Soft+Nanomaterials+Lab
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Chemical Scissors Snip 2D Transition Metal Dichalcogenides into Nanoribbon
New ‘nanoribbon’ catalyst should slash cost of hydrogen production for clean fuels
Researchers have identified a potential catalyst alternative – and an innovative way to produce them using chemical ‘scissors’ – that could make hydrogen production more economical.
The research team led by Professor Sang Ouk Kim at the Department of Materials Science and Engineering published their work in Nature Communications.
Hydrogen is likely to play a key role in the clean transition away from fossil fuels and other processes that produce greenhouse gas emissions. There is a raft of transportation sectors such as long-haul shipping and aviation that are difficult to electrify and so will require cleanly produced hydrogen as a fuel or as a feedstock for other carbon-neutral synthetic fuels. Likewise, fertilizer production and the steel sector are unlikely to be “de-carbonized” without cheap and clean hydrogen.
The problem is that the cheapest methods by far of producing hydrogen gas is currently from natural gas, a process that itself produces the greenhouse gas carbon dioxide–which defeats the purpose.
Alternative techniques of hydrogen production, such as electrolysis using an electric current between two electrodes plunged into water to overcome the chemical bonds holding water together, thereby splitting it into its constituent elements, oxygen and hydrogen are very well established. But one of the factors contributing to the high cost, beyond being extremely energy-intensive, is the need for the very expensive precious and relatively rare metal platinum. The platinum is used as a catalyst–a substance that kicks off or speeds up a chemical reaction–in the hydrogen production process.
As a result, researchers have long been on the hunt for a substitution for platinum -- another catalyst that is abundant in the earth and thus much cheaper.
Transition metal dichalcogenides, or TMDs, in a nanomaterial form, have for some time been considered a good candidate as a catalyst replacement for platinum. These are substances composed of one atom of a transition metal (the elements in the middle part of the periodic table) and two atoms of a chalcogen element (the elements in the third-to-last column in the periodic table, specifically sulfur, selenium and tellurium).
What makes TMDs a good bet as a platinum replacement is not just that they are much more abundant, but also their electrons are structured in a way that gives the electrodes a boost.
In addition, a TMD that is a nanomaterial is essentially a two-dimensional super-thin sheet only a few atoms thick, just like graphene. The ultrathin nature of a 2-D TMD nanosheet allows for a great many more TMD molecules to be exposed during the catalysis process than would be the case in a block of the stuff, thus kicking off and speeding up the hydrogen-making chemical reaction that much more.
However, even here the TMD molecules are only reactive at the four edges of a nanosheet. In the flat interior, not much is going on. In order to increase the chemical reaction rate in the production of hydrogen, the nanosheet would need to be cut into very thin – almost one-dimensional strips, thereby creating many edges.
In response, the research team developed what are in essence a pair of chemical scissors that can snip TMD into tiny strips.
“Up to now, the only substances that anyone has been able to turn into these ‘nano-ribbons’ are graphene and phosphorene,” said Sang Professor Kim, one of the researchers involved in devising the process.
“But they’re both made up of just one element, so it’s pretty straightforward. Figuring out how to do it for TMD, which is made of two elements was going to be much harder.”
The ‘scissors’ involve a two-step process involving first inserting lithium ions into the layered structure of the TMD sheets, and then using ultrasound to cause a spontaneous ‘unzipping’ in straight lines.
“It works sort of like how when you split a plank of plywood: it breaks easily in one direction along the grain,” Professor Kim continued. “It’s actually really simple.”
The researchers then tried it with various types of TMDs, including those made of molybdenum, selenium, sulfur, tellurium and tungsten. All worked just as well, with a catalytic efficiency as effective as platinum’s.
Because of the simplicity of the procedure, this method should be able to be used not just in the large-scale production of TMD nanoribbons, but also to make similar nanoribbons from other multi-elemental 2D materials for purposes beyond just hydrogen production.
-ProfileProfessor Sang Ouk KimSoft Nanomaterials Laboratory (http://snml.kaist.ac.kr)Department of Materials Science and EngineeringKAIST
2020.10.29 View 6850 -
The 10th KINC Fusion Research Awardees
The KAIST Institute for NanoCentury (KINC) recognized three distinguished researchers whose convergence studies made significant impacts. The KINC presented the 10th KINC Fusion Research Awards during a ceremony that took place at KAIST’s main campus in Daejeon on May 19.
