Soft drink by-products could reduce global w…

Soft drink by-products could reduce global warming

Professor of Chemistry Craig Teague and his students have discovered that the by-products of soft drinks could help reduce global warming.

A Cornell College team of researchers worked with other experts at the Oak Ridge National Laboratory in Tennessee on the idea starting in 2016, and their final conclusions were published in the journal article “Microporous and hollow carbon spheres derived from soft drinks: Promising CO2separation materials” in April of 2019. Their new research shows that the by-products of some soft drinks actually remove carbon dioxide, a gas known to warm the planet, from gas streams.

“In this research, we are looking at turning one waste material into something of value,” Teague said. “We looked at waste soft drinks–asking could we possibly find a way to make that waste useful by doing a simple process in the lab and taking the carbon out? That carbon, by the way we synthesized it, has tiny pores, which are able to capture carbon dioxide.”

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Electron beam strengthens recyclable nanocom…

Electron beam strengthens recyclable nanocomposite

Polymers reinforced with carbon fibers combine strength and low weight. They also boast significant green credentials as they are less resource-intensive during production and use, and they are readily recycled. While the mechanical properties of continuous-fiber laminates are sufficiently competitive for applications in aerospace and automobiles, composites reinforced with short carbon fibers could be attractive for fast-manufacture, and even 3-D printing for applications with more moderate strength requirements. As a result, there is keen interest in optimizing the mechanical properties of short-fiber reinforced thermoplastics to maximize on the potential of these materials. László Szabó and Kenji Takahashi and colleagues at Kanazawa University and Kanazawa Institute of Technology have now demonstrated that irradiating short carbon fiber thermoplastics with an electron beam can improve their mechanical properties.

The researchers limited their study to polymers that so that the resulting composite could be readily recycled and remolded into other forms. With environmentally friendly concerns in mind they focused the study on the biobased cellulose propionate for the composite matrix. Their study included investigation of the effects of electron beamirradiation on the strength for polymers functionalized with esters to increase crosslinking, and enhanced with carbon fibers, as well as different forms during irradiation (dumbbells and pellets) and long and short extrusion nozzles.

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Heated crystal flakes can be sewn into cloth…

Heated crystal flakes can be sewn into clothing for thermotherapy

Heated gloves, bracelets, and even rings are some of the potential applications of highly conductive MXene, a 2-D material made of alternating atomic layers of titanium and carbon. In a new study, researchers have fabricated MXene flakes, then electrostatically adhered the flakes to threads, and finally sewed the threads into ordinary fabrics that can be safely heated under a low voltage.

The researchers, led by Chong Min Koo, at the Korea Institute of Science and Technology and Korea University, and Cheolmin Park, at Yonsei University, have published a paper on the shape-adaptable MXene heater in a recent issue of ACS Nano.

In recent years, researchers have been investigating different materials to be used as flexible, wearable heaters. Although materials such as carbon nanotubes and graphene have excellent electrical and optical properties, it has been challenging to process them for use in applications.

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Organic electronics: a new semiconductor in the carbon-nitride family

Teams from Humboldt-Universität and the Helmholtz-Zentrum Berlin have explored a new material in the carbon-nitride family. Triazine-based graphitic carbon nitride (TGCN) is a semiconductor that should be highly suitable for applications in optoelectronics. Its structure is two-dimensional and reminiscent of graphene. Unlike graphene, however, the conductivity in the direction perpendicular to its 2D planes is 65 times higher than along the planes themselves.

Some organic materials might be able to be utilised similarly to silicon semiconductors in optoelectronics. Whether in solar cells, light-emitting diodes, or in transistors – what is important is the band gap, i.e. the difference in energy level between electrons in the valence band (bound state) and the conduction band (mobile state). Charge carriers can be raised from the valence band into the conduction band by means of light or an electrical voltage. This is the principle behind how all electronic components operate. Band gaps of one to two electron volts are ideal.

A team headed by chemist Dr. Michael J. Bojdys at Humboldt University Berlin recently synthesised a new organic semiconductor material in the carbon-nitride family. Triazine-based graphitic carbon nitride (or TGCN) consists of only carbon and nitrogen atoms, and can be grown as a brown film on a quartz substrate.The combination of C and N atoms form hexagonal honeycombs similar to graphene, which consists of pure carbon.Just as with graphene, the crystalline structure of TGCN is two-dimensional.With graphene, however, the planar conductivity is excellent, while its perpendicular conductivity is very poor. In TGCN it is exactly the opposite: the perpendicular conductivity is about 65 times greater than the planar conductivity. With a band gap of 1.7 electron volts, TGCN is a good candidate for applications in optoelectronics.

