scholarly journals Multi-functional 2D hybrid aerogels for gas absorption applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charalampos Androulidakis ◽  
Maria Kotsidi ◽  
George Gorgolis ◽  
Christos Pavlou ◽  
Labrini Sygellou ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Hexagonal Boron Nitride ◽  
2D Materials ◽  
Cost Effective ◽  
Gas Absorption ◽  
Electrically Conductive ◽  
Thermal Actuators ◽  
Reduced Graphene ◽  
Hybrid Aerogels ◽  
Significant Attention

AbstractAerogels have attracted significant attention recently due to their ultra-light weight porous structure, mechanical robustness, high electrical conductivity, facile scalability and their use as gas and oil absorbers. Herein, we examine the multi-functional properties of hybrid aerogels consisting of reduced graphene oxide (rGO) integrated with hexagonal boron nitride (hBN) platelets. Using a freeze-drying approach, hybrid aerogels are fabricated by simple mixing with various volume fractions of hBN and rGO up to 0.5/0.5 ratio. The fabrication method is simple, cost effective, scalable and can be extended to other 2D materials combinations. The hybrid rGO/hBN aerogels (HAs) are mechanically robust and highly compressible with mechanical properties similar to those of the pure rGO aerogel. We show that the presence of hBN in the HAs enhances the gas absorption capacities of formaldehyde and water vapour up to ~ 7 and > 8 times, respectively, as compared to pure rGO aerogel. Moreover, the samples show good recoverability, making them highly efficient materials for gas absorption applications and for the protection of artefacts such as paintings in storage facilities. Finally, even in the presence of large quantity of insulating hBN, the HAs are electrically conductive, extending the potential application spectrum of the proposed hybrids to the field of electro-thermal actuators. The work proposed here paves the way for the design and production of novel 2D materials combinations with tailored multi-functionalities suited for a large variety of modern applications.

scholarly journals Facile sonochemical-assisted synthesis of orthorhombic phase black phosphorus/rGO hybrids for effective photothermal therapy

Nanophotonics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 3023-3034
Author(s):  
Weiyuan Liang ◽  
Dou Wang ◽  
Xiaohui Ren ◽  
Chenchen Ge ◽  
Hanyue Wang ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Orthorhombic Phase ◽  
Cost Effective ◽  
Black Phosphorus ◽  
Antitumor Effects ◽  
Covalent Bonds ◽  
Preparation Conditions ◽  
Reduced Graphene

AbstractTwo-dimensional black phosphorus (BP) has been demonstrated to be promising in photoelectronic devices, electrode materials, and biomedicine owing to its outstanding properties. However, the application of BP has been hindered by harsh preparation conditions, high costs, and easy degradation in ambient condition. Herein, we report a facile and cost-effective strategy for synthesis of orthorhombic phase BP and a kind of BP-reduced graphene oxide (BP/rGO) hybrids in which BP remains stable for more than 4 weeks ascribed to the formation of phosphorus-carbon covalent bonds between BP and rGO as well as the protection effect of the unique wrinkle morphology of rGO nanosheets. Surface modification BP/rGO hybrids (PEGylated BP/rGO) exhibit excellent photothermal performance with photothermal conversion efficiency as high as 57.79% at 808 nm. The BP/rGO hybrids exhibit enhanced antitumor effects both in vitro and in vivo, showing promising perspectives in biomedicine.

scholarly journals 2D-3D integration of hexagonal boron nitride and a high-κ dielectric for ultrafast graphene-based electro-absorption modulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hitesh Agarwal ◽  
Bernat Terrés ◽  
Lorenzo Orsini ◽  
Alberto Montanaro ◽  
Vito Sorianello ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hafnium Oxide ◽  
High Speed ◽  
Hexagonal Boron Nitride ◽  
Temperature Stability ◽  
Cost Effective ◽  
Fold Increase ◽  
Building Blocks ◽  
High Quality ◽  
New Device

AbstractElectro-absorption (EA) waveguide-coupled modulators are essential building blocks for on-chip optical communications. Compared to state-of-the-art silicon (Si) devices, graphene-based EA modulators promise smaller footprints, larger temperature stability, cost-effective integration and high speeds. However, combining high speed and large modulation efficiencies in a single graphene-based device has remained elusive so far. In this work, we overcome this fundamental trade-off by demonstrating the 2D-3D dielectric integration in a high-quality encapsulated graphene device. We integrated hafnium oxide (HfO2) and two-dimensional hexagonal boron nitride (hBN) within the insulating section of a double-layer (DL) graphene EA modulator. This combination of materials allows for a high-quality modulator device with high performances: a ~39 GHz bandwidth (BW) with a three-fold increase in modulation efficiency compared to previously reported high-speed modulators. This 2D-3D dielectric integration paves the way to a plethora of electronic and opto-electronic devices with enhanced performance and stability, while expanding the freedom for new device designs.