This year’s ‘best’ convergence research award went to a joint research group led by Professor Hee Tak Kim from the Department of Chemical and Biomolecular Engineering and Professor Sang Ouk Kim from the Department of Materials Science and Engineering. Their research, featured in the December 27 issue of Advanced Materials as a front cover article last year, introduced the world’s first high-energy efficiency, membraneless, flowless, zinc-bromine battery. This study, in which research professor Gyoung Hwa Jeong, postdoctoral researcher Yearin Byun, and PhD candidate Ju-Hyuck Lee took part as co-lead authors, is deemed as an example of a best practice in convergence research in which two groups’ respective expertise in the fields of carbon materials and electrochemical analysis created a synergistic effect.
Professor Bumjoon Kim from the Department of Chemical and Biomolecular Engineering was also recognized for having published the most interdisciplinary research papers on polymer electronics and nanomaterials at home and abroad.
Professor Hee-Tae Jung, the Director of KINC and the host of the KINC Fusion Research Awards, said, “The KINC is happy to announce the 10th awardees in nano-fusion research this year. Since convergence is crucial for making revolutionary changes, the importance of convergence studies should be recognized. Our institute will spare no effort to create a research environment suitable for convergence studies, which will be crucial for making a significant difference.”
The KINC was established in June 2006 under the KAIST Institute with the mission of facilitating convergence studies by tearing down boarders among departments and carrying out interdisciplinary joint research. Currently, the institute is comprised of approximately 90 professors from 13 departments. It aims to become a hub of university institutes for nano-fusion research.
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2020.05.19 View 11742 -
Professor Sang Ouk Kim Receives the POSCO Academic Award
Professor Sang Ouk Kim of KAIST’s Department of Materials Science and Engineering received the 2015 POSCO Academic Award. The award ceremony took place at the annual conference of the Korean Institute of Metals and Materials on April 23, 2015.
The POSCO Academic Award has been presented to the Institute's researchers and academics in recognition of their contributions to the advancement of metals and materials engineering in Korea.
Professor Kim is known for his pioneering work in manipulating the properties (work function, conductivity, surface energy, chemo-responsiveness, etc.) of carbon-based materials using double-element doping. Through his research, Professor Kim showed that carbon materials could be extremely useful in various areas including solar batteries and flexible devices. His work has been recognized and published in such journals as Advanced Materials, which invited him to write a review paper on his research in its 25th anniversary issue in 2014, along with world-renowned scholars including the Nobel laureate Alan Heeger.
Professor Kim has published a total of 143 Science Citation Index papers in journals like Nature, Science, Nature Materials, Nature Communications, Advanced Materials, Nano Letters, and Physical Review Letters. According to Scopus, a bibliographic database containing abstracts and citations for academic journal articles, he has been cited 6,456 times and has the h-index of 44, an index describing the scientific productivity and impact of a researcher.
2015.04.22 View 9451 -
Professor Sang Ouk Kim receives the 2014 Prime Minister Award for Nano Research
Professor Sang Ouk Kim
Sang Ouk Kim, a professor of Materials Science and Engineering at KAIST, received the 2014 Prime Minister Award from the Korean government for his nano research. The award ceremony, Nano Korea 2014, was held on July 2, 2014 at Coex in Seoul, Korea.
Professor Kim was recognized for his research on the control of various shapes of ultra-fine nano-structures using molecular assembly with ductile materials, such as polymers and carbon nano materials, and for his contribution to the growth of the nano field in Korea.
He developed a new molecular assembly control technology, for the first time in the world, which produced large-scale, ultra-fine nanopatterns through controlling the molecular arrangement of block copolymers. Using this technology, he further created a new semiconductor nanotechnology to reinforce the existing lithographic process of semiconductor manufacturing.
In addition, Professor Kim has focused on making a new type of three-dimensional carbon nano-materials by assembling carbon nanotubes or graphene at the molecular level. Developing a new process to produce nano-materials through the chemical doping process of carbon materials, which can be widely applied to solar cells or energy devices, is one of his research interests as well.
Professor Kim has published a total of 124 papers in international journals, such as Nature, Science, Nature Materials, Nature Communications, Advanced Materials, and Nano Letters. He was recently invited by Advanced Materials to contribute a review article for its 25th anniversary issue.
Professor Kim received both the KAIST Academic Award and the 13th Young Scientist Award of Korea in 2010. Since March 2014, he has served as one of the chair professors of KAIST.
Most recently, he was selected as the Scientist of the Month in June 2014 by the Ministry of Science, ICT and Future Planning, Republic of Korea, and the National Research Foundation of Korea.
2014.07.08 View 8697 -
Professor Sang Ouk Kim Receives the "Scientist of the Month Award" from the Korean Government
Professor Sang Ouk Kim of the Department of Materials Science and Engineering, KAIST, received the Scientist of the Month Award in June 2014 for his development of a fundamental technology that allows free control of the properties of carbon-based materials.
