- A world record-breaking solar-to-chemical conversion efficiency of 1.1% has been achieved, revolutionizing the production of hydrogen peroxide. Hydrogen peroxide, a key chemical used in the semiconductor production process, is one of the top 100 industrial chemicals and an important raw material widely used in disinfection, oxidation, and pulp manufacturing. The global hydrogen peroxide market is expected to exceed 7 trillion won in 2024. However, it is predicted that stable supply of hydrogen peroxide will be difficult to achieve due to the recent worldwide covid quarantine measures and rapid increase in demand for semiconductor production. Moreover, the current production method of hydrogen peroxide is a thermochemical process (anthraquinone process), which uses palladium, an expensive rare metal, as a catalyst at high temperature and pressure. This process not only consumes a lot of energy, but also causes various environmental problems such as the risk of explosion and emission of greenhouse gases. Although many efforts have been made to produce hydrogen peroxide with low energy consumption and low carbon emission, it is challenging to overcome the threshold of commercialization due to extremely low productivity and efficiency. Hence, there is an urgent need to develop eco-friendly technologies that can solve the problems of existing thermochemical processes. The Korea Institute of Science and Technology (KIST, President Seok Jin Yoon) announced in last November that Dr. Jeehye Byun’s research team at the Center for Water Cycle Research and Dr. Dong Ki Lee’s research team at the Clean Energy Research Center developed a new technology that uses sunlight to produce hydrogen peroxide at an unprecedented high concentration, replacing the need for high-temperature and high-pressure energy. This technology is an example of replacing a thermochemical process with a photocatalytic process to produce key chemical raw materials without carbon emissions. The KIST research team designed the photocatalytic reaction solution as an organic solution based on the fact that anthraquinone organic molecules undergo repeated oxidation and reduction reactions in the existing thermochemical process to produce hydrogen peroxide. As a result, they discovered that the oxygen reduction ability of the photocatalyst was improved in the organic reaction solution, and hydrogen peroxide production was greatly increased. In addition, the research team identified for the first time that the organic reaction solution itself absorbs light and produces hydrogen peroxide through a photochemical reaction. The research team achieved the result of producing hydrogen peroxide at a concentration of 53,000 ppm (i.e., 5.3%) per unit time and per gram of photocatalyst by using sunlight when controlling the photocatalyst and reaction solution. This is an achievement that exceeds the hydrogen peroxide production industry standard of at least 10,000 ppm, or 1%, by more than five times. Therefore, this is a breakthrough performance figure considering that the existing photocatalyst technology only produces hydrogen peroxide at the level of tens to hundreds of ppm. This technology achieved a solar-to-chemical conversion efficiency of 1.1% through the synergistic effect of two photoreactions, i.e., photocatalyst and photochemistry, breaking the world's highest efficiency as well as the previous photocatalyst's highest efficiency of 0.61%. Dr. Byun and Dr. Lee of KIST said that “This study proves that low-carbon, eco-friendly technology using sunlight can also produce core industrial fuels with high concentration and purity.” They also mentioned, in their own words, that “We verified the completeness of the technology by linking the process of refining the produced hydrogen peroxide to a liter scale, and we will strive to commercialize the technology through large-scale demonstration in the future.” This research outcome is a novel technology achieved through convergence research between young scientists at KIST, which was conducted under the KIST Future Source National Technology Development Project, Excellent Emerging Research Project, Nano and Materials Technology Development Project, Biomedical Technology Development Project, and Advanced Convergence Research Project with the support of the Ministry of Science and ICT (Minister Jong-ho Lee). The results of this study were published as a cover paper in the latest issue of ‘Energy & Environmental Science’. [Figure] Schematic diagram of solar hydrogen peroxide production technology Cover of research achievement Source: Energy Environ. Sci., 2022, 15, 4853 DOI: 10.1039/D2EE90071H Title: Solar-driven H2O2 production via cooperative auto-and photocatalytic oxidation in fine-tuned reaction media Journal: Energy & Environmental Science DOI: https://doi.org/10.1039/D2EE02504C