scholarly journals Chlorosulfuric acid-assisted production of functional 2D materials

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohsen Moazzami Gudarzi ◽  
Maryana Asaad ◽  
Boyang Mao ◽  
Gergo Pinter ◽  
Jianqiang Guo ◽  
...  
Keyword(s):  
Hexagonal Boron Nitride ◽  
2D Materials ◽  
Real Life ◽  
Large Area ◽  
Polar Solvents ◽  
Aspect Ratios ◽  
Two Dimensional Materials ◽  
Liquid Phase Exfoliation

AbstractThe use of two-dimensional materials in bulk functional applications requires the ability to fabricate defect-free 2D sheets with large aspect ratios. Despite huge research efforts, current bulk exfoliation methods require a compromise between the quality of the final flakes and their lateral size, restricting the effectiveness of the product. In this work, we describe an intercalation-assisted exfoliation route, which allows the production of high-quality graphene, hexagonal boron nitride, and molybdenum disulfide 2D sheets with average aspect ratios 30 times larger than that obtained via conventional liquid-phase exfoliation. The combination of chlorosulfuric acid intercalation with in situ pyrene sulfonate functionalisation produces a suspension of thin large-area flakes, which are stable in various polar solvents. The described method is simple and requires no special laboratory conditions. We demonstrate that these suspensions can be used for fabrication of laminates and coatings with electrical properties suitable for a number of real-life applications.

scholarly journals Elucidation of the Crystal Growth Characteristics of SnO2 Nanoaggregates Formed by Sequential Low-Temperature Sol-Gel Reaction and Freeze Drying

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1738
Author(s):  
Saeid Vafaei ◽  
Alexander Wolosz ◽  
Catlin Ethridge ◽  
Udo Schnupf ◽  
Nagisa Hattori ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Low Temperature ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Freeze Drying ◽  
Sno2 Nanoparticles ◽  
Sol Gel ◽  
Functional Materials ◽  
Cost Effective ◽  
High Concentration

SnO2 nanoparticles are regarded as attractive, functional materials because of their versatile applications. SnO2 nanoaggregates with single-nanometer-scale lumpy surfaces provide opportunities to enhance hetero-material interfacial areas, leading to the performance improvement of materials and devices. For the first time, we demonstrate that SnO2 nanoaggregates with oxygen vacancies can be produced by a simple, low-temperature sol-gel approach combined with freeze-drying. We characterize the initiation of the low-temperature crystal growth of the obtained SnO2 nanoaggregates using high-resolution transmission electron microscopy (HRTEM). The results indicate that Sn (II) hydroxide precursors are converted into submicrometer-scale nanoaggregates consisting of uniform SnO2 spherical nanocrystals (2~5 nm in size). As the sol-gel reaction time increases, further crystallization is observed through the neighboring particles in a confined part of the aggregates, while the specific surface areas of the SnO2 samples increase concomitantly. In addition, X-ray photoelectron spectroscopy (XPS) measurements suggest that Sn (II) ions exist in the SnO2 samples when the reactions are stopped after a short time or when a relatively high concentration of Sn (II) is involved in the corresponding sol-gel reactions. Understanding this low-temperature growth of 3D SnO2 will provide new avenues for developing and producing high-performance, photofunctional nanomaterials via a cost-effective and scalable method.

scholarly journals MoS2/h-BN/Graphene Heterostructure and Plasmonic Effect for Self-Powering Photodetector: A Review

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1672
Author(s):  
Umahwathy Sundararaju ◽  
Muhammad Aniq Shazni Mohammad Haniff ◽  
Pin Jern Ker ◽  
P. Susthitha Menon
Keyword(s):  
Flexible Electronics ◽  
Hexagonal Boron Nitride ◽  
2D Materials ◽  
Optical Power ◽  
Active Regions ◽  
Green Technology ◽  
Plasmonic Effect ◽  
Zero Bias ◽  
Electrical Signals ◽  
Self Powered

A photodetector converts optical signals to detectable electrical signals. Lately, self-powered photodetectors have been widely studied because of their advantages in device miniaturization and low power consumption, which make them preferable in various applications, especially those related to green technology and flexible electronics. Since self-powered photodetectors do not have an external power supply at zero bias, it is important to ensure that the built-in potential in the device produces a sufficiently thick depletion region that efficiently sweeps the carriers across the junction, resulting in detectable electrical signals even at very low-optical power signals. Therefore, two-dimensional (2D) materials are explored as an alternative to silicon-based active regions in the photodetector. In addition, plasmonic effects coupled with self-powered photodetectors will further enhance light absorption and scattering, which contribute to the improvement of the device’s photocurrent generation. Hence, this review focuses on the employment of 2D materials such as graphene and molybdenum disulfide (MoS2) with the insertion of hexagonal boron nitride (h-BN) and plasmonic nanoparticles. All these approaches have shown performance improvement of photodetectors for self-powering applications. A comprehensive analysis encompassing 2D material characterization, theoretical and numerical modelling, device physics, fabrication and characterization of photodetectors with graphene/MoS2 and graphene/h-BN/MoS2 heterostructures with plasmonic effect is presented with potential leads to new research opportunities.