Since June 1997, the Korean government has awarded monthly one scientist working in industry, universities, or research institutions to recognize his or her research achievements, as well as to promote science and technology.
Professor Kim implemented a technique known as doping, which has been used in ordinary semiconductor processes, to demonstrate the physical properties of carbon-based materials. Carbon nanotubes, graphene, and other carbon materials have superior mechanical and electrical properties and are regarded as next-generation materials. However, difficulty in controlling their qualities has made applications in various devices unfavorable. The doping technique in semiconductor production is to artificially introduce impurities into an extremely pure semiconductor for the purpose of modulating its electrical properties.
Profess Kim doped elements like nitrogen and boron to enable minute control of the physical properties of carbon-based materials and applied the technique to development of organic solar cells, organic light-emitting devices, and flexible memory. He also increased the application range by using a self-assembly method to change freely the structure of carbon-based materials.
Professor Kim has published 53 papers in renowned journals such as Advanced Materials and Nanoletters. He was rewarded further by being invited to write a review paper for the 25th anniversary special edition for Advanced Materials.
2014.06.19 View 9296 -
Professor Sang-Ouk Kim's Research on Carbon Materials Featured in a Philippines Science News
The subject article said that Professor Sang-Ouk Kim of Materials Science Engineering at KAIST “developed a technique to change the nature of the next-generation carbon-based materials. His research has expanded the possibility of carbon-based materials to be used in clothes.”
For details, please refer to the article below:
Centrio Times, June 10, 2014
KAIST scientist develops color changing carbon materials that can be used in clothes
http://www.centriotimes.com/2014/06/kaist-scientist-develops-color-changing-carbon-materials-can-used-clothes.html.
2014.06.15 View 7439 -
Professor Sang-Ouk Kim Publishes Review Article in the Journal of "Nature Materials"
Nature Materials, a
peer-reviewed scientific journal published by Nature Publishing Group, covers a
range of topics within materials science from materials engineering and
structural materials. The
journal invited Professor Sang-Ouk Kim of Materials Science and Engineering at
KAIST to contribute to the April issue of 2014. Professor Kim,
together with his doctoral student, Ju-Young Kim, wrote a review article in the
“News and Views” section of the journal, which was entitled “Liquid Crystals:
Electric Fields Line Up Graphene Oxide.” The
News and Views is a peer-reviewed section where an academic authority in a particular
field reviews and evaluates papers published in the journal. In
the article, Professor Kim reviewed a paper written by Jang-Kun Song et al. and
highlighted important research outcomes such as the efficient electric field switching
of graphene oxide (GO) liquid-crystals in low-concentration dispersions and the
demonstration of a prototype of a GO liquid-crystal display. This technology
could lead the development of a flexible display. Professor
Kim is an eminent scholar who has reported for the first time in the world on
the solvent-based graphene oxide liquid crystals formation in 2011. For the article, please go to: http://www.kaist.ac.kr/_prog/download.php?filename=Nature_Materials_Professor_Sang-Ouk_Kim_Apr_2014.pdf
2014.03.26 View 8923 -
Professor Sang-Ouk Kim Interviewed with Arirang TV on April 15, 2013
Professor Sang-Ouk Kim from the Department of Materials Science and Engineering made an appearance on April 15, 2013 at a morning show called “Korea Today” on Arirang TV, an English-language network based in Seoul, South Korea.
Professor Kim introduced his research on the development of flexible semiconductor technology. If commercialized, Professor Kim added, the technology would expedite the common use of wearable computers including mobile devices as well as the development of bio-medical implanted and wireless telemetry bio-devices. To play the video, please click the link below (00:25:00): http://www.arirang.co.kr/Player/TV_Vod.asp?HL=X&code=VOD&vSeq=68872
2013.04.30 View 8455 -
From Pencil Lead to Batteries: the Unlimited Transformation of Carbon
Those materials, like lead or diamond, made completely up of Carbon are being used in numerous ways as materials or parts. Especially with the discovery of carbon nanotubes, graphemes, and other carbon based materials in nanoscale, the carbon based materials are receiving a lot of interest in both fields of research and industry.
The carbon nanotubes and graphemes are considered as the ‘dream material’ and have a structure of a cross section of a bee hive. Such structure allows the material to have strength higher than that of a diamond and still be able to bend, be transparent and also conduct electricity. However the problem up till now was that these carbon structures appeared in layers and in bunches and were therefore hard to separate to individual layers or tubes.
Professor Kim Sang Wook’s research team developed the technology that can assemble the grapheme and carbon nanotubes in a three dimensional manner.
