International Journal of Molecular Sciences

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16 pages, 4651 KiB

Open AccessArticle

Design of Novel Membranes for the Efficient Separation of Bee Alarm Pheromones in Portable Membrane Inlet Mass Spectrometric Systems

by Stevan Armaković, Daria Ilić and Boris Brkić

Int. J. Mol. Sci. 2024, 25(16), 8599; https://doi.org/10.3390/ijms25168599 - 7 Aug 2024

Viewed by 271

Abstract

Bee alarm pheromones are essential molecules that are present in beehives when some threats occur in the bee population. In this work, we have applied multilevel modeling techniques to understand molecular interactions between representative bee alarm pheromones and polymers such as polymethyl siloxane [...] Read more.

Bee alarm pheromones are essential molecules that are present in beehives when some threats occur in the bee population. In this work, we have applied multilevel modeling techniques to understand molecular interactions between representative bee alarm pheromones and polymers such as polymethyl siloxane (PDMS), polyethylene glycol (PEG), and their blend. This study aimed to check how these interactions can be manipulated to enable efficient separation of bee alarm pheromones in portable membrane inlet mass spectrometric (MIMS) systems using new membranes. The study involved the application of powerful computational atomistic methods based on a combination of modern semiempirical (GFN2-xTB), first principles (DFT), and force-field calculations. As a fundamental work material for the separation of molecules, we considered the PDMS polymer, a well-known sorbent material known to be applicable for light polar molecules. To improve its applicability as a sorbent material for heavier polar molecules, we considered two main factors—temperature and the addition of PEG polymer. Additional insights into molecular interactions were obtained by studying intrinsic reactive properties and noncovalent interactions between bee alarm pheromones and PDMS and PEG polymer chains. Full article

(This article belongs to the Special Issue Carbon–Multidisciplinary Investigations and Innovative Solutions)

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15 pages, 2848 KiB

Open AccessArticle

α-Fe₂O₃/, Co₃O₄/, and CoFe₂O₄/MWCNTs/Ionic Liquid Nanocomposites as High-Performance Electrocatalysts for the Electrocatalytic Hydrogen Evolution Reaction in a Neutral Medium

by José Ibarra, María Jesus Aguirre, Rodrigo del Río, Rodrigo Henriquez, Ricardo Faccio, Enrique A. Dalchiele, Roxana Arce and Galo Ramírez

Int. J. Mol. Sci. 2024, 25(13), 7043; https://doi.org/10.3390/ijms25137043 - 27 Jun 2024

Viewed by 1189

Abstract

Transition metal oxides are a great alternative to less expensive hydrogen evolution reaction (HER) catalysts. However, the lack of conductivity of these materials requires a conductor material to support them and improve the activity toward HER. On the other hand, carbon paste electrodes [...] Read more.

Transition metal oxides are a great alternative to less expensive hydrogen evolution reaction (HER) catalysts. However, the lack of conductivity of these materials requires a conductor material to support them and improve the activity toward HER. On the other hand, carbon paste electrodes result in a versatile and cheap electrode with good activity and conductivity in electrocatalytic hydrogen production, especially when the carbonaceous material is agglomerated with ionic liquids. In the present work, an electrode composed of multi-walled carbon nanotubes (MWCNTs) and cobalt ferrite oxide (CoFe₂O₄) was prepared. These compounds were included on an electrode agglomerated with the ionic liquid N-octylpyridinium hexafluorophosphate (IL) to obtain the modified CoFe₂O₄/MWCNTs/IL nanocomposite electrode. To evaluate the behavior of each metal of the bimetallic oxide, this compound was compared to the behavior of MWCNTs/IL where a single monometallic iron or cobalt oxides were included (i.e., α-Fe₂O₃/MWCNTs/IL and Co₃O₄/MWCNTs/IL). The synthesis of the oxides has been characterized by X-ray diffraction (XRD), RAMAN spectroscopy, and field emission scanning electronic microscopy (FE-SEM), corroborating the nanometric character and the structure of the compounds. The CoFe₂O₄/MWCNTs/IL nanocomposite system presents excellent electrocatalytic activity toward HER with an onset potential of −270 mV vs. RHE, evidencing an increase in activity compared to monometallic oxides and exhibiting onset potentials of −530 mV and −540 mV for α-Fe₂O₃/MWCNTs/IL and Co₃O₄/MWCNTs/IL, respectively. Finally, the system studied presents excellent stability during the 5 h of electrolysis, producing 132 μmol cm⁻² h⁻¹ of hydrogen gas. Full article