scholarly journals Boron nitride nanoplatelets as two-dimensional thermal fillers in epoxy composites: new scenarios at very low filler loadings

2020 ◽  
Vol 40 (10) ◽  
pp. 859-867
Author(s):  
Yao Shi ◽  
Genlian Lin ◽  
Xi-Fei Ma ◽  
Xiao Huang ◽  
Jing Zhao ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Boron Nitride ◽  
Filler Content ◽  
Hexagonal Boron Nitride ◽  
Filler Loading ◽  
Epoxy Composites ◽  
General Phenomenon ◽  
Sudden Drop ◽  
Reduced Graphene ◽  
Thermal Conducting

AbstractHexagonal boron nitride (h-BN) nanoplatelets (0.6 μm in diameter and 100 nm in thickness) are introduced into epoxy resin to improve the polymer’s thermal conducting ability. As expected, the thermal conductivities (TCs) of the composites, especially the in-plane TCs, are significantly increased. The in-plane TC of the epoxy composites can reach 1.67 W/mK at only 0.53 wt% loading, indicating h-BN nanopletelets are very effective thermal fillers. However, after carefully studied the correlation of the TC improvement and filler content, a sudden drop of the TC around 0.53 wt% filler loading is observed. Such an unexpected decrease in TC has never been reported and is also found to be consistent with the Tg changes versus filler content. Similar trend is also observed in other 2-D nanofillers, such as graphene oxide, reduced graphene oxide, which may indicate it is a general phenomenon for 2-D nanofillers. SEM results suggest that such sudden drop in TC might be coming from the enrichment of these 2-D nanofillers in localized areas due to their tendency to form more ordered phase above certain concentrations.

scholarly journals Paper-based potentiometric sensing devices modified with chemically reduced graphene oxide (CRGO) for trace level determination of pholcodine (opiate derivative drug)

RSC Advances ◽  
2021 ◽  
Vol 11 (20) ◽  
pp. 12227-12234
Author(s):  
Hisham S. M. Abd-Rabboh ◽  
Abd El-Galil E. Amr ◽  
Elsayed A. Elsayed ◽  
Ahmed Y. A. Sayed ◽  
Ayman H. Kamel
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Cost Effective ◽  
Trace Level ◽  
Ion Sensing ◽  
Reduced Graphene ◽  
Chemically Reduced Graphene Oxide ◽  
Trace Level Determination ◽  
Analytical Device

Robust, reliable and cost-effective paper-based analytical device for potentiometric pholcodine (opiate derivative drug) ion sensing has been prepared and characterized.

Tuning the cationic ratio of Fe1CoxNiyP integrated on Vertically aligned reduced graphene oxide array via electroless plating as efficient self-supported bifunctional electrocatalyst for water splitting

2021 ◽  
pp. 1-33
Author(s):  
Kaiming Guo ◽  
Firdoz Shaik ◽  
Jine Yang ◽  
Bin Jiang
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Water Splitting ◽  
Electroless Plating ◽  
Cost Effective ◽  
Bifunctional Electrocatalyst ◽  
Reduced Graphene ◽  
Wide Ph Range ◽  
Vertically Aligned ◽  
Ph Range

Abstract Water splitting is considered as a potential sustainable and green technology for producing mass hydrogen and oxygen. A cost-effective self-supported stable electrocatalyst with excellent electrocatalytic performance in a wide pH range is greatly required for water splitting. This work reports on the synthesis and anchoring of Fe1CoxNiyP nanoparticles on vertically aligned reduced graphene oxide array (VrGO) via electroless plating. The catalytic activity of Fe1CoxNiyP nanoparticles is tuned finely by tailoring the cationic ratio of Co and Ni. Fe1Co2Ni1P/VrGO exhibits the lowest overpotential (58 and 110 mV) at 10 mA cm−2 and lowest tafel slope (31 and 33 mV dec−1) for hydrogen evolution reaction in 1.0 M KOH and 0.5 M H2SO4 respectively. Fe1Co1Ni2P/VrGO exhibits the lowest overpotential (173 mV) at 10 mA cm−2 with lowest tafel slope (47 mV dec-1) for oxygen evolution reaction. The enhanced performance of the electrocatalyst is attributed to improved electrical conductivity, synergistic effects and beneficial electronic states caused by the appropriate atomic ratio of Co and Ni in the bifunctional electrocatalyst. This study helps to explore the effect of variable cationic ratio in the cost-effective ternary iron group metal phosphides electrocatalysts to achieve enhanced electrocatalytic performance for water splitting in a wide pH range.

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