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Graphene is a perfect 2D crystal of covalently bonded carbon atoms and constitutes the building block for all graphitic structures. Its superior properties make it an attractive material for a variety of technological applications. However, mass production does not meet the initial expectations. Chemical Vapor Deposition (CVD) is currently the only available method for large‐scale automated production, but the produced graphene sheets suffer from structural and morphological defects that degrade considerably the mechanical and other physical properties of synthesized graphene. Recently, the use of liquid metal catalysts (LMCat) has been proposed as an alternative platform for facile and high‐quality synthesis of single‐crystal graphene. Herein, simultaneous Raman spectroscopy combined with mechanical testing is adopted confirming that the reinforcing efficiency of the LMCat graphene is greatly improved. In fact, the effective Young's modulus of LMCat graphene has been found ≈630 GPa, which is significantly higher than the graphene grown on solid Cu substrate due to differences in the morphology of Cu substrate. Overall, this work paves the way for the development of defect‐free graphene of quality comparable to exfoliated flakes, and this will have a major technological impact for many applications. [ABSTRACT FROM AUTHOR]

Agglomerations effects of graphene‐based nanofillers are often reported in the literature to be the main reason on the deterioration of the mechanical properties, especially at high filler loadings. In our study, we focused on the correlated effects of plasma‐treated graphene nanofillers on the curing reaction and mechanical properties of an epoxy matrix. Specifically, we explored the effect of dispersion state, planar size, filler content, surface functionalization and stoichiometric ratio on the epoxy curing process. The surface of the treated graphene nanofillers were studied in detail by X‐ray photoelectron spectroscopy (XPS), Raman spectroscopy and X‐ray diffraction (XRD). The results indicated greater presence of oxygen containing groups with the crystallinity to be unaffected after the plasma process. Dynamic Mechanical Analysis (DMA) was used to assess the changes in both the Tg and the mechanical properties of graphene‐epoxy nanocomposites. Rheological and microscopic data showed that a well‐dispersed material was achieved at high filler loadings with the use of calendaring and plasma functionalization. Although, a well‐dispersed material was achieved on the bulk composite, no further mechanical reinforcement was observed at high filler loadings. The adsorption of epoxy groups onto the graphene nanofillers' surface, leading to a stoichiometric imbalance between the epoxy chains and hardener molecules, was proposed to explain the results. [ABSTRACT FROM AUTHOR]

Laser‐fabrication of graphene from cellulose‐based feedstock materials often requires extensive preprocessing. This work demonstrates laser fabrication of porous, 3D graphene from a new class of marine‐based sustainable materials–chitosan biopolymers. The biopolymer films contain only chitosan, acetic acid, glycerol, and water. Fourier transform infrared spectroscopy studies indicate that the cured chitosan films still retain a significant water content (≈30%), enabling production of flexible films. A simple 3‐step laser fabrication process is presented using low‐cost infrared (CO2, 2.1 W) and visible (405 nm, 0.5 W) hobbyist laser engravers, with measured sheet resistance values as low as 40 ohms sq.−1. Transient electrochemical detection of an inner sphere redox molecule is demonstrated using a graphene‐like carbon working electrode fabricated on a water‐soluble chitosan substrate. [ABSTRACT FROM AUTHOR]

As the power‐conversion efficiency (PCE) of organic–inorganic lead halide perovskite solar cells (PSCs) is approaching the theoretical maximum, the most crucial issue concerns long‐term ambient stability. Here, the application of PCN‐224 quantum dots (QDs) is reported, a typical Zr‐based porphyrinic metal–organic framework (MOF), to enhance the ambient stability of PSCs. PCN‐224 QDs with abundant Lewis‐base groups (e.g., CO, C−N, CN) contribute to high‐quality perovskite films with enlarged grain size and reduced defect density by interaction with under‐coordinated Pb2+. Meanwhile, PCN‐224 QDs enable the well‐matched energy level at the perovskite/hole transport layer (HTL) interface, thereby facilitating hole extraction and transport. More importantly, PCN‐224 QDs‐treated HTL can capture Li+ from bis(trifluoromethanesulfonyl)imide additive, leading to the reduced aggregation and less direct contact with moisture for hygroscopic Li‐TFSI. Moreover, PCN‐224 QDs mitigated Li+ ion migration into the perovskite layer, thus avoiding the formation of deleterious defects. The resultant devices yield a champion PCE of 22.51%, along with substantially improved durability, including humidity, thermal and light soaking stabilities. The findings provide a new approach toward efficient and stable PSCs by applying MOF QDs. [ABSTRACT FROM AUTHOR]

The development of innovative materials for preventive conservation of cultural objects against known threats, such as fungi and volatile organic compounds (VOCs) that often exist in museums and galleries, is still challenging. In this work, graphene‐based aerogels with an ionic liquid (IL) additive were prepared, and their anti‐fungal and VOCs absorption properties were investigated. Several IL contents were evaluated and the graphene aerogel containing 10 wt.% IL was found to have the best anti‐fungal activity, preventing the aerogel contamination with Aspergillus niger. When exposed to a VOC saturated micro‐environment, this aerogel was highly suitable for the absorption of acetaldehyde, formic acid, acetic acid, and formaldehyde. This combined anti‐fungal and VOC absorption properties are prerequisites for bringing preventive conservation to a higher level. [ABSTRACT FROM AUTHOR]