- Complete replacement of existing petrochemical-based solvents with environmentally friendly solvents - Production of economically secured and environmentally friendly biofuels and renewable chemicals in a ‘one-pot process’ Biomass refers to biological organisms, including plants, that synthesize organic matter utilizing solar energy and animals that use these plants as food. Biomass also includes resources that can be converted into chemical energy. To achieve carbon neutrality by 2050, substantial efforts have been made worldwide to develop biorefinery technology that can replace fossil fuels with biofuels. However, the conventional biofuel production process involves the use of highly toxic solvents, which are mainly derived from petroleum causing environmental and economic concerns. Dr. Kwang Ho Kim’s research team at the Clean Energy Research Center of Korea Institute of Science and Technology (KIST, President Seok Jin Yoon) developed a green solvent that can completely replace conventional petrochemical-based solvents while maximizing the efficiency of biofuel production. The researchers announced that it is now possible to produce sustainable and economically secured biofuels. After screening various solvent candidates, the KIST research team synthesized a green deep eutectic solvent that is also biocompatible with microorganisms during the fermentation process. The synthesized eutectic solvents were systematically analyzed by advanced nuclear magnetic resonance spectroscopy and computational analysis. The ‘one-pot process’ based on the newly developed solvent maximized the production efficiency of high-purity biofuels and biochemicals by integrating three to four complex existing processes into one consolidated process. It was also announced that the one-pot process that uses environmentally friendly solvents is sustainable, does not emit pollutants, does not require washing water, and allows for the reuse of solvents. Dr. Kim of KIST said, “By overcoming the uneconomical problems currently being faced by the biorefinery industry via the development of green solvents and maximization of biofuel production process efficiency, Korea will be able to take the lead in the ‘Race to Zero’ by developing this sustainable technology.” This research was supported by by the KIST and the National Research Foundation of Korea (Minister Jong Ho Lee). This collaborative research was conducted between the University of British Columbia, State University of New York, National Institute of Forest Science of Korea and Korea Military Academy. The research results were published in the latest issue of Green Chemistry (Impact Factor: 11.034), an international journal in the energy and environment field and were selected as the back cover. One-pot process for producing biofuels and biochemicals from biomass using environmentally friendly eutectic solvents Title: One-pot conversion of engineered poplar into biochemicals and biofuels using biocompatible deep eutectic solvents Journal: Green Chemistry DOI: https://doi.org/10.1039/D2GC02774G

- Revealed cause of the reduced lifespan of manganese-based cathode materials, and expensive nickel is expected to be replaced - Battery strategy with improved lifespan by 62% with electrode-electrolyte interface stabilization technology Currently, most cathode materials used in batteries for electric vehicles are layered oxides composed of nickel for over 60% of the transition metals. Using nickel-rich layered oxide is advantageous in securing the mileage of an electric vehicle due to its high energy density, but its usage is limited by instability in the supply and demand of nickel raw materials. As an alternative, researchers focused on spinel cathode materials that use manganese as the main element, considering manganese is traded at a price of about 1/17 of nickel in the international spot market; however, the rapid decline in lifespan was an obstacle to commercialization. The Korea Institute of Science and Technology (KIST, President Seok Jin Yoon) announced that Dr. Jihyun Hong's research team at the Energy Materials Research Center identified the cause of the rapid decline in life span-a chronic problem of high-capacity manganese-based spinel cathode materials. This team worked on significantly increasing the possibility of commercializing lithium batteries with manganese cathode materials as next-generation electric vehicle batteries. Manganese-based spinel cathode materials can theoretically store energy with a high density comparable to nickel-based commercial cathode materials. Considering the price of metal raw materials, the energy density per price for manganese-based spinel cathode could reach 2.8 times that of nickel-based cathodes. However, when using the battery at full capacity, a rapid decrease in lifespan is observed; as a result, practically only approximately 75% of the theoretical value could be stored. It has been established that the trivalent manganese (Mn3+) formed during the charging and discharging process of manganese-based spinel cathode materials distorts the crystal structure of the material, leading to the elution of manganese into the electrolyte and eventually causing a reduction in the lifespan of the cathode material. As a result, most research has focused on