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Protein crystallization remains a major bottleneck for the determination of high resolution structures. Nucleants can accelerate the process but should ideally be compatible with high throughput robotic screening. Polyethylene glycol grafted (PEGylated) graphenes can be stabilized in water providing dispensable, nucleant systems. Two graphitic feedstocks are exfoliated and functionalized with PEG using a non‐destructive, scalable, chemical reduction method, delivering good water dispersibility (80 and 750 µg mL−1 for large and small layers, respectively). The wide utility of these nucleants has been established across five proteins and three different screens, each of 96 conditions, demonstrating greater effectiveness of the dispersed PEGylated graphenes. Smaller numbers of larger, more crystalline flakes consistently act as better protein nucleants. The delivered nucleant concentration is optimized (0.1 mg mL−1 in the condition), and the performance benchmarked against existing state of the art, molecularly imprinted polymer nucleants. Strikingly, graphene nucleants are effective even when decreasing both the nucleant and protein concentration to unusually low concentrations. The set‐up to scale‐up nucleant production to liter volumes can provide sufficient material for wide implementation. Together with the optimized crystallization conditions, the results are a step forward toward practical synthesis of a readily accessible "universal" nucleant. [ABSTRACT FROM AUTHOR]

Nanomaterials, such as single‐walled carbon nanotubes (SWCNTs) and graphenes, can be readily gelled using bi‐ or multi‐functional reagents as crosslinkers. This study reports a new reaction of monofunctional acetylenes with negatively charged SWCNTs (nanotubides), prepared by reduction. Mono‐acetylenes (e. g. phenylacetylene (PAc) and diphenyl acetylene (DiPAc)) are introduced as crosslinkers to form all‐carbon SWCNT organogels at room temperature. The resulting isolated SWCNT aerogels have a density of ∼4.5–5.5 mg cm−3. Raman spectroscopy and thermogravimetric analysis suggest a covalent surface modification (∼1 functional group per 110 (PAc) and 712 (DiPAc) SWCNT carbon atoms). Significantly, the acetylene reaction does not consume all available negative charges. The SWCNT organogel is still reactive after crosslinking and can reduce a stable gold complex, chloro(triphenylphosphine)gold (I), to form AuNPs (∼12–14 nm), suggesting the formation of a living nanotubide organogel intermediate, suitable for a range of secondary reactions. Mono‐acetylenes can crosslink other negatively charged molecular systems, and surface decoration of the aerogels with other metal NPs is anticipated. [ABSTRACT FROM AUTHOR]

Graphite intercalation compounds (GICs) are often used to produce exfoliated or functionalised graphene related materials (GRMs) in a specific solvent. This study explores the formation of the Na‐tetrahydrofuran (THF)‐GIC and a new ternary system based on dimethylacetamide (DMAc). Detailed comparisons of in situ temperature dependent XRD with TGA‐MS and Raman measurements reveal a series of dynamic transformations during heating. Surprisingly, the bulk of the intercalation compound is stable under ambient conditions, trapped between the graphene sheets. The heating process drives a reorganisation of the solvent and Na molecules, then an evaporation of the solvent; however, the solvent loss is arrested by restacking of the graphene layers, leading to trapped solvent bubbles. Eventually, the bubbles rupture, releasing the remaining solvent and creating expanded graphite. These trapped dopants may provide useful property enhancements, but also potentially confound measurements of grafting efficiency in liquid‐phase covalent functionalization experiments on 2D materials. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) layered graphitic carbon nitride (gCN) nanosheets offer intriguing electronic and chemical properties. However, the exfoliation and functionalisation of gCN for specific applications remain challenging. We report a scalable one‐pot reductive method to produce solutions of single‐ and few‐layer 2D gCN nanosheets with excellent stability in a high mass yield (35 %) from polytriazine imide. High‐resolution imaging confirmed the intact crystalline structure and identified an AB stacking for gCN layers. The charge allows deliberate organic functionalisation of dissolved gCN, providing a general route to adjust their properties. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (GNP) were exfoliated using a nondestructive chemical reduction method and subsequently decorated with polymers using two different approaches: grafting from and grafting to. Poly(methyl methacrylate) (PMMA) with varying molecular weights was covalently attached to the GNP layers using both methods. The grafting ratios were higher (44.6% to 126.5%) for the grafting from approach compared to the grafting to approach (12.6% to 20.3%). The products were characterized using thermogravimetric analysis-mass spectrometry (TGA-MS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The grafting from products showed an increase in the grafting ratio and dispersibility in acetone with increasing monomer supply; on the other hand, due to steric effects, the grafting to products showed lower absolute grafting ratios and a decreasing trend with increasing polymer molecular weight. The excellent dispersibility of the grafting from functionalized graphene, 900 μg/mL in acetone, indicates an increased compatibility with the solvent and the potential to increase graphene reinforcement performance in nanocomposite applications. [ABSTRACT FROM AUTHOR]

