scholarly journals Edge-Hydrogenated Germanene by Electrochemical Decalcification-Exfoliation of CaGe2: Germanene-Enabled Vapor Sensor

2021 ◽  
Author(s):  
Evgeniya Kovalska ◽  
Nikolas Antonatos ◽  
Jan Luxa ◽  
Zdenek Sofer
Keyword(s):  
Gas Sensing ◽  
Chemical Properties ◽  
Single Step ◽  
Synthetic Methods ◽  
Aqueous Environment ◽  
Free Standing ◽  
New Approach ◽  
Vapor Sensing ◽  
Vapor Sensor ◽  
First Time

<p><a>Two-dimensional germanene has been recently explored for applications in sensing, catalysis, and energy storage. The potential of this material lies on its graphene-like optoelectronic and chemical properties. However, pure free-standing germanene cannot be found in nature and the synthetic methods are hindering the potentially fascinating properties of germanene. </a>Herein, <a>we report for the first time a single-step synthesis of few-layer germanene by electrochemical exfoliation in non-aqueous environment. As a result of simultaneous decalcification and intercalation of the electrolyte’s active ions, we achieved a low-level hydrogenation of germanene that occurs at the edges of the material. The obtained edge-hydrogenated germanene flakes have a lateral size of several micrometers which possess a cubic structure. We have pioneered the potential application of edge-hydrogenated germanene for vapor sensing and demonstrated its specific sensitivity to methanol and ethanol. We have shown a selective behavior of the germanene-based sensor that appears to increase the electrical resistance in the vapors where methanol prevails. We anticipate that these results can provide a new approach for emerging layered materials with the potential utility in advanced gas sensing.</a></p>

scholarly journals Edge-Hydrogenated Germanene by Electrochemical Decalcification-Exfoliation of CaGe2: Germanene-Enabled Vapor Sensor

2021 ◽  
Author(s):  
Evgeniya Kovalska ◽  
Nikolas Antonatos ◽  
Jan Luxa ◽  
Zdenek Sofer
Keyword(s):  
Gas Sensing ◽  
Chemical Properties ◽  
Single Step ◽  
Synthetic Methods ◽  
Aqueous Environment ◽  
Free Standing ◽  
New Approach ◽  
Vapor Sensing ◽  
Vapor Sensor ◽  
First Time

<p><a>Two-dimensional germanene has been recently explored for applications in sensing, catalysis, and energy storage. The potential of this material lies on its graphene-like optoelectronic and chemical properties. However, pure free-standing germanene cannot be found in nature and the synthetic methods are hindering the potentially fascinating properties of germanene. </a>Herein, <a>we report for the first time a single-step synthesis of few-layer germanene by electrochemical exfoliation in non-aqueous environment. As a result of simultaneous decalcification and intercalation of the electrolyte’s active ions, we achieved a low-level hydrogenation of germanene that occurs at the edges of the material. The obtained edge-hydrogenated germanene flakes have a lateral size of several micrometers which possess a cubic structure. We have pioneered the potential application of edge-hydrogenated germanene for vapor sensing and demonstrated its specific sensitivity to methanol and ethanol. We have shown a selective behavior of the germanene-based sensor that appears to increase the electrical resistance in the vapors where methanol prevails. We anticipate that these results can provide a new approach for emerging layered materials with the potential utility in advanced gas sensing.</a></p>

scholarly journals Broad scope gold(i)-catalysed polyenyne cyclisations for the formation of up to four carbon–carbon bonds

2017 ◽  
Vol 15 (10) ◽  
pp. 2163-2167 ◽  
Author(s):  
Zhouting Rong ◽  
Antonio M. Echavarren
Keyword(s):  
Single Step ◽  
Simultaneous Formation ◽  
Broad Scope ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds ◽  
First Time ◽  
High Stereoselectivity

The polycyclisation of polyeneynes catalyzed by gold(i) has been extended for the first time to the simultaneous formation of up to four carbon–carbon bonds, leading to steroid-like molecules with high stereoselectivity in a single step with low catalyst loadings.

scholarly journals Composite Poly(vinyl alcohol)-Based Nanofibers Embedding Differently-Shaped Gold Nanoparticles: Preparation and Characterization

