报告摘要：Photocatalytic water splitting is of growing interest as a means of producing renewable hydrogen, because systems based on particulate photocatalysts can be spread over large areas using potentially inexpensive processes. The author’s group has studied various photocatalytic materials and reaction systems for water splitting. The apparent quantum yield (AQY) of overall water splitting using SrTiO₃ has been improved to more than 90% at 365 nm, corresponding to an internal quantum efficiency close to unity, by refining the photocatalyst preparation conditions and the cocatalyst loading conditions. Recently, a solar hydrogen production system based on 100 m² arrayed photocatalytic water splitting panels and an oxyhydrogen gas separation module was constructed, and its performance and system characteristics, including safety issues, were reported. However, it is essential to radically improve the solar-to-hydrogen energy conversion efficiency (STH efficiency) of particulate photocatalysts and develop suitable reaction systems.

The author’s group found that particulate photocatalyst sheets consisting of La- and Rh-codoped SrTiO₃ as HEP and Mo-doped BiVO₄ as OEP immobilized on Au thin film by the particle transfer method split water into hydrogen and oxygen with a remarkable STH of 1.1%. The water splitting activity decreases with increasing reaction pressure due to the oxygen reduction reaction, a representative reverse reaction. The above photocatalyst sheet requires a vacuum process during fabrication. It is desired to construct efficient Z-scheme systems in a more facile manner considering the need of scaling up the reaction system. A reduced graphene oxide (rGO), a carbon-based electron mediator, has been used to construct Z-scheme systems free of redox mediators. The author’s group recently found that a Z-scheme system comprising Sm₂Ti₂O₅S₂ as the HEP and rGO-loaded BiVO₄, both of which showed high activity in the corresponding half-reactions with suitable cocatalyst loading, exhibited water splitting activity regardless of whether the photocatalysts were suspended in water or immobilized on a substrate.

In my lecture, the latest advancements in photocatalytic water splitting systems will be discussed.

报告人简介：

Prof. Kazunari Domen（堂免一成先生），分别于1976年、1979年、1982年在东京大学科学学院获得学士、硕士、博士学位。1982-2004年在东京工业大学从事助理研究员、副教授和教授， 2004年至今任东京大学工学院化学工程系教授，2017年起在日本信州大学能源与环境科学中心担任特聘教授。获得的荣誉奖项有：2007年获日本催化协会奖，2011年获日本化学会奖。研究兴趣有：光催化分解水研究、基于红外光谱的多相催化研究、基于非线性激光光谱的表面动力学反应研究，以及新型功能化催化材料的开发。