suppressing the formation of trivalent manganese. Contrary to mainstream academic theories, Dr. Hong's team at KIST (first author: student researcher Gukhyun Lim) recently discovered that cathode materials exhibit excellent lifespan characteristics even when trivalent manganese is formed if the operating voltage range of the battery is adjusted. The research team utilized advanced material characterization techniques, including synchrotron radiation techniques, to interpret the phenomena that existing theories cannot explain. Through the thorough analyses, for the first time, it was identified that the side reaction at the interface between the cathode material and electrolyte during the repeated charging and discharging process is the cause of lifespan reduction. The research team further presented a key strategy to dramatically improve the lifespan of manganese-based materials by stabilizing the cathode-electrolyte interface. As an example of this strategy, introducing an EC-free electrolyte resulted in a 62% improvement in lifespan compared to commercial electrolytes. This improvement results in the highest capacity retention and rate capability among the performances of manganese-based spinel cathode materials simultaneously using nickel and manganese redox reactions reported so far. Dr. Hong of KIST said, "Through this research, KIST presented a new methodology for commercializing manganese-based high-energy cathode materials, which will be a catalyst for the expansion of electric vehicles." He also mentioned, "If academia and industry focus on applying the interface stabilization technology of nickel-based cathode materials, which has accumulated a lot of capabilities, to manganese-based next-generation cathode materials, we expect that Korean companies in the automobile industry could maintain a higher level of competitiveness in the future." This research was conducted under major KIST projects and Individual Research program (excellent young researcher, mid-career researcher) of the National Research Foundation of Korea with the support of the Ministry of Science and ICT (Minister Jong-ho Lee), with the research results selected as the full front cover page paper of 'Advanced Energy Materials' (IF: 29.698, top 2.464% in the JCR field), a world-renowned journal in the field of energy materials. [Figure 1] Selected image for the full front cover page paper [Figure 2] Changes in the price of cathode materials over the past three years (left), performance comparison of manganese-based cathode materials compared to other cathode materials (right). The square indicates the manganese-based cathode material studied with this achievement. [Figure 3] Newly identified maganese-based spinel cathode-electrolyte interface side reation mechanism Title: Regulating Dynamic Electrochemical Interface of LiNi0.5Mn1.5O4 Spinel Cathode for Realizing Simultaneous Mn and Ni Redox in Rechargeable Lithium Batteries Journal: Advanced Energy Materials DOI: https://doi.org/10.1002/aenm.202202049

- KIST develops nano filter manufacturing technology for heavy metal removal using coffee grounds - 150,000 tons annual domestic waste recycling path opened Only 0.2 % of the coffee beans used to make a cup of coffee become the actual coffee we drink, whilst the remaining 99.8% of the coffee grounds are thrown away. The amount of coffee waste generated this way is equivalent to approximately 150,000 tons per year in Korea alone. When coffee grounds are landfilled, greenhouse gases are generated and furthermore, when they are incinerated large volumes of carbon are generated. This poses a significant environmental issue, and as a result, a new method of recycling this to make a semiconductor wastewater purification material has been developed. The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) announced that Dr. Min Wook Lee’s research team at the Functional Composite Materials Research Center, in collaboration with Professor Young-Gwan Kim’s research team at the Department of Chemistry at Dongguk University, have succeeded in developing a nanocomposite filter for the removal of copper ions, by combining coffee grounds discarded as household waste with biodegradable polymers. Heavy metals in semiconductor wastewater can cause fatal damage to major human organs such as the kidneys, liver, and brain, whilst emissions have also increased due to the increase in recent semiconductor production. This explains why purification technology that can allow the effective removal of heavy metals, including copper, in semiconductor waste is needed. Since the surface of coffee grounds not only has a porous structure, but also consists of various functional groups with negative charges, it can be used to adsorb positively charged heavy metals in wastewater. However, since existing research has used methods such as dissolving coffee grounds in water, one limitation was that the used coffee grounds had to be collected again. Utilizing the composite material technology possessed by the KIST Jeonbuk Branch, the research team was able to