology and robustness, present favorable opportunities as metal-free conductive layers in liquid-phase processed electronic device structures.

Recently, 3D graphene aerogel has garnered a high interest aiming at benefiting of the excellent properties of graphene in devices for energy storage or environmental remediation. Hydrothermal gelation of GO dispersion is a straightforward method that offers many opportunities for tuning its properties and for processing it to devices. By adjusting hydrothermal gelation and drying conditions, it is possible to tune the density (from ~3 mg cm−3 to ~2 g cm−3), pore volume, pores size (micro to macropores), pore distribution, surface chemical polarity (hydrophobic or hydrophilic), and electrical conductivity (from ~0.5 S m−1 to S cm−1). Besides other well explored applications in energy storage or environmental remediation, graphene aerogels have excellent prospects as support for catalysis since they combine the advantages of graphene sheets (high surface area, high electrical conductivity, surface chemistry tunability, high adsorption capacity…) while circumventing their drawbacks such as difficult separation from reaction media or tendency to stacking. Compared to other 3D porous carbon materials used as catalyst support, graphene aerogels have unique porous structure. The pore walls are the thinnest to be expected for a carbon material (the thickness of monolayer graphene is 0.335 nm), hence leading to the highest exposed surface area per weight and even per volume for compacted aerogels. This has the potential to maximize the catalytic site density per reactor mass and volume while minimizing the pressure drop for continuous reactions in flow. Herein, different strategies to control the porous texture, chemical and physical properties are revised along with their processability and scalability for the implementation into different morphologies and devices. Finally, the application of graphene aerogels in the catalysis field are overviewed, giving a perspective about future directions needing further research.

Graphene oxide (GO) is reduced by Joule heating using in-situ transmission electron microscopy (TEM). The approach allows the simultaneous study of GO conductivity by electrical measurements and of its composition and structural properties throughout the reduction process by TEM, electron diffraction and electron energy-loss spectroscopy. The small changes of GO properties observed at low applied electric currents are attributed to the promotion of diffusion processes. The actual reduction process starts from an applied power density of about 2 × 1014 Wm−3 and occurs in a highly uniform and localized manner. The conductivity increases more than 4 orders of magnitude reaching a value of 3 × 103 Sm−1 with a final O content of less than 1%. We discuss differences between the reduction by thermal annealing and Joule heating.

We report an in-depth study of the reduction of graphene oxide (GO) by in-situ thermal transmission electron microscopy (TEM) analysis. In-situ heating high-resolution TEM (HRTEM) imaging and electron energy-loss spectroscopy (EELS) measurements have been combined to identify the transformations of different oxygen functional groups, the desorption of physisorbed and chemisorbed water and the graphitisation as a function of the temperature in the range from 70 up to 1200 °C. A model for the general removal of water and OFGs is proposed based on different chemical and physical parameters that have been monitored. All this unique information provides a detailed roadmap of the thermal behaviour of GO at an extended range of temperature. This is not only of interest to understand the thermal reduction process of GO but also of critical relevance to the response of GO in applications when exposed to thermal effects.

Even though many members from the broad family of carbon nanostructures have been known to us for decades, and despite their promising potential in biology and medicine, there is still a long way ahead to reach the goal of using them in real applications. The cause of such a gap still lies in the persistent drawbacks of insolubility, processability difficulties, poor consistency of macroscopic assemblies and surface inertness of carbon nanostructures. However, solely their direct chemical derivatization might not solve the problem right away. New processing elements need to come into play, but this also twists the whole picture, as the toxicity and performance profiles become more complex. We herein analyse the potential of natural polysaccharides (with a particular focus on cellulose) towards hybrid materials and structures for biomedical purposes. The role that these biopolymers acquire when interfacing with carbon nanostructures goes far beyond a mere dispersing effect, but instead creates unprecedented synergies leading to hydrogels, aerogels, films or fibres with high biocompatibility and bioactivity. In this chapter, the history of carbon nanostructures and natural polysaccharides in the field of biomedical applications will be respectively reviewed, to subsequently go into detail of specific hybrids made with the most relevant biopolymers (namely cellulose, chitin, chitosan and alginate) with extraordinary prospects in biomedicine.