The team was able to assemble the grapheme ad carbon nanotubes in an entirely new three dimensional structure. In addition, the team was able to efficiently extract single layered grapheme from cheap pencil lead.
Professor Kim is scheduled to give a guest lecture in the “Materials Research Society” in San Francisco and the paper was published in ‘Advanced Functional Materials’ magazine as an ‘Invited Feature Article’.
2011.05.11 View 10133 -
Dong Ah Newspaper Publish '100 Koreans who will Represent Korea in 10 years'
The 2011 list of ‘100 Koreans who will Represent Korea in 10 years’ published by Dong Ah Newspaper includes people of varying ages, vocation, and gender.
In terms of University Professors, five professors from each of KAIST and SNU (Seoul National University) were selected. Especially Professor Charles Ahn received the most votes due to his world class talent, potential, and dedication.
Professor Kim Sang Wook of the Department of Materials Science and Engineering is the world leading expert in the field of ‘Atom Construction Nanotechnology’ which deals with using macromolecules, carbon nanotubes, and grapheme to form various structures. His work on ‘low cost, large area nano patterning technology’ is expected to overcome the limits of nano treatment processes and its application in semi-conductors or displays carries great promise.
Professor Kim Eun Sung of the Department of Physics discovered a new quantum behavior, supersolidity, in a low temperature, solid Helium for the first time in the world and is the leading scientist that leads the mechanics behind such a phenomenon. Professor Kim is leading the field of supersolidity through his works on hidden phase in a low temperature solid Helium, the understanding the role of crystalline faults in the supersolidity phenomenon, and the destruction of the supersolid’s macromolecular phenomenon through spinning solids.
Professor Charles Ahn of the Graduate School of Innovation and Technology Management has been working as the developer of the V3 series (an anti-computer virus Vaccine Program) since 1988. He established the ‘Charles Ahn Research Center’ in 1995 and his solid and practical management style won him rave reviews. Professor Ahn was appointed as the Professor of the Graduate School of Innovation and Technology Management and has been teaching entrepreneurial perspective and Technology Management.
Professor Lee Sang Yeop of the Department of Biology and Chemical Engineering developed world’s most efficient production method of succinic acid, developed high efficiency, tailored, culture for the production of key amino acids, Valine and Threonine, developed the production culture off bio-buthanol which is superior to bio-ethanol, and is widely known as one of the leaders in the field of metabolic engineering.
Professor Jeong Ha Woong of the Department of Physics is being regarded as world leader in the field of Complex System Network Sciences. He implemented Statistical Physics to Complex Systems and also used the concept of ‘Networks’ and published 80 papers, including 5 which were published in Nature Magazine.
2011.04.30 View 12480
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Prof. Sang-Ouk Kim Featured on the Cover of Emerging Investigator Special Issue
KAIST Prof. Sang-Ouk Kim of the Department of Materials Science and Engineering was featured on the cover of the Emerging Investigator Special Issue published by Britain"s Royal Society of Chemistry on June 21, university authorities said on Monday (June 22).
The special issue shed spotlight on 18 up-and-coming scientists who have been selected through the recommendation and rigorous screening process of the editorial and advisory boards of the Royal Society of Chemistry. The 18 scientists consist of six from the American continent, 10 from Europe, one from Japan and one from Korea.
The journal introduced Prof. Kim"s paper, titled "Highly entangled carbon nanotube (CNT) scaffolds by self-organized aqueous droplets." Kim explained in the paper that the cellular CNT demonstrated high electrical conductivity and field-emission properties, which is potentially useful for various applications in electronics and energy storage devices.
2009.06.24 View 11996 -
KAIST Professor Unveils New Method of Manufacturing Complex Nano-wire
A KAIST research team led by Prof. Sang-Ouk Kim of the Department of Materials Science and Engineering has discovered a new nanowire manufacturing method, university sources said on Monday (May 11).
The KAIST researchers successfully demonstrated soft graphoepitaxy of block copolymer assembly as a facile, scalable nanolithography for highly ordered sub-30-nm scale features. Graphoepitaxy is a new technique that uses artificial surface relief structure to induce crystallographic orientation in thin films.
Various morphologies of hierarchical block copolymer assembly were achieved by means of disposable topographic confinement of photoresist pattern. Unlike usual graphoepitaxy, soft graphoepitaxy generates the functional nanostrutures of metal and semiconductor nanowire arrays without any trace of structure-directing topographic pattern.
The discovery was featured in the May 7 edition of Nano-Letters. Application has been made for the domestic patent of the new method.
The new method is expected to be advantageous for multi-layer overlay processing required for complex device architecture, the sources said.
2009.05.12 View 10026