Lee Hsun Lecture Series

Topic: PHOTOCATALYTIC WATER SPLITTING FOR LARGE SCALE SOLAR HYDROGEN PRODUCTION

Speaker: Prof. Kazunari. Domen

　　　　Shinshu University, Nagano;The University of Tokyo, Tokyo, Japan

Time: 10:00-11:30, (Fri.) May.17th, 2019

Venue: Room 468，Lee Hsun Building, IMR CAS

Abstract:

Sunlight-driven photocatalytic water splitting has attracted much attention as a means of renewable hydrogen production on a large scale.¹ A solar-to-hydrogen energy conversion efficiency (STH) of 3% or higher is necessary to make the process feasible. The scalability of water splitting systems is another important consideration. The development of particulate photocatalysts driving overall water splitting efficiently has a significant impact because such systems can be spread over large areas using inexpensive solution processes.

The author’s group has developed various kinds of photocatalyst sheets, one of which consisting of La- and Rh-codoped SrTiO₃ for H₂ evolution and Mo-doped BiVO₄ for O₂ evolution embedded into a conductor layer for Z-scheme water splitting.² The photocatalyst sheet splits water efficiently because the conductor layer transfers photogenerated electrons between photocatalyst particles effectively. The photocatalyst sheet based on a carbon conductor exhibits a STH of 1.0% at an ambient pressure, which is outstanding among particulate photocatalyst systems.

We have been also developing panel-type reactors that accommodate photocatalyst sheets effectively in view of large-scale application.³ Al-doped SrTiO₃ photocatalyst sheets contained in a panel-type reactor split water and release gas bubbles at a rate corresponding to a STH of 10% under intense UV illumination even when the water depth is merely 1 mm. A 1-m²-sized photocatalyst panel reactor splits water under natural sunlight irradiation without a significant loss of the intrinsic activity of the photocatalyst sheets.

In addition to these systems, several new photocatalysts which works using wide range of visible light will be reported.^4,5 A pilot scale plant of the area of 100 m², which is under construction, will be discussed from the view point of practical solar hydrogen production.

1. T. Hisatomi et al., Faraday Discuss., 2017, 198, 11.

2. Q. Wang et al., Nat. Mater., 2016, 15, 611.

3. Y. Goto et al., Joule, 2018, 2, 509.

4. Z. Wang et al., Nature Catal., 2018, 1, 756.

5. Q. Wang et al., Nature Mater., accepted.