The mechanical performance of fiber‐reinforced composites is seriously affected by their exposure to the environment. The combined action of elevated temperatures, humidity, and UV radiation (aging) on aramid fibers/epoxy resin composites is examined by employing Raman spectroscopy in tandem with mechanical loading. The imposed conditions drastically affect the interface of the composites altering the performance of the material under tensile loads. Although the maximum values of interfacial shear strength for the aged material are similar to that of the pristine material; however, they appear at lower strain levels, which is attributed to the significant decrease of the shear modulus of the epoxy matrix combined with the failure of aramid fibers to sustain the external loading due to the aging process. At high strains, the interface fails at lower strain levels (compared to the pristine sample) due to significant increase of micro‐cracking and micro‐voids on the surface of the aged composites. The formation of such flaws is the primary reason for the reduced mechanical performance and early failure of the composite material. [ABSTRACT FROM AUTHOR]

Carbon is a simple, stable and popular element with many allotropes. The carbon family members include carbon dots, carbon nanotubes, carbon fibers, graphene, graphite, graphdiyne and hard carbon, etc. They can be divided into different dimensions, and their structures can be open and porous. Moreover, it is very interesting to dope them with other elements (metal or non‐metal) or hybridize them with other materials to form composites. The elemental and structural characteristics offer us to explore their applications in energy, environment, bioscience, medicine, electronics and others. Among them, energy storage and conversion are extremely attractive, as advances in this area may improve our life quality and environment. Some energy devices will be included herein, such as lithium‐ion batteries, lithium sulfur batteries, sodium‐ion batteries, potassium‐ion batteries, dual ion batteries, electrochemical capacitors, and others. Additionally, carbon‐based electrocatalysts are also studied in hydrogen evolution reaction and carbon dioxide reduction reaction. However, there are still many challenges in the design and preparation of electrode and electrocatalytic materials. The research related to carbon materials for energy storage and conversion is extremely active, and this has motivated us to contribute with a roadmap on 'Carbon Materials in Energy Storage and Conversion'. [ABSTRACT FROM AUTHOR]

In this study, we explore the effect of carbon support on the performance of anodic electrodes for polymer electrolyte membrane fuel cells (PEMFCs). Pt−Ru catalysts supported on different carbon materials were synthesized by wet impregnation method and characterized by means of Raman, XRD, TEM, and N2 adsorption analysis. The electrocatalytic activity of the prepared catalysts was studied during hydrogen oxidation reaction experiments (HOR) as well as during the operation of a fuel cell using pure H2, and H2‐carbon monoxide anode feeding. The results show that the crystalline phase and the point of zero charge (pzc) of the carbon supports play an important role in the metal particle size and consequently in the catalyst electrocatalytic activity. Carbon supports with amorphous phase and high values of pzc, result in catalysts with large metal particle size leading to low electrocatalytic activity. On the other hand, using graphene derivative or carbon nanotubes (CNT) in different catalysts generates smaller metal particle size which results in higher electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Mechanical properties of graphene prepared by chemical vapour deposition (CVD) are not easily comparable to the properties of nearly perfect graphene prepared by mechanical cleavage. In this work, we attempt to investigate the mechanical performance of CVD graphene (simply supported or embedded in polymer matrix), transferred by two different techniques, under uniaxial loading with simultaneous in situ monitoring by Raman microspectroscopy. The level of charge transfer doping and strain is assessed using the vector analysis modified for uniaxial strain. The strain distribution across the samples varies significantly, owing to the growth and transfer process, which induces wrinkles and faults in the CVD graphene. In simply supported specimens, the stress transfer efficiency is generally very low and the changes in Raman spectra are dominated by variations in the charge transfer originating from the realignment of the domains on the substrate upon the application of strain. In contrast, samples covered with an additional polymer layer exhibit an improved stress transfer efficiency, and the alterations of charge doping levels are negligible. In fully embedded specimens, the variations in stress transfer efficiencies are caused by the size of the effective graphene domains defined by cracks, folds and/or wrinkles. [ABSTRACT FROM AUTHOR]

Keywords: Aspergillus niger; aerogels; ionic liquid; multi-functionality; VOCs EN Aspergillus niger aerogels ionic liquid multi-functionality VOCs 1 1 1 12/11/22 20221201 NES 221201 B Graphene-based aerogels b with an ionic liquid (IL) additive have been found to show remarkable anti-fungal activity, preventing the aerogel contamination with Aspergillus niger. These combined anti-fungal and VOC absorption properties are prerequisites for bringing preventive conservation to a higher level. When exposed to a volatile organic compound (VOC) saturated microenvironment, this aerogel was highly suitable for the absorption of acetaldehyde, formic acid, acetic acid, and formaldehyde. [Extracted from the article]

Front Cover: Effect of Carbon Support on the Electrocatalytic Properties of Pt-Ru Catalysts (ChemElectroChem 19/2019) Keywords: PEM fuel cells; Pt-Ru catalysts; graphene; biochar; carbon black; carbon nanotubes PEM fuel cells, Pt-Ru catalysts, graphene, biochar, carbon black, carbon nanotubes. [Extracted from the article]