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.

Centrifugation of liquid dispersions is a typical technique being employed to separate single-walled carbon nanotubes (SWCNTs) from big aggregates and impurities. Shining light on the underlying mechanism contributes to a more efficient preparation of corresponding suspensions or inks with improved properties. In this work, we model the sedimentation process by applying fundamental equations and a mathematical algorithm for the centrifugation routine, which takes into account centrifugation parameters and the geometry of nanoparticles. The model is fed with experimental data, namely, the centrifugation mass yield, the SWCNT purity index, metal contents, and nanoparticle sizes measured for pristine, thermally-oxidized, and chemically functionalized SWCNT samples. Particle aggregation, including SWCNT bundling, and changes due to physicochemical pretreatments are taken into account. It is shown that the complete experimental data set can be quantitatively well understood in terms of the particle sedimentation coefficient. The proposed model thus provides a rational concept to optimize centrifugation protocols for the separation of mixtures containing nanoparticles of different shapes.

Green living nanofactories: Nanomaterials (NMs) and nanocomposites are typically prepared by procedures that are incompatible with green chemistry and sustainability principles. But some living entities, from single cells to higher organisms, are able to synthesize and process NMs very efficiently under milder conditions. In this Minireview, the advances and prospects of this growing trend are discussed and summarized., Nanomaterials offer exciting properties and functionalities. However, their production and processing frequently involve complex methods, cumbersome equipment, harsh conditions, and hazardous media. The capability of organisms to accomplish this using mild conditions offers a sustainable, biocompatible, and environmentally friendly alternative. Different nanomaterials such as metal nanoparticles, quantum dots, silica nanostructures, and nanocellulose are being synthesized increasingly through living entities. In addition, the bionanofabrication potential enables also the in situ processing of nanomaterials inside biomatrices with unprecedented outcomes. In this Minireview we present a critical state-of-the-art vision of current nanofabrication approaches mediated by living entities (ranging from unicellular to higher organisms), in order to expand this knowledge and scrutinize future prospects. An efficient interfacial interaction at the nanoscale by green means is within reach through this approach.

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.

Los puntos de carbono poliméricos, pertenecientes a la familia de puntos de carbono (del inglés Carbon Dots), han despertado gran interés en los últimos años por sus excelentes propiedades de fluorescencia, que se puede modificar para que emitan en un rango variado de longitudes de onda. Esto, sumado a su bajo coste de síntesis, gran estabilidad fotoquímica, facilidad de funcionalización, baja toxicidad, elevada biocompatibilidad y solubilidad en agua, los posicionan como una potente alternativa a los puntos cuánticos convencionales, en su mayoría tóxicos por la presencia de metales pesados. Por todo ello, estos materiales resultan muy prometedores para aplicaciones en una gran variedad de campos, como son la biomedicina (diagnóstico, terapia, detección), la fotocatálisis (degradación de contaminantes) y la energía (fotovoltaica) entre otros. Los puntos poliméricos comúnmente emiten en el azul y su mecanismo de fluorescencia ha sido estudiado en profundidad. [5] Sin embargo, se han reportado pocos ejemplos de puntos poliméricos con una emisión de fluorescencia desplazada hacia el rojo. En este trabajo se presenta la producción, optimización y caracterización de puntos poliméricos solubles en agua, con fluorescencia en el verde y elevado rendimiento cuántico. Además, estos puntos poliméricos, implementados sobre un fotoánodo de óxido de titanio, han mejorado la fotoactividad del mismo para procesos de producción limpia de hidrógeno por escisión fotoelectroquímica del agua.

Carbon nanotubes (CNTs), graphene aerogels (GAs), and their hybrid (CNT-GA) prepared by hydrothermal treatment were tested in the electrocatalytic oxygen reduction reaction (ORR). The importance of porous structure derived from the combination of mesoporosity coming from CNTs with macroporosity stemming from GAs was evidenced because the hybrid carbon material exhibited synergistic performance in terms of kinetic current and onset potential. Different electrocatalysts were prepared based on these hybrids doped with nitrogen using different precursors and also supporting Fe nanoparticles. N-doped carbon hybrids showed higher electrocatalytic activity than their undoped counterparts. Nevertheless, both doped and undoped materials provided a mixed two and four electron reduction. On the other hand, the addition of a Fe precursor and phenanthroline to the CNT-GA allowed preparing an N-doped hybrid containing Fe nanoparticles which favored the 4-electron oxygen reduction to water, thus being an excellent candidate as a structured cathode in fuel cells.