(This article belongs to the Special Issue Carbon–Multidisciplinary Investigations and Innovative Solutions)

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12 pages, 3039 KiB

Open AccessArticle

Adhesion States Greatly Affect Cellular Susceptibility to Graphene Oxide: Therapeutic Implications for Cancer Metastasis

by Keiko Morotomi-Yano, Shinya Hayami and Ken-ichi Yano

Int. J. Mol. Sci. 2024, 25(3), 1927; https://doi.org/10.3390/ijms25031927 - 5 Feb 2024

Cited by 1 | Viewed by 979

Abstract

Graphene oxide (GO) has received increasing attention in the life sciences because of its potential for various applications. Although GO is generally considered biocompatible, it can negatively impact cell physiology under some circumstances. Here, we demonstrate that the cytotoxicity of GO greatly varies [...] Read more.

Graphene oxide (GO) has received increasing attention in the life sciences because of its potential for various applications. Although GO is generally considered biocompatible, it can negatively impact cell physiology under some circumstances. Here, we demonstrate that the cytotoxicity of GO greatly varies depending on the cell adhesion states. Human HCT-116 cells in a non-adhered state were more susceptible to GO than those in an adherent state. Apoptosis was partially induced by GO in both adhered and non-adhered cells to a similar extent, suggesting that apoptosis induction does not account for the selective effects of GO on non-adhered cells. GO treatment rapidly decreased intracellular ATP levels in non-adhered cells but not in adhered ones, suggesting ATP depletion as the primary cause of GO-induced cell death. Concurrently, autophagy induction, a cellular response for energy homeostasis, was more evident in non-adhered cells than in adhered cells. Collectively, our observations provide novel insights into GO’s action with regard to cell adhesion states. Because the elimination of non-adhered cells is important in preventing cancer metastasis, the selective detrimental effects of GO on non-adhered cells suggest its therapeutic potential for use in cancer metastasis. Full article

(This article belongs to the Special Issue Carbon–Multidisciplinary Investigations and Innovative Solutions)

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13 pages, 9828 KiB

Open AccessArticle

Reduced Graphene Oxide Coating LiFePO₄ Composite Cathodes for Advanced Lithium-Ion Battery Applications

by Qingao Zhang, Yu Zhou, Yulong Tong, Yuting Chi, Ruhua Liu, Changkai Dai, Zhanqing Li, Zhenli Cui, Yaohua Liang and Yanli Tan

Int. J. Mol. Sci. 2023, 24(24), 17549; https://doi.org/10.3390/ijms242417549 - 16 Dec 2023

Cited by 9 | Viewed by 1450

Abstract

Recently, the application of LiFePO₄ (LFP) batteries in electric vehicles has attracted extensive attention from researchers. This work presents a composite of LFP particles trapped in reduced graphene oxide (rGO) nanosheets obtained through the high-temperature reduction strategy. The obtained LiFePO₄/rGO [...] Read more.

Recently, the application of LiFePO₄ (LFP) batteries in electric vehicles has attracted extensive attention from researchers. This work presents a composite of LFP particles trapped in reduced graphene oxide (rGO) nanosheets obtained through the high-temperature reduction strategy. The obtained LiFePO₄/rGO composites indicate spherical morphology and uniform particles. As to the structure mode of the composite, LFP distributes in the interlayer structure of rGO, and the rGO evenly covers the surface of the particles. The LFP/rGO cathodes demonstrate a reversible specific capacity of 165 mA h g⁻¹ and high coulombic efficiency at 0.2 C, excellent rate capacity (up to 10 C), outstanding long-term cycling stability (98%) after 1000 cycles at 5 C. The combined high electron conductivity of the layered rGO coating and uniform LFP particles contribute to the remarkable electrochemical performance of the LFP/rGO composite. The unique LFP/rGO cathode provides a potential application in high-power lithium-ion batteries. Full article

