Exploring Zinc-Doped Manganese Hexacyanoferrate as Cathode for Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (AZiBs) have emerged as a promising alternative to lithium-ion batteries as energy storage systems from renewable sources. Manganese hexacyanoferrate (MnHCF) is a Prussian Blue analogue that exhibits the ability to insert divalent ions such as Zn. However, in an aqueous environment, MnHCF presents weak structural stability and suffers from manganese dissolution.

Two-Dimensional MoS Nanosheets Derived from Cathodic Exfoliation for Lithium Storage Applications.

The preparation of 2H-phase MoS thin nanosheets by electrochemical delamination remains a challenge, despite numerous efforts in this direction. In this work, by choosing appropriate intercalating cations for cathodic delamination, the insertion process was facilitated, leading to a higher degree of exfoliation while maintaining the original 2H-phase of the starting bulk MoS material. Specifically, trimethylalkylammonium cations were tested as electrolytes, outperforming their bulkier tetraalkylammonium counterparts, which have been the focus of past studies.

NbSe Nanosheets/Nanorolls Obtained via Fast and Direct Aqueous Electrochemical Exfoliation for High-Capacity Lithium Storage.

Layered transition-metal dichalcogenides (LTMDs) in two-dimensional (2D) form are attractive for electrochemical energy storage, but research efforts in this realm have so far largely focused on the best-known members of such a family of materials, mainly MoS, MoSe, and WS. To exploit the potential of further, currently less-studied 2D LTMDs, targeted methods for their production, preferably by cost-effective and sustainable means, as well as control over their nanomorphology, are highly desirable. Here, we report a quick and straightforward route for the preparation of 2D NbSe and other metallic 2D LTMDs that relies on delaminating their bulk parent solid under aqueous cathodic conditions.

Influence of the properties of different graphene-based nanomaterials dispersed in polycaprolactone membranes on astrocytic differentiation.

Composites of polymer and graphene-based nanomaterials (GBNs) combine easy processing onto porous 3D membrane geometries due to the polymer and cellular differentiation stimuli due to GBNs fillers. Aiming to step forward to the clinical application of polymer/GBNs composites, this study performs a systematic and detailed comparative analysis of the influence of the properties of four different GBNs: (i) graphene oxide obtained from graphite chemically processes (GO); (ii) reduced graphene oxide (rGO); (iii) multilayered graphene produced by mechanical exfoliation method (G); and (iv) low-oxidized graphene via anodic exfoliation (G); dispersed in polycaprolactone (PCL) porous membranes to induce astrocytic differentiation. PCL/GBN flat membranes were fabricated by phase inversion technique and broadly characterized in morphology and topography, chemical structure, hydrophilicity, protein adsorption, and electrical properties.

Cytotoxicity of Nucleotide-Stabilized Graphene Dispersions on Osteosarcoma and Healthy Cells: On the Way to Safe Theranostics Agents.

An appealing strategy that overcomes the hydrophobicity of pristine graphene and favors its interaction with biological media is colloidal stabilization in aqueous medium with the support of a biomolecule, such as flavin mononucleotide (FMN), as exfoliating/dispersing agent. However, to establish FMN-stabilized graphene (PG-FMN) as suitable for use in biomedicine, its biocompatibility must be proved by a complete assessment of cytotoxicity at the cellular level. Furthermore, if PG-FMN is to be proposed as a theranostic agent, such a study should include both healthy and tumoral cells and its outcome should reveal the nanomaterial as selectively toxic to the latter.

A Simple and Expeditious Route to Phosphate-Functionalized, Water-Processable Graphene for Capacitive Energy Storage.

Phosphate-functionalized carbon-based nanomaterials have attracted significant attention in recent years owing to their outstanding behavior in electrochemical energy-storage devices. In this work, we report a simple approach to obtain phosphate-functionalized graphene (PFG) via anodic exfoliation of graphite at room temperature with a high yield. The graphene nanosheets were obtained via anodic exfoliation of graphite foil using aqueous solutions of HPO or NaPO in the dual role of phosphate sources and electrolytes, and the underlying exfoliation/functionalization mechanisms are proposed.

Boosting the Performance of Graphene Cathodes in Na-O Batteries by Exploiting the Multifunctional Character of Small Biomolecules.

Graphene aerogels derived from a biomolecule-assisted aqueous electrochemical exfoliation route are explored as cathode materials in sodium-oxygen (Na-O ) batteries. To this end, the natural nucleotide adenosine monophosphate (AMP) is used in the multiple roles of exfoliating electrolyte, aqueous dispersant, and functionalizing agent to access high quality, electrocatalytically active graphene nanosheets in colloidal suspension (bioinks). The surface phenomena occurring on the electrochemically derived graphene cathode is thoroughly studied to understand and optimize its electrochemical performance, where a cooperative effect between the nitrogen atoms and phosphates from the AMP molecules is demonstrated.

Macrophage inflammatory and metabolic responses to graphene-based nanomaterials differing in size and functionalization.

The preparation of graphene-based nanomaterials (GBNs) with appropriate stability and biocompatibility is crucial for their use in biomedical applications. In this work, three GBNs differing in size and/or functionalization have been synthetized and characterized, and their in vitro biological effects were compared. Pegylated graphene oxide (GO-PEG, 200-500 nm) and flavin mononucleotide-stabilized pristine graphene with two different sizes (PG-FMN, 200-400 nm and 100-200 nm) were administered to macrophages, chosen as cellular model due to their key role in the processing of foreign materials and the regulation of inflammatory responses.

