 에너지 사용은 우리의 일상에 대한 fundamental importance is greatest impact on the environment. 에너지와 환경에 관한, such as the depletion of fossil fuels and greenhouse gas effects are global issues and become the subject of international debate and regulations. 그래서, 에너지의 기지와 공감의 필요는 strong need for developing renewables such as solar and wind power. Renewable energy is gaining ground. Global electricity share from renewables is already about 20%. However, the challenge is how to store surplus energy and how to address its intermittency. Here, we have a solution for the challenge. That's hydrogen from water. Hydrogen is the most abundant element on the earth and on extremely clean fuel because they come back to water when they are used as a fuel. And hydrogen is as safe as gasoline and natural gas. In the hydrogen fuel economy, we use the surplus energy on sunny days to split hydrogen from water through electrolysis. The produced hydrogen is stored and fed to fuel cells to generate electricity when needed. Here, we have a core device of electrolyzer and fuel cells. Hydrogen fuel can be applied to transportations as well as for homes, buildings and industries. In evolving into hydrogen society, one of the critical issues in science and technology is catalysts. Conversion of electricity into hydrogen and hydrogen into electricity occurs only on the surface of precious metal catalysts. To minimize use of precious catalysts, we have to maximize surface area of the material using the nanotechnologies. By dividing a one centimeter cube into one nanometer cube, we can enlarge surface area of the materials by 10 million times. The first innovation people made was to disperse nanoparticles on a support to prevent agglomeration of those two or three nanometers tiny particles. Currently, about 50 grams of platinum is used for one-fierce electric vehicles in this finely dispersed form. That's too much, we have to reduce it. For that, we can control shape of the nanoparticles. Each of the involved reactions pre-pulls a specific furship. So by exposing the preferential furship as much as possible, we can reduce use of those precious metal catalysts. Or we can add a secondary chip element to precious metal catalysts. By allowing platinum with cobalt or iron sometimes combined with the shape controlling technology, we can enhance catalytic activity of those nanoparticles with less amount of precious metal catalyst. We can fill inside of the nanoparticles with the chip metal element and coat the core with precious element in several monolayers. My group developed a coercial structures of catalysts of palladium, kappa core, and platinum shell and could reduce use of platinum catalyst by about 30%. Our ultimate target is to completely replace the precious element with non-precious catalyst. Recent studies have reported that the catalytic activity of structure and composition controlled carbon nanomaterials is approaching to that of precious metal catalysts. In my group, we developed carbon nanofibers, hollow carbons, and graphing catalysts for fuel cells and electrolyzers. These catalysts exhibit comparable performance with conventional platinum catalysts. Those non-precious catalysts are expected to reduce the fuel cell fabrication cost by about 40%. At present, fuel cell electric vehicles are released to public and learning industry. In terms of driving range and ease of refuelling, they provide similar convenience to today's gasoline vehicles. The final hurdle for market growth will be the cost associated with the platinum catalyst. We already began to shift from fossil fuels to hydrogen fuels throughout greater energy security. Nanomaterials will be the key to the revolution by ensuring the economic visibility. Imagine living in a world with our concerns about energy security and pollutant with the help of nanomaterials. Thank you.