Porous carbon materials with hierarchical structure are highly desired for catalytic applications. Commonly, they are prepared by carbonizing a bulk biomass source, controlling the pyrolysis conditions. However, considering the use of nanocrystalline cellulose (NCC) as a building block for its further bottom-up assembly into porous scaffolds, more degrees of freedom to tailor the final porous architecture are allowed. Within this framework, this work proposes to study the NCC self-assembly, aiming for the preparation of fully functional acid catalysts. Hence, a microcrystalline cellulose (MCC) source has been hydrolysed in such a controlled way that results in the selective degradation of the amorphous regions, leaving the nanocrystalline domains intact. The resulting aqueous metastable suspensions of cellulose nanocrystals have been self- assembled into hydrogels. These have been turned into aerogels and subsequently pyrolyzed. A final step was carried out to sulfonate the pyrolized monoliths, rendering porous carbons with anchored sulfonic groups, and therefore emerging as an interesting and greener alternative to homogeneous Brønsted acid catalysts

Commercial methods for the production of green hydrogen are based on alkaline or proton exchange membrane (PEM) electrolysis. Several alternatives are being investigated, including photo-electrochemical water splitting. At a laboratory scale, working electrodes are tipically assembled on ITO of FTO transparent conducting films. Those substrates could be substituted by cheaper more abundant materials. Therefore, we fabricated opaque films of carbon nanotubes (CNTs) to be probed as supports for a photo-active semiconductive oxide, namely nanoparticulate TiO2. Aqueous dispersions of single-walled and multi-walled CNTs were prepared by sonication or stirring in a surfactant (SDBS). The inks were utilized to fabricate conducting electrodes by ultrasounds-assisted spraycoating on glass substrates. Nanoparticulate TiO2 (Aeroxide P25) was deposited on the CNT films by spray-coating of isopropanol suspensions. The TiO2/CNT electrodes were tested in a transient photocurrent experiment in 0.1M Na2SO4 at 0.4V vs. Ag/AgCl. A large capacitance contribution was detected because of CNTs. However, it was clearly demonstrated that an anodic photocurrent is generated under irradiation with a solar simulator (~300 mW·cm-2). While the obtained photocurrents were small ( a few µA·cm-2), the way is open to optimize new architectures for PEC hydrogen generation.

Crystallization under stringent cylindrical confinement leads to novel quasi-one-dimensional materials. Substances with strong cohesive interactions can eventually preserve the symmetries of their bulk phase compatible with the restricted geometry, while those with weak cohesive interactions develop qualitatively different structures. Frozen molecular deuterium (D2), a solid with a strong quantum character, is structurally held by weak dispersive forces. Here, the formation of one-dimensional D2 crystals under carbon nanotube confinement is reported. In contradiction with its weak cohesive interactions, their structures, scrutinized using neutron scattering, correspond to definite cylindrical sections of the hexagonal close-packed bulk crystal. The results are rationalized on the grounds of numerical calculations, which point towards nuclear quantum delocalization as the physical mechanism responsible for the stabilization of such outstanding structures.

The controlled modification of the electronic properties of ZnO nanorods via transition metal doping is reported. A series of ZnO nanorods were synthesized by chemical bath growth with varying Co content from 0 to 20 atomic % in the growth solution. Optoelectronic behavior was probed using cathodoluminescence, time-resolved luminescence, transient absorbance spectroscopy, and the incident photon-to-current conversion efficiency (IPCE). Analysis indicates the crucial role of surface defects in determining the electronic behavior. Significantly, Co-doping extends the light absorption of the nanorods into the visible region, increases the surface defects, shortens the non-radiative lifetimes, while leaving the radiative lifetime constant. Furthermore, for 1 atomic % Co-doping the IPCE of the ZnO nanorods is enhanced. These results demonstrate that doping can controllably tune the functional electronic properties of ZnO nanorods for applications.