High Performance Na-O Batteries and Printed Microsupercapacitors Based on Water-Processable, Biomolecule-Assisted Anodic Graphene.

Integrated approaches that expedite the production and processing of graphene into useful structures and devices, particularly through simple and environmentally friendly strategies, are highly desirable in the efforts to implement this two-dimensional material in state-of-the-art electrochemical energy storage technologies. Here, we introduce natural nucleotides (e.g.

Aqueous Cathodic Exfoliation Strategy toward Solution-Processable and Phase-Preserved MoS Nanosheets for Energy Storage and Catalytic Applications.

The production of MoS nanosheets by electrochemical exfoliation routes holds great promise as a means to access this two-dimensional material in large quantities for different practical applications. However, the use of electrolytes based on synthetic organic salts and solvents, as well as issues related to the unwanted oxidation and/or phase transformation of the exfoliated nanosheets, constitute significant obstacles that hinder the industrial adoption of the electrochemical approach. Here, we introduce a safe and sustainable method for the cathodic delamination of MoS that makes use of aqueous solutions of very simple and widely available salts, mainly KCl, as the electrolyte.

Electrospun silk fibroin scaffolds coated with reduced graphene promote neurite outgrowth of PC-12 cells under electrical stimulation.

Novel approaches to neural research require biocompatible materials capable to act as electrode structures or scaffolds for tissue engineering in order to stimulate or restore the functionality of damaged tissues. This work offers promising results that indicate the potential use of electrospun silk fibroin (SF) scaffolds coated with reduced graphene oxide (rGO) in this sense. The coated material becomes conductor and electroactive.

Aqueous Exfoliation of Transition Metal Dichalcogenides Assisted by DNA/RNA Nucleotides: Catalytically Active and Biocompatible Nanosheets Stabilized by Acid-Base Interactions.

The exfoliation and colloidal stabilization of layered transition metal dichalcogenides (TMDs) in an aqueous medium using functional biomolecules as dispersing agents have a number of potential benefits toward the production and practical use of the corresponding two-dimensional materials, but such a strategy has so far remained underexplored. Here, we report that DNA and RNA nucleotides are highly efficient dispersants in the preparation of stable aqueous suspensions of MoS and other TMD nanosheets at significant concentrations (up to 5-10 mg mL). Unlike the case of common surfactants, for which adsorption on 2D materials is generally based on weak dispersive forces, the exceptional colloidal stability of the TMD flakes was shown to rely on the presence of relatively strong, specific interactions of Lewis acid-base type between the DNA/RNA nucleotide molecules and the flakes.

Impact of Covalent Functionalization on the Aqueous Processability, Catalytic Activity, and Biocompatibility of Chemically Exfoliated MoS Nanosheets.

Chemically exfoliated MoS (ce-MoS) has emerged in recent years as an attractive two-dimensional material for use in relevant technological applications, but fully exploiting its potential and versatility will most probably require the deployment of appropriate chemical modification strategies. Here, we demonstrate that extensive covalent functionalization of ce-MoS nanosheets with acetic acid groups (∼0.4 groups grafted per MoS unit) based on the organoiodide chemistry brings a number of benefits in terms of their processability and functionality.

From graphene oxide to pristine graphene: revealing the inner workings of the full structural restoration.

High temperature annealing is the only method known to date that allows the complete repair of a defective lattice of graphenes derived from graphite oxide, but most of the relevant aspects of such restoration processes are poorly understood. Here, we investigate both experimentally (scanning probe microscopy) and theoretically (molecular dynamics simulations) the thermal evolution of individual graphene oxide sheets, which is rationalized on the basis of the generation and the dynamics of atomic vacancies in the carbon lattice. For unreduced and mildly reduced graphene oxide sheets, the amount of generated vacancies was so large that they disintegrated at 1773-2073 K.

Chemically exfoliated MoS₂ nanosheets as an efficient catalyst for reduction reactions in the aqueous phase.

Chemically exfoliated MoS2 (ce-MoS2) nanosheets that incorporate a large fraction of metallic 1T phase have been recently shown to possess a high electrocatalytic activity in the hydrogen evolution reaction, but the potential of this two-dimensional material as a catalyst has otherwise remained mostly uncharted. Here, we demonstrate that ce-MoS2 nanosheets are efficient catalysts for a number of model reduction reactions (namely, those of 4-nitrophenol, 4-nitroaniline, methyl orange, and [Fe(CN)6](3-)) carried out in aqueous medium using NaBH4 as a reductant. The performance of the nanosheets in these reactions is found to be comparable to that of many noble metal-based catalysts.

Adsorption of n-alkanes on plasma-oxidized high-strength carbon fibers.

The objective of this work was to characterize the degree of heterogeneity brought about by oxygen plasma treatment of carbon fibers by studying its effects on the adsorption of n-alkanes. Untreated and unsized high-strength carbon fibers were subjected to oxygen plasma treatments with different degrees of severity. A sample of the same material oxidized following a standard industrial method was also studied for comparison.