collect coffee grounds in the commonly used capsule coffee and uniformly compounded them in a solvent with PCL (Poly Capro Lactone), a biodegradable plastic, without a specific pretreatment process such as washing or removing impurities. Then, this composite solution was electrospun to construct a nanocomposite filter composed of coffee grounds and biodegradable polymers in a very dense and uniform conformation. Within 4 h, the resultant material could achieve a heavy metal removal efficiency of 90 % or more from wastewater with an initial concentration of 100 μM (micromolar), whilst satisfying the drinking water standards. With one coffee capsule (approximately 5g), a nanocomposite filter capable of purifying approximately 10 L of wastewater could be manufactured. Dr. Min-Wook Lee of KIST stated, “This research is meaningful in that it developed an economical and environmentally friendly water treatment technology by simply making composite materials from waste, which is the cause of environmental pollution,” he continued, “In the future, we plan to surface-treat coffee grounds or explore other natural materials to develop various filters that are environmentally friendly and have high performance.” The results of this research are expected to not only lead the semiconductor process, which is a key national industry, but also to suggest solutions for problems that the coffee industry has been struggling with, and lead global environmental issues. This study was conducted with the support of the Nano·Material Technology Development Program (Material Innovation Leading Project) of the Ministry of Science and ICT and the Carbon Reducing Petroleum Raw Material Alternative Chemical Process Development Project of the Ministry of Trade, Industry, and Energy. The research results were published online in the latest issue of Journal of Water Process Engineering (IF: 7.34, top 7.5 % in JCR field), an international academic journal in the field of water resource treatment. [Figure 1] Conceptual diagram of the nanocomposite filter Schematic diagram of the process in which heavy metal ions contained in semiconductor wastewater are removed through a nanocomposite filter and become drinking water. This expresses the process of the rebirth of coffee grounds into a nanocomposite filter [Figure 2] Nanocomposite filter micrograph A composite filter made of Polycaprolactone (PCL) fibers and coffee particles

- A detoxification coating achieved on various materials by complexation of a detoxification catalyst through functional polymer design - Expected to contribute to next-generation protective suits and equipment, as well as to detoxification treatment of chemical leakage Highly toxic organic compounds are colorless, odorless, and can be used to perpetrate massacres in very small amounts; thus, their use is prohibited by the Chemical Weapons Convention worldwide. Nevertheless, there have been reports of chemical weapon use recently, and therefore, there is an emerging need to develop protective materials against such threats. Currently, activated charcoals are used in protective suits and gas masks to remove toxic chemicals by absorption, but they have their own problems, such as secondary contamination; thus, the development of detoxification catalysts that can fundamentally remove toxicity is required. The Korea Institute of Science and Technology (KIST, President Yoon Seokjin) announced that the research team led by Dr. Baek Kyung Youl, a senior researcher at the Materials Architecturing Research Center, succeeded in developing a detoxification composite that can be easily processed into a coating material, continuing on their success in developing a nano-based detoxification catalyst in 2019. The previously developed metal-organic framework (MOF) detoxification catalyst had high performance, but was in the form of particles that break like sand; thus, it had not been put into practical use in coating military uniforms and equipment. To overcome this problem, Baek’s research team designed a functional polymer and mixed it with a detoxification catalyst to develop a detoxification technology that can be processed into films and fibers while maintaining its properties. The research team developed a new functional polymeric support that improves processability while maintaining the high reactivity of the previously developed nanometer-level zirconium (Zr)-based detoxification catalyst, and used it to make a mixed compound that can be used as a detoxification catalyst. It was confirmed to be practically applicable in a detoxification performance test using an actual chemical weapon, the nerve agent soman (GD), on military uniforms and equipment coated with the compound. Dr. Baek of KIST said, “What is different about this compound is that it can remove the toxicity of chemical weapons easily and coat large areas quickly using a simple spray process rather than the conventional electrospinning method”, and that “It is expected that the spray coating can be applied to military uniforms and equipment to prevent contamination