Cellulose is a renewable alternative to mass consumption plastics, but its manufacture by the classical methods is not sustainable due to the use of large amounts of strong acids, bases and/or organic species (e.g. ionic liquids) in its production, generating many residues. Bacterial cellulose (BC) has a simpler processing because it is much more cleanly generated. In this work, BC aerogels and xerogels are compared in order to ascertain how the bacterial culture conditions (pH, carbon and nitrogen sources) and the raw hydrogels processing determine their thermal stability, crystallinity index, swelling ratio and flammability. The most notable results are the influence of the drying method on the swelling ratio and the carbon source on the thermal stability. Finally, a feasible application of BC aerogels is presented by treating contaminated water and by capturing water within a non-polar solvent, taking advantage of the dry BC sorption capacity.

Developing highly efficient and stable photoelectrochemical (PEC) water-splitting electrodes via inexpensive, liquid phase processing is one of the key challenges for the conversion of solar energy into hydrogen for sustainable energy production. ZnO represents one the most suitable semiconductor metal oxide alternatives because of its high electron mobility, abundance, and low cost, although its performance is limited by its lack of absorption in the visible spectrum and reduced charge separation and charge transfer efficiency. Here, we present a solution-processed water-splitting photoanode based on Co-doped ZnO nanorods (NRs) coated with a transparent functionalizing metal–organic framework (MOF). The light absorption of the ZnO NRs is engineered toward the visible region by Co-doping, while the MOF significantly improves the stability and charge separation and transfer properties of the NRs. This synergetic combination of doping and nanoscale surface functionalization boosts the current density and functional lifetime of the photoanodes while achieving an unprecedented incident photon to current efficiency (IPCE) of 75% at 350 nm, which is over 2 times that of pristine ZnO. A theoretical model and band structure for the core–shell nanostructure is provided, highlighting how this nanomaterial combination provides an attractive pathway for the design of robust and highly efficient semiconductor-based photoanodes that can be translated to other semiconducting oxide systems.

Electrically conductive graphene aerogels are attracting great interest as functional materials. Nevertheless, graphene aerogels synthesized from graphene oxide usually exhibit low electrical conductivity. In order to increase conductivity, herein a postsynthesis thermal treatment at several temperatures (from 300 to 1000 °C) has been applied to pristine reduced graphene oxide aerogels under two different atmospheres, namely, inert Ar flow and isopropanol+H2 flow. Upon thermal treatment under Ar flow, the electrical conductivity of aerogel upscales with the treatment temperature. More remarkably, the electrical conductivity becomes 1 order of magnitude larger when the thermal treatment is carried out under isopropanol+H2 instead of under Ar, while maintaining a very low density and porous structure. The electrical conductivity achieved is exceptionally high for such a lightweight and porous material. The exhaustive characterization allowed disclosing that the generation of carbon links between the reduced graphene oxide nanosheets is the reason for this enhancement. The electrically conductive aerogels have excellent prospects for application as scaffolds for energy storage or biomedical applications.

Carbon nanotubes (CNTs) processed into conductive films by liquid phase deposition technologies reveal increasing interest as electrode components in electrochemical device platforms for sensing and energy storage applications. In this work we show that the addition of acrylic latex to water-based CNT inks not only favors the fabrication of stable and robust flexible electrodes on plastic substrates but, moreover, sensitively enables the control of their electrical and electrochemical transport properties. Importantly, within a given concentration range, the acrylic additive in the films, being used as working electrodes, effectively blocks undesired faradaic transfer reactions across the electrode–electrolyte interface while maintaining their capacitance response as probed in a three-electrode electrochemical device configuration. Our results suggest a valuable strategy to enhance the chemical stability of CNT film electrodes and to suppress non-specific parasitic electrochemical reactions of relevance to electroanalytical and energy storage applications.