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1604
Author(s):  
Andrea Dodero ◽  
Maila Castellano ◽  
Paola Lova ◽  
Massimo Ottonelli ◽  
Elisabetta Brunengo ◽  
...  
Keyword(s):  
Vinyl Alcohol ◽  
Ad Hoc ◽  
Chemical Reduction ◽  
Chemical Properties ◽  
Single Step ◽  
Gold Nanostructures ◽  
Poly Vinyl Alcohol ◽  
Spherical Nanoparticles ◽  
Potential Applications ◽  
New Perspective

Poly(vinyl alcohol) nanofibrous mats containing ad hoc synthesized gold nanostructures were prepared via a single-step electrospinning procedure and investigated as a novel composite platform with several potential applications. Specifically, the effect of differently shaped and sized gold nanostructures on the resulting mat physical-chemical properties was investigated. In detail, nearly spherical nanoparticles and nanorods were first synthesized through a chemical reduction of gold precursors in water by using (hexadecyl)trimethylammonium bromide as the stabilizing agent. These nanostructures were then dispersed in poly(vinyl alcohol) aqueous solutions to prepare nanofibrous mats, which were then stabilized via a humble thermal treatment able to enhance their thermal stability and water resistance. Remarkably, the nanostructure type was proven to influence the mesh morphology, with the small spherical nanoparticles and the large nanorods leading to thinner well defined or bigger defect-rich nanofibers, respectively. Finally, the good mechanical properties shown by the prepared composite mats suggest their ease of handleability thereby opening new perspective applications.

Binary MOF of iron and copper for treating ciprofloxacin contaminated waste water by integrated technique of adsorption and photocatalytic degradation

2021 ◽  
Author(s):  
Aditi Chatterjee ◽  
Amiya K Jana ◽  
Jayanta Kumar Basu
Keyword(s):  
Waste Water ◽  
Water Pollution ◽  
Photocatalytic Degradation ◽  
Metal Organic Framework ◽  
Single Step ◽  
New Approach ◽  
Metal Organic ◽  
Integrated Technique ◽  
Contaminated Waste ◽  
Control Water

Adsorption assisted photocatalysis is a new approach to control water pollution. A novel metal organic framework MIL 53(Fe-Cu) was formulated by a single step solvothermal route. The newly developed MOF...

scholarly journals ZnO/RGO Heterojunction Based near Room Temperature Alcohol SENSOR with Improved Efficiency

2021 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Sanghamitra Ghosal ◽  
Partha Bhattacharyya
Keyword(s):  
Active Sites ◽  
Room Temperature ◽  
Surface Engineering ◽  
Gas Sensing ◽  
Energy Band Diagram ◽  
Future Generation ◽  
High Yield ◽  
Synthesis Process ◽  
Ethanol Sensor ◽  
Vapor Sensing

The systematic optimization of surface engineering (dimensionality) indeed plays a crucial role in achieving efficient vapor-sensing performance. Among various semiconducting metal oxides, owing to some of its unique features and advantages, ZnO has attracted researchers on a global scale due to its application in various fields, including chemical sensors. The concomitant optimization of the surface attributes (varying different dimensions) of ZnO have become a sensation for the entire research community. Moreover, the small thickness and extremely large surface of exfoliated 2D nanosheets render the gas sensing material an ideal candidate for achieving strong coupling with different gas molecules. However, temperature is a crucial factor in the field of chemical sensing. Recently, graphene-based gas sensors have attracted attention due to their variety of structures, unique sensing performances and room temperature working conditions. In this work, a highly sensitive and fast responsive low temperature (60 °C)-based ethanol sensor, based on RGO/2D ZnO nanosheets hybrid structure, is reported. After detailed characterizations, the vapor sensing potentiality of this sensor was tested for the detection of ethanol. The ethanol sensor offered the response magnitude of 89% (100 ppm concentration) with response and recovery time of 12 s/29 s, respectively. Due to excessively high number of active sites for VOC interaction, with high yield synthesis process and appreciably high carrier mobility, this has paved the way for developing future generation, miniaturized and flexible (wearable) vapor sensor devices, meeting the multidimensional requirements for traditional and upcoming (health/medical sector) applications. The underlying mechanistic framework for vapor sensing, using this hybrid junction, is explained with the Energy Band Diagram.

scholarly journals Bimetallic Nanocrystals: Structure, Controllable Synthesis and Applications in Catalysis, Energy and Sensing