(This article belongs to the Special Issue Carbon–Multidisciplinary Investigations and Innovative Solutions)

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9 pages, 3264 KiB

Open AccessCommunication

Graphdiyne and Nitrogen-Doped Graphdiyne Nanotubes as Highly Efficient Electrocatalysts for Oxygen Reduction Reaction

by Tongchang Liu, Xinmeng Hao, Jiaqi Liu, Pengfei Zhang, Jiaming Chang, Hong Shang and Xuanhe Liu

Int. J. Mol. Sci. 2023, 24(23), 16813; https://doi.org/10.3390/ijms242316813 - 27 Nov 2023

Cited by 1 | Viewed by 1074

Abstract

Electrocatalysts with high efficiency and low cost are always urgently needed for oxygen reduction reaction (ORR). As a new carbon allotrope, graphdiyne (GDY) has received much attention due to its unique chemical structure containing sp- and sp²-hybridized carbons, and intrinsic electrochemical [...] Read more.

Electrocatalysts with high efficiency and low cost are always urgently needed for oxygen reduction reaction (ORR). As a new carbon allotrope, graphdiyne (GDY) has received much attention due to its unique chemical structure containing sp- and sp²-hybridized carbons, and intrinsic electrochemical activity ascribed to its inherent conductivity. Herein, we prepared two graphdiyne materials named GDY nanotube and nitrogen-doped GDY (NGDY) nanotube via cross-coupling reactions on the surface of Cu nanowires. As metal-free catalysts, their electrocatalytic activities for ORR were demonstrated. The results showed that the NGDY nanotube presents more excellent electrochemical performance than that of the GDY nanotube, including more positive potential and faster kinetics and charge transfer process. The improvement can be ascribed to the greater number of structural electrocatalytic active sites from nitrogen atoms as well as the hollow nanotube morphology, which is beneficial to the adsorption of oxygen and acceleration of the catalytic reaction. This work helps develop high-quality graphdiyne-based electrocatalysts with well-defined chemical structures and morphologies for various electrochemical reactions. Full article

(This article belongs to the Special Issue Carbon–Multidisciplinary Investigations and Innovative Solutions)

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20 pages, 4517 KiB

Open AccessArticle

The Role of Hydrogen Incorporation into Amorphous Carbon Films in the Change of the Secondary Electron Yield

by Nenad Bundaleski, Carolina F. Adame, Eduardo Alves, Nuno P. Barradas, Maria F. Cerqueira, Jonas Deuermeier, Yorick Delaup, Ana M. Ferraria, Isabel M. M. Ferreira, Holger Neupert, Marcel Himmerlich, Ana Maria M. B. do Rego, Martino Rimoldi, Orlando M. N. D. Teodoro, Mikhail Vasilevskiy and Pedro Costa Pinto

Int. J. Mol. Sci. 2023, 24(16), 12999; https://doi.org/10.3390/ijms241612999 - 20 Aug 2023

Viewed by 1316

Abstract

Over the last few years, there has been increasing interest in the use of amorphous carbon thin films with low secondary electron yield (SEY) to mitigate electron multipacting in particle accelerators and RF devices. Previous works found that the SEY increases with the [...] Read more.

Over the last few years, there has been increasing interest in the use of amorphous carbon thin films with low secondary electron yield (SEY) to mitigate electron multipacting in particle accelerators and RF devices. Previous works found that the SEY increases with the amount of incorporated hydrogen and correlates with the Tauc gap. In this work, we analyse films produced by magnetron sputtering with different contents of hydrogen and deuterium incorporated via the target poisoning and sputtering of C_xD_y molecules. XPS was implemented to estimate the phase composition of the films. The maximal SEY was found to decrease linearly with the fraction of the graphitic phase in the films. These results are supported by Raman scattering and UPS measurements. The graphitic phase decreases almost linearly for hydrogen and deuterium concentrations between 12% and 46% (at.), but abruptly decreases when the concentration reaches 53%. This vanishing of the graphitic phase is accompanied by a strong increase of SEY and the Tauc gap. These results suggest that the SEY is not dictated directly by the concentration of H/D, but by the fraction of the graphitic phase in the film. The results are supported by an original model used to calculate the SEY of films consisting of a mixture of graphitic and polymeric phases. Full article