and be used to remove toxic agents from equipment, protecting the lives of soldiers and civilians from highly toxic chemical agents.” This study was conducted with the support of the K-DARPA project of KIST and in cooperation with KIST’s Department of National Security, Disaster and Safety Technology. The results of the study have been published online in the latest issue of ACS Applied Materials & Interfaces (IF: 10.383, JCR Top 14.05%). [Fig. 1] Schematic diagram of the strategy for the development of coating materials using the functional polymeric support and nano-detoxification catalyst and the decomposition of chemical agents [Fig. 2] Detoxification catalyst powder developed by KIST researchers (left) and a glass substrate coated with the detoxification catalyst (right)

- Photocatalysis-based Prompt and Complete Removal of Trace Amount of Alcohol in Water Alcohols are used to remove impurities on the surface of semiconductors or electronics during the manufacturing process, and wastewater containing alcohols is treated using reverse osmosis, ozone, and biological decomposition. Although such methods can lower the alcohol concentration in wastewater, they are ineffective at completely decomposing alcohols in wastewater with a low alcohol concentration. This is because alcohol is miscible in water, making it impossible to completely separate from alcohol using physical methods, while chemical or biological treatments are highly inefficient. For this reason, wastewater with a low alcohol concentration is primarily treated by diluting it with a large amount of clean water before its discharge. The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) has announced that a research team led by Dr. Sang Hoon Kim and Dr. Gun-hee Moon of Extreme Materials Research Center developed a photocatalyst that can completely decompose a trace amount of alcohol in water within a short duration by adding a very trace amount of copper to iron oxide, which is used as a catalyst during the advanced oxidation process. The research team employed Fenton oxidation that uses oxidizing agents and catalysts during the advanced oxidation process for water treatment. Usually alcohols were used as reagents to verify radical production during Fenton oxidation in other advanced oxidation process (AOP) studies, they were the target for removal from semiconductor wastewater in this research. This water treatment technology is expected to dramatically reduce the cost and water resources invested into the treatment of semiconductor wastewater. In the past, clean water with a volume 10 times higher than that of the wastewater under treatment was required for dilution of the wastewater in order to reduce the alcohol concentration of 10 ppm in the wastewater to less than 1 ppm. If the photocatalyst developed by the KIST is used for water treatment, water resources can be saved. The research team applied the photocatalyst to wastewater from a semiconductor factory to prove that alcohol decomposition levels similar to those observed in the laboratory could be achieved in industrial practice. “As large-scale semiconductor production lines are established, we expect that there will be a rapid increase in the demand for the treatment of semiconductor wastewater,” said Dr. Kim. “The results of our research will provide a solution to effectively treat semiconductor wastewater using less resources and at a lower cost,” he added. Image [Figure 1] Mechanism of Isopropyl alcohol (IPA) decomposition during photo-Fenton oxidation using the developed catalyst

Hydrogen is considered a future clean energy source, and thus, building infrastructure and developing core technologies for hydrogen production, storage, transportation, and utilization has attracted significant attention. Among the various hydrogen storage methods, metal hydride-based hydrogen storage systems are considered the safest method to store hydrogen. The Korea Institute of Science and Technology (KIST, President Seokjin Yoon), headed by Dr. Dong Won Chun and Dr. Jin-Yoo Suh, the research teams of the Energy Materials Research Center, and Prof. Kyu Hyoung Lee from the Yonsei University (President Seoung-Hwan Suh), along with their research team, succeeded in the real-time monitoring of the dehydrogenation of metal hydride composites made of Mg and Fe with high nanometer-scale resolution. The joint research team observed the transition of hydrogen atoms from their initial state inside a metal hydride solid to the gaseous state as they move from the outside and calculated the amount of hydrogen that remains inside the metal hydride after the dehydrogenation process. Meanwhile, physical properties of metal hydride were investigated by observing nano-sized samples through an electron microscope; therefore, the reliability of results is questionable. However, the researchers verified that the same phenomenon is reproduced in an experiment when the nano-sized sample (100 nm) is compared with bulk-sized metal hydrate samples (several mm) produced for commercialization. By minimizing