The Joule heating properties of an ultralight nanocarbon aerogel are investigated with a view to potential applications as energy-efficient, local gas heater, and other systems. Thermally reduced graphene oxide (rGO) aerogels (10 mg cm−3) with defined shape are produced via emulsion-templating. Relevant material properties, including thermal conductivity, electrical conductivity and porosity, are assessed. Repeatable Joule heating up to 200 °C at comparatively low voltages (≈1 V) and electrical power inputs (≈2.5 W cm−3) is demonstrated. The steady-state core and surface temperatures are measured, analyzed and compared to analogous two-dimensional nanocarbon film heaters. The assessment of temperature uniformity suggests that heat losses are dominated by conductive and convective heat dissipation at the temperature range studied. The radial temperature gradient of an uninsulated, Joule-heated sample is analyzed to estimate the aerogel's thermal conductivity (around 0.4 W m−1 K−1). Fast initial Joule heating kinetics and cooling rates (up to 10 K s−1) are exploited for rapid and repeatable temperature cycling, important for potential applications as local gas heaters, in catalysis, and for regenerable of solid adsorbents. These principles may be relevant to wide range of nanocarbon networks and applications. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) show great potentialas CO2adsorbent materials, but require improvements instabilityand CO2adsorption capacity for commercial applications.In the current study, graphene oxide provides a light-weight, charge-complementary,two-dimensional (2D) material that interacts effectively with the2D LDHs, in turn enhancing the CO2uptake capacity andmulticycle stability of the assembly. As a result, the absolute capacityof the LDH was increased by 62% using only 7 wt % grapheneoxide (GO) as a support. The experimental procedure for the synthesisof the materials is based on a direct precipitation of the LDH nanoparticlesonto GO followed by a structural and physical characterization byelectron microscopy, X-ray diffraction, thermogravimetric analysis,and Brunauer–Emmett–Teller (BET) surface area measurements.Detailed titration confirmed the compatibility of the surface chemistry.After thermal decomposition, mixed metal oxides (MMOs) are obtainedwith the basic sites required for the CO2adsorption. Arange of samples with different proportions of GO/MMO were prepared,fully characterized, and correlated with the CO2sorptioncapacity, established via TGA. [ABSTRACT FROM AUTHOR]

Solutions of negatively charged graphene (graphenide) platelets were produced by intercalation of nanographite with liquid potassium-ammonia followed by dissolution in tetrahydrofuran. The structure and morphology of these solutions were then investigated by small-angle neutron scattering. We found that >95 vol % of the solute is present as single-layer graphene sheets. These charged sheets are flat over a length scale of >150 Å in solution and are strongly solvated by a shell of solvent molecules. Atomic force microscopy on drop-coated thin films corroborated the presence of monolayer graphene sheets. Our dissolution method thus offers a significant increase in the monodispersity achievable in graphene solutions. [ABSTRACT FROM AUTHOR]

Polymer electrolyte fuel cells hold great promise for a range of applications but require advances in durability for widespread commercial uptake. Corrosion of the carbon support is one of the main degradation pathways; hence, corrosion-resilient graphene has been widely suggested as an alternative to traditional carbon black. However, the performance of bulk graphene-based electrodes is typically lower than that of commercial carbon black due to their stacking effects. This article reports a simple, scalable and non-destructive method through which the pore structure and platinum utilisation of graphene-based membrane electrode assemblies can be significantly improved. Urea is incorporated into the catalyst ink before deposition, and is then simply removed from the catalyst layer after spraying by submerging the electrode in water. This additive hinders graphene restacking and increases porosity, resulting in a significant increase in Pt utilisation and current density. This technique does not require harsh template etching and it represents a pathway to significantly improve graphene-based electrodes by introducing hierarchical porosity using scalable liquid processes. [ABSTRACT FROM AUTHOR]

Keywords: 2D materials; exfoliation; graphene; graphite intercalation compounds; X-ray diffraction EN 2D materials exfoliation graphene graphite intercalation compounds X-ray diffraction 6291 6291 1 05/23/20 20200520 NES 200520 B Graphite Intercalation compounds (GICs) b are often used to produce exfoliated or functionalized graphene related materials in a specific solvent. 2D materials, exfoliation, graphene, graphite intercalation compounds, X-ray diffraction. [Extracted from the article]

On page 28, a fundamental study of the direct resistive heating of emulsion‐templated graphene aerogels demonstrates reliable, fast, energy‐efficient and uniform temperature control of the graphene framework. R. Menzel, M. S. P. Shaffer, and team's findings lay a framework that may be exploited in a wide range of novel applications for nanocarbon aerogels, including flow‐through local gas heaters, temperature‐sensitive catalytic reactions, and thermally regenerable filter and storage systems. [ABSTRACT FROM AUTHOR]