Research

Reseach and Development of High-Efficiency Energy Conversion System Using Sunlight, Water and Hydrogen for the Nonuse of Fossil Fuels

Research and Development of High-Efficiency Energy Conversion System Using Sunlight, Water and Hydrogen for the Nonuse of Fossil Fuels

Nagahiro Hoshi

Professor, Graduate School of Engineering, Chiba University

Professor Nagahiro Hoshi graduated from the Faculty of Science and the Graduate School of Science, Kyoto University. He joined the faculty of Chiba University in 1991 and was appointed to the current post in 2011. He has been serving as chair of the nano surface study group of the Electrochemical Society of Japan since 2010. He specializes in surface electrochemistry. In surface reaction, the rate of surface reaction and distribution of products depend significantly on the arrangement of atoms. Professor Hoshi is conducting research on high-precision regulation of surface structures at molecular and atomic levels to enhance the efficiency of energy conversion. More recently, he is pouring energy into research on oxygen reduction reaction that occurs in the air cathode of fuel cell and on improving the efficiency of photovoltaic power generation by changing the direction of adsorption of dye molecules used in photovoltaic power generation.

Establishment of an energy system that does not emit any carbon dioxide or hazardous substances

Leveraging the world-class technology in regulating the atomic and molecular arrangements and combining photovoltaic power generation, hydrogen manufacturing that uses light to break down water, and fuel cell that uses hydrogen and light, we aim to build an energy system that departs completely from the use of fossil fuels.

Thermal power generation that burns fossil fuels to generate power emits carbon dioxide that causes the greenhouse effect. On the other hand, hydrogen is a clean energy that emits only water when burned. However, hydrogen is manufactured today mainly by reforming fossil fuels, emitting carbon dioxide in that process.

In this research, we aim to build an energy system that does not emit any carbon dioxide or hazardous substances by using sunlight, which is a natural energy, and water to generate power and produce hydrogen, thereby staving off degeneration of the global environment (Fig. 1). The efficient use of abundant solar energy will also free us from the issue of depletion of fossil fuels.

Collaboration among one-of-a-kind researchers at Chiba University and outstanding researchers from around the world

The research will be conducted by four groups led by five people, namely, Nagahiro Hoshi and Masashi Nakamura, Yasuo Izumi, Shiki Yagai, and Takashi Kojima (Fig.2).
The research will be carried out as follows (Fig. 3-6)
■ Hoshi and Nakamura Group: This group will oversee all of the research groups. It will regulate surface atomic arrangements to elevate efficiency of fuel cells, photovoltaic power generation, and hydrogen manufacturing, and explore causes of increased efficiency.
■ Izumi Group: This group will develop unique photofuel cells that generate power using light and water.
■ Yagai Group: In collaboration with Hoshi and Nakamura Group, this group will develop organic dye molecules that efficiently collect visible radiation from sunlight and increase the efficiency of photovoltaic power generation and hydrogen manufacturing.
■ Kojima Group: Working with the other research group, this group will develop, for practical application, technology for regulating, at the atomic level, the surface structures of nanoparticles of titanium oxide, which provide the field of reaction for photovoltaic power generation, photofuel cells, and hydrogen manufacturing.

Hoshi and Nakamura Group, Yagai Group, and Kojima Group are the world's leaders in technology to regulate the surface atomic arrangements of metal and titanium oxide, technology to regulate the structures of organic aggregates, and technology to regulate the structures of titanium oxide nanoparticles, respectively. Izumi Group's concept of photofuel cell is exceptionally unique. Because photofuel cell is portable, it is expected to have wide social application as a power source for mobile devises and outdoor use. It can also compete with other power sources because of its cost advantages of not using platinum or silicon, making it a cheaper power source.
Collaboration among one-of-a-kind researchers at Chiba University and other outstanding researchers from around the world is expected to produce significant research results. We will gather a select group of leading researchers not only from Chiba University but also from around the world to develop the world's most advanced energy system that does not rely on fossil fuels.

Message to students and young researchers

Let's together engage in research at Chiba University that aims to develop the world's most advanced energy conversion technology with the world's leading researchers.

Figure 1
Research goal and outlines

Figure 2
Novelty and originality

Figure 3
Analysis of the status of the research field

Figure 4
Approaches to implementing the plan (dye solar cell)

Figure 5
One-of-a-kind technology for implementing the plan (1)

Figure 6
One-of-a-kind technology for implementing the plan (2)