sample damage caused by the electron beam, it is possible to observe the movement of hydrogen within the metal, bringing a new phase in the development of hydrogen storage. Dr. Chun said "Hydrogen, with atomic number 1, has one electron and one proton, so it is difficult to observe its movement at the current level of technology, which analyzes the signal of electrons or protons. The research team has introduced a new methodology to observe hydrogen movement within solids. We will apply this technology to the new national challenge of developing solid hydrogen storage systems to build a safe hydrogen storage infrastructure. The final goal is to make hydrogen energy widely available in our daily lives." The research was supported by the Ministry of Science and ICT (Minister Jong-Ho Lee) and was carried out as a major KIST project and as a mid-career researcher project by the National Research Foundation of Korea. The results were published in the latest issue of “Advanced Functional Materials”, a specialized journal on materials and energy. Figure 1. Real-time analysis of hydrogen atom movement and metal hydride dehydrogenation process. Figure 2. Quantification results of hydrogen mobility through observation of hydrogen inside metal hydride. Journal : Advanced Functional Materials Title : Real-Time Monitoring of the Dehydrogenation Behavior of a Mg2FeH6-MgH2 Composite by In Situ Transmission Electron Microscopy 2022.07.19. DOI: https://doi.org/10.1002/adfm.202204147

- Utilization of new two-dimensional materials as thin as a single atomic layer - Development of semiconductor devices that operate at low energy like human synapses The Korea Institute of Science and Technology (KIST, President Yoon Seokjin) announced that the research team of Dr. Joon Young Kwak at the Artificial Brain Convergence Research Center developed a new two-dimensional insulator material synthesis technology with a new element composition ratio, as well as a high-performance and low-power artificial synaptic semiconductor device using this new material, through joint research with Professor Ki-beom Kang's team at the Korea Advanced Institute of Science and Technology (KAIST) and Dr. Taek-mo Jeong's team at the Korea Research Institute of Chemical Technology (KRICT). With the recent increase in the proportion of video and image data, the processing of unstructured data is drawing attention as a key factor in the development of future artificial intelligence (AI) systems. In line with this trend, to overcome the excessive power consumption and limited information processing performance of the current widely used von Neumann computing structure, a “neuromorphic system” that can process and learn information with high efficiency and low power consumption is emerging as a next-generation semiconductor system. Neuromorphic systems mimic the human brain to increase computing performance while reducing power consumption. To implement this, it is necessary to develop high-performance next-generation semiconductor devices that can precisely simulate “synapses” that regulate the connection strength between neurons according to the input signals. Silicon-based semiconductor devices, which are predominantly used at present, consume much more energy than biological synapses, and have physical limitations in simulating a highly integrated system similar to a real nervous system. For this reason, research is actively being conducted to realize high-performance artificial synaptic devices by applying the properties of materials such as oxides and organic/inorganic materials. In addition, newly emerging two-dimensional materials are very thin at the atomic level, which gives them a great advantage in high integration of semiconductor devices. They have superior performance compared to existing silicon materials, such as fast switching speed and charge transfer speed, due to their unique characteristics. The joint research team developed a synaptic device based on a new 2D insulator material and a heterojunction structure of a 2D semiconductor, enabling electrons to move efficiently even at low energy. Using these physical characteristics, they succeeded in developing an artificial synaptic device that shows uniform synaptic connection strength change and operates with an energy of about 15 fJ, which is similar to the actual energy consumption of human synapses. In addition, synaptic connection strength can be maintained for a short or long time depending on the number and intensity of external stimuli, enabling more precise simulation of human brain functions. The research team attempted artificial intelligence learning based on the developed high-performance two-dimensional artificial synaptic device, and the classification accuracy of handwritten digit image data (MNIST) was about 88.3%, confirming the possibility of application to actual neuromorphic systems. Dr. Kwak of KIST said, “As the importance of research on high-efficiency new materials that can be used as substitutes for silicon in the development of next-generation semiconductors