Controlling the physicochemical properties of nanoparticles in fluids directly impacts on their liquid phase processing and applications in nanofluidics, thermal engineering, biomedicine and printed electronics. In this work, the temperature dependent viscosity of various aqueous nanofluids containing carbon nanotubes (CNTs) or graphene oxide (GO), i.e. 1D and 2D nanoparticles with extreme aspect ratios, is analyzed by empirical and predictive physical models. The focus is to understand how the nanoparticle shape, concentration, motion degrees and surface chemistry affect the viscosity of diluted dispersions. To this end, experimental results from capillary viscosimeters are first examined in terms of the energy of viscous flow and the maximum packing fraction applying the Maron-Pierce model. Next, a comparison of the experimental data with predictive physical models is carried out in terms of nanoparticle characteristics that affect the viscosity of the fluid, mostly their aspect ratio. The analysis of intrinsic viscosity data leads to a general understanding of motion modes for carbon nanoparticles, including those with extreme aspect ratios, in a flowing liquid. The resulting universal curve might be extended to the prediction of the viscosity for any kind of 1D and 2D nanoparticles in dilute suspensions.

Various types of fluorescent carbon nanoparticles, often called carbon dots (CDs), are synthesized by different polycondensation methods: microwave irradiation, hydrothermal conditions or solution chemistry at ambient temperature with subsequent chemical functionalization. The CDs are deposited on TiO2 films to be probed as electron transport layers in perovskite photovoltaics and the anode for photoelectrochemical water splitting. Nitrogen CDs, which do not contain oxygen, lead to an increase of around 50 mV in the open circuit voltage of perovskite solar cells. All the CD types produce an improved photocurrent in water splitting, particularly CDs that are functionalized with thiol groups and butyl chains. It is demonstrated that the modified electrode is stable under continuous operation. Other electrochemical characteristics of the electrode, such as the voltammogram shape, onset potentials and open circuit potentials, remain nearly unchanged upon the deposition of CDs. Only the incident photon to current conversion efficiency improves clearly, extending the absorption range by around 20 nm towards longer wavelengths. This study provides new data about mechanisms and electrode arrangements for improving the performance of n-type semiconductors in photovoltaic cells and photoelectrochemical hydrogen production.

The preparation of MoS 2 ‐polymer carbon nanodot (MoS 2 ‐PCND) hybrid material was accomplished by employing an easy and fast bottom‐up synthetic approach. Specifically, MoS 2 ‐PCND was realized by the thermal decomposition of ammonium tetrathiomolybdate and the in‐situ complexation of Mo with carboxylic acid units present in the surface of PCNDs. The newly prepared hybrid material was comprehensively characterized by spectroscopic, thermal and electron microscopy imaging means. The electrocatalytic activity of MoS 2 ‐PCND was examined against the hydrogen evolution reaction (HER) and compared with that attributed to the hybrid material prepared by a top‐down approach, namely with MoS 2 ‐PCND(exf‐fun), in which MoS 2 was firstly exfoliated and then covalently functionalized with PCNDs. The MoS 2 ‐PCND hybrid material showed superior electrocatalytic activity against HER with low Tafel slope value and excellent electrocatalytic stability, with an onset potential at ‐0.16 V vs RHE. The superior catalytic performance of MoS 2 ‐PCND was rationalized by considering the catalytic active sites of MoS 2 , the effective charge/energy‐transfer phenomena from PCNDs to MoS 2 and the synergetic effect between MoS 2 and PCNDs within the hybrid material.

Graphene has attracted enormous interest in the scientific community as the first 2D material with exceptional mechanical, electronic and thermal properties. Pristine Graphene is notoriously difficult to process for macroscale applications, to overcome this many people use graphene oxide (GO) instead. GO is water soluble and easily functionalised and so can be simply processed into various systems. GO lacks the exceptional electronic properties of graphene due to structural disorder, therefore an important area of research is on the reduction of GO, which partly restores the structure and properties of graphene. Various techniques have been developed to perform the reduction step. We report a simple approach for preparing conductive Polymer Latex-rGO composites by using a latex-assembly method. After a treatment in the oven at low T, we can reduce the GO in situ. We make use of the inherent GO properties to optimise the aqueous composite fabrication, which is scalable and adaptable, and then restore conductivity with a simple, low temperature, heating step; opening up pathways to tunable electronic composite materials on a large scale.