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Atomic engineering with electric irradiation

Atomic engineering with electric irradiation

Atomic engineering can selectively induce specific dynamics on single atoms followed by combined steps to form large-scale assemblies thereafter. In a new study now published in Science Advances, Cong Su and an international, interdisciplinary team of scientists in the departments of Materials Science, Electronics, Physics, Nanoscience and Optoelectronic technology; first surveyed the single-step dynamics of graphene dopants. They then developed a theory to describe the probabilities of configurational outcomes based on the momentum of a primary knock-on atom post-collision in an experimental setup. Su et al. showed that the predicted branching ratio of configurational transformation agreed well with the single-atom experiments. The results suggest a way to bias single-atom dynamics to an outcome of interest and will pave the road to design and scale-up atomic engineering using electron irradiation.

Controlling the exact atomic structure of materials is an ultimate form of atomic engineering. Atomic manipulation and atom-by-atom assembly can create functional structures that are synthetically difficult to realize by exactly positioning the atomic dopants to modify the properties of carbon nanotubes and graphene. For example, in quantum informatics, nitrogen (N) or phosphorous (P) dopants can be incorporated due to their nonzero nuclear spin. To successfully conduct experimental atomic engineering, scientists must (1) understand how desirable local configurational change can be induced to increase the speed and the success rate of control, and (2) scale up the basic unit processes into feasible structural assemblies containing 1 to 1000 atoms to produce the desired functionality.

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Pantry ingredients can help grow carbon nano…

Pantry ingredients can help grow carbon nanotubes

Baking soda, table salt, and detergent are surprisingly effective ingredients for cooking up carbon nanotubes, researchers at MIT have found.

In a study published this week in the journal Angewandte Chemie, the team reports that sodium-containing compounds found in common household ingredients are able to catalyze the growth of carbon nanotubes, or CNTs, at much lower temperatures than traditional catalysts require.

The researchers say that sodium may make it possible for carbon nanotubes to be grown on a host of lower-temperature materials, such as polymers, which normally melt under the high temperaturesneeded for traditional CNT growth.

“In aerospace composites, there are a lot of polymers that hold carbon fibers together, and now we may be able to directly grow CNTs on polymer materials, to make stronger, tougher, stiffer composites,” says Richard Li, the study’s lead author and a graduate student in MIT’s Department of Aeronautics and Astronautics. “Using sodium as a catalyst really unlocks the kinds of surfaces you can grow nanotubes on.”

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Adding a carbon atom transforms 2-D semicond…

Adding a carbon atom transforms 2-D semiconducting material

A technique that introduces carbon-hydrogen molecules into a single atomic layer of the semiconducting material tungsten disulfide dramatically changes the electronic properties of the material, according to Penn State researchers at Penn State who say they can create new types of components for energy-efficient photoelectric devices and electronic circuits with this material.

“We have successfully introduced the carbon species into the monolayer of the semiconducting material,” said Fu Zhang, doctoral student in materials science and engineering lead author of a paper published online today in Science Advances.

Prior to doping—adding carbon—the semiconductor, a transition metal dichalcogenide (TMD), was n-type—electron conducting. After substituting carbon atoms for sulfur atoms, the one-atom-thick material developed a bipolar effect, a p-type—hole—branch, and an n-type branch. This resulted in an ambipolar semiconductor.

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Electrode’s ‘hot edges’ co…

Electrode’s ‘hot edges’ convert carbon dioxide gas into fuels and chemicals

A team of scientists has created a bowl-shaped electrode with ‘hot edges’ which can efficiently convert CO2 from gas into carbon based fuels and chemicals, helping combat the climate change threat posed by atmospheric carbon dioxide.

The research team, from the University of Bath, Fudan University, Shanghai, and the Shanghai Institute of Pollution Control and Ecological Security, hopes the catalyst design will eventually allow the use of renewable electricity to convert CO2 into fuels without creating additional atmospheric carbon – essentially acting like an electrochemical ‘leaf’ to convert carbon dioxide into sugars.

Using this reaction, known as the reduction of carbon dioxide, has exciting potential but two major obstacles are poor conversion efficiency of the reaction and a lack of detailed knowledge about the exact reaction pathway.

This new electrode addresses these challenges with higher conversion efficiency and sensitive detection of molecules created along the reaction’s progress – thanks to its innovative shape and construction. The bowl shaped electrode works six times faster than standard planar – or flat – designs.

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