is growing, synaptic devices based on the heterojunction structure of semiconductors and the new two-dimensional insulator material presented in this study should have excellent competitiveness in implementing high-level neuromorphic hardware that can accurately simulate brain behavior." This research was carried out with the support of a KIST institutional research program, the Next-Generation Intelligent Semiconductor Technology Development Project of the National Research Foundation of Korea, and the New Concept PIM Semiconductor Leading Technology Development Project of the National Institute of Information and Communications Technology Evaluation. The research results were published in the latest issue of the international journal Advanced Materials (IF: 32.086). [Core Figure (Main)] Characteristics of the low-power, high-performance artificial synapse (left) and image classification learning accuracy test (right) of the new 2D-material-based artificial synaptic device developed by the research team. [Reference figure] Synthesis technology developed by the research team and structure and analysis of the new 2D material.

Due to unusual weather conditions caused by global warming, countries around the world have been suffering from disasters such as extreme heat waves, droughts, and floods in recent years, raising a sense of crisis. Meanwhile, Korean researchers have developed a new catalyst material to realize the resourceization of carbon dioxide, one of the causes of greenhouse gases that cause global warming. Korea Institute of Science and Technology (KIST, President Yoon Seokjin) announced that the team of Dr. Hyung-Suk Oh and Dr. Woong Hee Lee at the Clean Energy Research Center developed a nickel sulfide catalyst used to convert carbon dioxide, the main culprit of greenhouse gases, into carbon monoxide, which is used as a raw material for industries. When the catalyst was applied to the actual conversion systerm, the carbon dioxide conversion performance was three times or more than that of the existing nickel single atom catalyst. Carbon dioxide accounts for most of the substances that cause global warming and has the greatest impact on the greenhouse effect. Through an electrochemical reduction reaction, carbon dioxide can be converted into useful compounds such as carbon monoxide, ethylene, antacid, and methanol. Therefore, research to collect, utilize, and store carbon dioxide is being actively carried out. In particular, carbon monoxide (CO) is a very important basic raw material in the industry. Since carbon monoxide is very chemically unstable, it is mainly used as a reducing agent in the chemical, metal and electronic industries. It also has the highest economic value among chemical materials that can be made of carbon dioxide because of its high production compared to energy input. Research on converting carbon dioxide into carbon monoxide has been based on presioud metal catalysts such as expensive silver and gold. For full-scale commercialization, the development of inexpensive catalyst materials is the key. A nickel(Ni)-based single atom catalyst has been developed as an alternative to a precious metal catalyst, but there is a limit to the conversion rate of carbon dioxide, that is, the maximum current amount, being low. The KIST research team proposed a relatively inexpensive nickel sulfide catalyst and applied it to an actual system to confirm that its performance was high. It was known that only nickel in a single atomic state can be used for carbon dioxide conversion, and nickel catalysts in other metalic states are not possible. However, the research team confirmed though operando analysis that the nickel sulfide catalyst exhibits high electrochemical carbon dioxide conversion activity by simulating the electroninc structure of the single atomic nickel catalyst during the reaction. In addition, it has been confirmed that power efficiency (Faradaic efficiency 3) is also improved by more than three times (70%) compared to the existing nickel monatomic catalyst (22%) Dr. Oh of KIST said, "The nickel sulfide catalyst material, which was simulated by analyzing the reaction and behavior of the nickel single atom catalyst in real time, was born through an original catalyst research and development method called electronic structure imitation. The significance of the study is that it presented new possibilities for developing various low-cos catalysts." He also said, "We plan to make efforts to quickly commercialize nickel sulfide catalysts through follow-up studies such as long-term durability in the future." With the support of the Ministry of Science and ICT (Minister Lee Jong-ho), this study was conducted as a KIST institutional program, 'Carbon to X Project', and a 'Creative Convergence Research Project' by the National Science and Technology Research Association (Chairman Kim Bok-cheol). It was also published in the latest issue of Advanced Energy Materials, an international journal in the field of energy and environment (IF: 29.698, the top 2.464% in the field of JCR).

