Unit name: Nano Green

Key words: environment/energy, CO₂ reduction, element strategies, catalysts, utilization of carbon

       The amount of CO₂ emitted around the world as a result of people’s activities is continuing to increase. In recent years, it has become increasingly necessary to develop a CO₂-free hydrogen-based society. With the aim of supporting the Japanese society in which advanced scientific technologies can be developed without increasing the burden on future generations, the research unit focuses on the generation of energy utilizing catalytic functions. Members of the unit promote the research and development of catalysts composed of inexpensive and safe elements based on the scientific design guidelines, rather than through trial and error, while avoiding the use of platinum (Pt) and other valuable resources.

Research and development on high-efficiency catalysts to support a hydrogen-based society

       The most realistic and rational approach to the reduction of CO₂ emissions from the viewpoints of high generation efficiency and the reduction of required energy is to facilitate the reaction of CO₂ with hydrogen to generate methanol. Furthermore, the use of hydrogen fuel cells, which emit H₂O, rather than CO₂, will contribute to the development of environmentally friendly societies at a global level (Figure 1). Hydrogen is required to both reduce the excessive amount of CO₂ in the atmosphere and develop new fuel cell systems. To facilitate methanol synthesis using CO₂, it is necessary to activate CO₂ on the surface of a catalyst. Hydrogen atoms are adsorbed to the surface of copper (Cu) and ultrafast CO₂ molecular beams are applied to it to activate CO₂ with a highly symmetric structure and convert it into methanol. Although research and development on catalysts often rely on trial-and-error approaches, the research unit aims to integrate knowledge obtained from the fields of computational and surface science to establish physicochemical foundations, and provide society with engineering technologies based on them.

Figure 1. Concept of research on catalysts that contribute to a hydrogen-based society

Utilization of hydrogen for fuel cells and the generation of hydrogen using algae

Figure 2. An STM image of an N-containing graphene and its STS spectrum (STM: scanning tunneling microscopy, STS: scanning tunneling spectroscopy)

       Fuel cells are becoming increasingly popular as energy sources for automobiles and at home. Pt is used as a cathode electrode catalyst at present, and there has also been progress in research on the utilization of π electronic carbons from the viewpoints of price reduction and effective utilization of scarce resources. The research aims to utilize the edge effects of graphen (a substance consisting of a layer of carbon (C) atoms) to which nitrogen is added and nano carbon. The research unit has confirmed that, although the electronic state of graphen is significantly homogenous, the state differs depending on the atoms in perivascular areas, as shown in Figure 2. The research unit aims to develop new catalysts by promoting a basic understanding of carbon nanostructures whose chemical characteristics have not been clarified. The unit plans to generate hydrogen, which is used for methanol synthesis and fuel cells, from algae since the University of Tsukuba has been conducting advanced research on them.

       The development of scientific technologies has conventionally been going through the process of basic science (seeds), applied research, practical research, and practical use. However, as the speed of changes increases and competitions become more severe in modern society, it has become increasingly important for people who conduct basic research to place an emphasis on its acceptance by society. The research unit collaborates with industries to conduct basic research, so that the research results can be put into practice smoothly, while addressing problems to promote their application to the industrial world and society.

Interviewed on July 31, 2015