(This article belongs to the Special Issue Carbon–Multidisciplinary Investigations and Innovative Solutions)

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14 pages, 1876 KiB

Open AccessArticle

Carbon Dioxide Capture by Adsorption in a Model Hydroxy-Modified Graphene Pore

by Paige Freyre, Emalee St. Pierre and Thomas Rybolt

Int. J. Mol. Sci. 2023, 24(14), 11452; https://doi.org/10.3390/ijms241411452 - 14 Jul 2023

Cited by 1 | Viewed by 1291

Abstract

Concerns regarding the environmental impact of increasing levels of anthropogenic carbon dioxide have led to a variety of studies examining solid surfaces for their ability to trap this greenhouse gas (GHG). Atmospheric or post-combustion carbon capture requires an efficient separation of carbon dioxide [...] Read more.

Concerns regarding the environmental impact of increasing levels of anthropogenic carbon dioxide have led to a variety of studies examining solid surfaces for their ability to trap this greenhouse gas (GHG). Atmospheric or post-combustion carbon capture requires an efficient separation of carbon dioxide and nitrogen gas. We used the molecular mechanics MM3 parameter set (previously shown to provide good estimates of molecule–surface binding energies) to calculate theoretical surface binding energies for carbon dioxide ∆E(CO₂) and nitrogen ∆E(N₂). For efficient separation, differentiation of these two gas-surface adsorption energies is required. Examined structures based on graphene, carbon slit width pore, and carbon nanotube gave ∆E(CO₂) to ∆E(N₂) ratios of 1.7, 1.8, and 1.9, respectively. To enhance the CO₂ adsorption, we developed a model graphene surface pore lined with four hydroxy groups whose orientation allowed them to form hydrogen bonds with the oxygens in CO₂. Both the single-layer and double-layer versions of this pore gave significant enhancement in the ability to trap CO₂ preferentially to N₂. The two-layer version of this pore gave ∆E(CO₂) = 73 and ∆E(N₂) = 6.8 kJ/mol. The one- and two-layer versions of this novel pore averaged a ∆E(CO₂) to ∆E(N₂) ratio of 12. Full article

(This article belongs to the Special Issue Carbon–Multidisciplinary Investigations and Innovative Solutions)

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Review

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19 pages, 1424 KiB

Open AccessReview

Carbon Dots—Types, Obtaining and Application in Biotechnology and Food Technology

by Joanna Szczepankowska, Gohar Khachatryan, Karen Khachatryan and Magdalena Krystyjan

Int. J. Mol. Sci. 2023, 24(19), 14984; https://doi.org/10.3390/ijms241914984 - 7 Oct 2023

Cited by 4 | Viewed by 3534

Abstract

Materials with a “nano” structure are increasingly used in medicine and biotechnology as drug delivery systems, bioimaging agents or biosensors in the monitoring of toxic substances, heavy metals and environmental variations. Furthermore, in the food industry, they have found applications as detectors of [...] Read more.

Materials with a “nano” structure are increasingly used in medicine and biotechnology as drug delivery systems, bioimaging agents or biosensors in the monitoring of toxic substances, heavy metals and environmental variations. Furthermore, in the food industry, they have found applications as detectors of food adulteration, microbial contamination and even in packaging for monitoring product freshness. Carbon dots (CDs) as materials with broad as well as unprecedented possibilities could revolutionize the economy, if only their synthesis was based on low-cost natural sources. So far, a number of studies point to the positive possibilities of obtaining CDs from natural sources. This review describes the types of carbon dots and the most important methods of obtaining them. It also focuses on presenting the potential application of carbon dots in biotechnology and food technology. Full article

(This article belongs to the Special Issue Carbon–Multidisciplinary Investigations and Innovative Solutions)

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