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1926
Author(s):  
Gaojie Li ◽  
Wenshuang Zhang ◽  
Na Luo ◽  
Zhenggang Xue ◽  
Qingmin Hu ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Chemical Properties ◽  
Research Progress ◽  
Synthesis Methods ◽  
Controlled Synthesis ◽  
Controllable Synthesis ◽  
Composition And Structure ◽  
Bimetallic Nanocrystals ◽  
Physical And Chemical ◽  
And Chemical Properties

In recent years, bimetallic nanocrystals have attracted great interest from many researchers. Bimetallic nanocrystals are expected to exhibit improved physical and chemical properties due to the synergistic effect between the two metals, not just a combination of two monometallic properties. More importantly, the properties of bimetallic nanocrystals are significantly affected by their morphology, structure, and atomic arrangement. Reasonable regulation of these parameters of nanocrystals can effectively control their properties and enhance their practicality in a given application. This review summarizes some recent research progress in the controlled synthesis of shape, composition and structure, as well as some important applications of bimetallic nanocrystals. We first give a brief introduction to the development of bimetals, followed by the architectural diversity of bimetallic nanocrystals. The most commonly used and typical synthesis methods are also summarized, and the possible morphologies under different conditions are also discussed. Finally, we discuss the composition-dependent and shape-dependent properties of bimetals in terms of highlighting applications such as catalysis, energy conversion, gas sensing and bio-detection applications.

scholarly journals New Synthetic Methods of Novel Nanoporous Polycondensates and Excellent Oxygen Permselectivity of Their Composite Membranes

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 859
Author(s):  
Yu Zang ◽  
Toshiki Aoki ◽  
Masahiro Teraguchi ◽  
Takashi Kaneko ◽  
Hongge Jia ◽  
...  
Keyword(s):  
Contact Angle ◽  
Upper Bound ◽  
Oxygen Permeability ◽  
Membrane Surface ◽  
Composite Membranes ◽  
Synthetic Methods ◽  
Preparation Methods ◽  
First Time

Two kinds of novel nanoporous polycondensates (sc(Rf)) have been synthesized by two new preparation methods consisting of polycondensation and highly selective photocyclicaromataization of 1/3 helical cis-cis polyphenylacetylenes with polymerizable groups. By the original methods, new well-defined sheet polymers having nanopores or nanospaces have been synthesized for the first time. Their composite membranes, containing small amounts (1.0 wt%) of sc(Rf), had ultrahigh oxygen permeability (Po2 > 1000 barrer), and their plots were beyond the Robeson’s upper bound line in the graph of oxygen permselectivity (α = Po2/PN2) versus Po2. Both α and Po2 values were enhanced by adding only small amounts (1.0 wt%) of sc(Rf). One of the sc(Rf)s synthesized on the base membrane surface showed the best performance, i.e., Po2 = 5300 barrer and α = 2.5. The membrane surface was effectively covered by sc(Rf), judging from the contact angle values. It is thought that nanopores and nanospaces created in and between sc(Rf) molecules played an important role for the enhancement of both α and Po2/PN2.

A multi-manned assembly line balancing problem with classified teams: a new approach

2016 ◽  
Vol 36 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Hamid Yilmaz ◽  
Mustafa Yilmaz
Keyword(s):  
Design Methodology ◽  
Assembly Line ◽  
Assembly Line Balancing ◽  
Line Balancing ◽  
Test Problems ◽  
New Approach ◽  
Content Type ◽  
Line Test ◽  
Assembly Line Balancing Problem ◽  
First Time

Purpose – Within team-oriented approaches, tasks are assigned to teams before being assigned to workstations as a reality of industry. So it becomes clear, which workers assemble which tasks. Design/methodology/approach – Team numbers of the assembly line can increase with the number of tasks, but at the same time, due to physical situations of the stations, there will be limitations of maximum working team numbers in a station. For this purpose, heuristic assembly line balancing (ALB) procedure is used and mathematical model is developed for the problem. Findings – Well-known assembly line test problems widely used in the literature are solved to indicate the effectiveness and applicability of the proposed approach in practice. Originality/value – This paper draws attention to ALB problem in which workers have been assigned to teams in advance due to the need for specialized skills or equipment on the line for the first time.

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