Tuesday , November 24 2020

The construction of smart graphics can lead to renewable fuels

Carbon, oxygen and hydrogen. These are the three elements you would get if you chose carbon dioxide and water molecules. The same atoms are the building blocks of the compounds we use as fuels, such as ethanol and methane gas. If it was possible to convert carbon dioxide and water into renewable fuels, it could be an alternative to the use of mineral oils and could help reduce carbon dioxide emissions in the atmosphere.

Jianwu Sun, Associate Professor at Linköping University, is studying a way to do this.

The first step is that researchers need to develop the material they intend to use. Researchers at Linköping University (LiU) have previously developed a world-class pioneering method for the production of silicon carbide, made up of silicon and carbon. The cubic shape has the ability to capture solar energy and create load carriers.

A subject with unique features
But that is not enough. The graph, one of the finest materials ever produced, now has the main role in the project. The material consists of a single layer of carbon atoms bonded to each other in a hexagonal chicken mesh pattern. The graph has a great ability to conduct electricity, a property that can be used to convert solar energy. It also has several unique features and people are conducting many surveys about possible chart applications.

In recent years, researchers have attempted to develop the chart development process on a surface to check the properties of the graph. A recently published article in Carbon magazine describes one of the latest developments.

– It is relatively easy to develop a layer of layers in cubic silicon carbide. But if you want to increase the graph in a series of even layers over one another in a larger area, it is a bigger challenge. We now show how it is possible to develop up to four chart levels above each other in a controlled manner, says Jianwu Sun at the Department of Physics, Chemistry and Biology (IFM).

Create even more stock
One of the difficulties with the multilayer grave is that the surface becomes uneven due to the fact that there are different layers in different parts. The end of a warehouse ends up as a small staircase at the nanoscale. For researchers who want large and uniform surfaces, these steps can be an obstacle. Particularly disturbing when stepping up, the ladder connects to the same place, like a wrong ladder, where many steps have been found together at an excessively high level. Now, scientists have found a way to get rid of the step-by-step phenomenon by increasing the graph at a carefully adjusted temperature and time. In addition, LiU researchers suggest that the approach allows control of the number of layers that the graph forms. This is the first step in the research program that aims to produce fuel from water and carbon dioxide.

In a closely related scientific article published in Nano Letters, researchers have explored the electronic properties of the multilayer tomb planted in cubic silicon carbide.

Can be used as a superconductor
– We have found that the multilayer graft has very promising electrical properties, allowing the material to be used as a non-conductive superconductor. This special feature only occurs when chart layers are organized in a specific way to each other, "says Jianwu Sun.

In previous studies, theoretical calculations predicted that these properties could occur when chart layers are organized in a specific way. The current study is the first experimental experiment that actually does. Extremely conductive materials are used in superconducting magnets, which are very powerful and are used in magnetic cameras for medical examinations and particle accelerators for research purposes. Many hope that superconductors can be used for energy-efficient power lines or high-speed floating trains in magnetic fields, among many others. The use today is limited by the fact that the existing superconductors do not operate at room temperature, but only at extremely low temperatures.

The studies were conducted with researchers at the MAX IV laboratory in Lund and were funded with support from the Swedish Research Council FORMAS, STINT, the ÅForsk Foundation and the Olle Engkvist Byggmästare Foundation.

Jianwu Sun, Associate Professor at the Department of Physics, Chemistry and Biology (IFM), Linköping University, [email protected], 013-28 27 03

(111), Yuchen Shi, Alexei A. Zacharov, Ivan G. Ivanov, G. Reza Yazdi, Valda Tzokovatsiyos, Michael Savvari, Rositsa Yakimova and Tziananou Soun, (2018). Carbon, 140, 533-542

The electronic structure platform and stratification separate the influence into a 4-layer burst Rhombohedral, Weimin Wang, Yuchen Shi, Alexei A. Zakharov, Mikael Syväjärvi, Rositsa Yakimova, Roger I. G. Uhrberg and Jianwu Sun, (2018), Nano Lett . 18 (9) 5862-5866

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