Demonstration of Scalable Water Splitting into H and O by a Flow-Type Photocatalysis-Electrolysis Hybrid System Using a Highly Stable Photocatalyst.

Water splitting via a photocatalysis-electrolysis hybrid system has been investigated as a potentially scalable and economically feasible means of producing renewable H. However, there are no reports demonstrating a scalable system for stoichiometric water splitting using an efficient and stable photocatalyst, and the key operating conditions for efficiently driving the entire system have not been established. Herein, we address the issues required to efficiently drive the entire system of a Cs, Fe, and H ion-modified WO (denoted as H-Fe-Cs-WO) photocatalyst fixed reactor combined with a polymer electrolyte membrane (PEM)-type electrolyzer.