Scaling Up Photocatalysts and New Devices for Solar Water Splitting and CO2 Reduction

Artificial photosynthesis using semiconductor materials is considered to be an attractive approach to converting solar energy into chemical fuels. The development of a scalable artificial photosynthesis system is one of the most important issues for practical applications. In this chapter, recent advantages for the practical use of solar H2 production via photocatalytic water splitting and formate production via CO2 reduction are discussed. Large-scale H2 production has been demonstrated for the first time using a 100 m2 sized panel reactor comprised of UV-light-driven photocatalyst sheets. In addition, visible-light-driven printable photocatalyst sheets, which can be prepared inexpensively and easily extended to scalable applications, are explored. Also, large-scale formate production over a CO2 reduction system using a new molecular catalyst is demonstrated. These approaches are an essential step toward any future practical applications.