- KIST discovered critical variables to maximize the performance of artificial synaptic devices - Green light for next-generation neuromorphic system development Neuromorphic computing system technology mimicking the human brain has emerged and overcome the limitation of excessive power consumption regarding the existing von Neumann computing method. A high-performance, analog artificial synapse device, capable of expressing various synapse connection strengths, is required to implement a semiconductor device that uses a brain information transmission method. This method uses signals transmitted between neurons when a neuron generates a spike signal. However, considering conventional resistance-variable memory devices widely used as artificial synapses, as the filament grows with varying resistance, the electric field increases, causing a feedback phenomenon, resulting in rapid filament growth. Therefore, it is challenging to implement considerable plasticity while maintaining analog (gradual) resistance variation concerning the filament type. The Korea Institute of Science and Technology (KIST, President Yoon Seok-jin), led by Dr. YeonJoo Jeong’s team at the Center for Neuromorphic Engineering, solved the limitations of analog synaptic characteristics, plasticity, and information preservation, which are chronic obstacles regarding memristors, neuromorphic semiconductor devices. He announced the development of an artificial synaptic semiconductor device capable of highly reliable neuromorphic computing. The KIST research team fine-tuned the redox properties of active electrode ions to solve small synaptic plasticity hindering the performance of existing neuromorphic semiconductor devices. Furthermore, various transition metals were doped and used in the synaptic device, controlling the reduction probability of active electrode ions. It was discovered that the high reduction probability of ions is a critical variable in the development of high-performance artificial synaptic devices. Therefore, a titanium transition metal, having a high ion reduction probability, was introduced by the research team into an existing artificial synaptic device. This maintains the synapse’s analog characteristics and the device plasticity at the synapse of the biological brain, approximately five times the difference between high and low resistances. Furthermore, they developed a high-performance neuromorphic semiconductor that is approximately 50 times more efficient. Additionally, due to the high alloy formation reaction concerning the doped titanium transition metal, the information retention increased up to 63 times compared with the existing artificial synaptic device. Furthermore, brain functions, including long-term potentiation and long-term depression, could be more precisely simulated. The team implemented an artificial neural network learning pattern using the developed artificial synaptic device and attempted artificial intelligence image recognition learning. As a result, the error rate was reduced by more than 60% compared with the existing artificial synaptic device; additionally, the handwriting image pattern (MNIST) recognition accuracy increased by more than 69%. The research team confirmed the feasibility of a high-performance neuromorphic computing system through this improved the artificial synaptic device. Dr. Jeong of KIST stated, “This study drastically improved the synaptic range of motion and information preservation, which were the greatest technical barriers of existing synaptic mimics.” “In the developed artificial synapse device, the device’s analog operation area to express the synapse’s various connection strengths has been maximized, so the performance of brain simulation-based artificial intelligence computing will be improved.” Additionally, he mentioned, “In the follow-up research, we will manufacture a neuromorphic semiconductor chip based on the developed artificial synapse device to realize a high-performance artificial intelligence system, thereby further enhancing competitiveness in the domestic system and artificial intelligence semiconductor field.” Image [Figure 1] Concept image of the article [Figure 2] Example of visual information processing technology using the artificial synaptic device, confirming that the error rate is reduced by more than 60% by improving the device performance [Figure 3] Photographs of (a) Solar Energy Collector, (b) Membrane Distillation System