Photoelectrochemical water splitting in separate

oxygen and hydrogen cells

Avigail Landman1, Hen Dotan2, Gennady E. Shter3, MichaelWullenkord4, Anis Houaijia4,

Artjom Maljusch5, Gideon S. Grader3* and Avner Rothschild2*

Solar water splitting provides a promising path for sustainable hydrogen production and solar energy storage. One of

the greatest challenges towards large-scale utilization of this technology is reducing the hydrogen production cost. The

conventional electrolyser architecture, where hydrogen and oxygen are co-produced in the same cell, gives rise to critical

challenges in photoelectrochemical water splitting cells that directly convert solar energy and water to hydrogen. Here we

overcome these challenges by separating the hydrogen and oxygen cells. The ion exchange in our cells is mediated by auxiliary

electrodes, and the cells are connected to each other only by metal wires, enabling centralized hydrogen production. We

demonstrate hydrogen generation in separate cells with solar-to-hydrogen conversion eciency of 7.5%, which can readily

surpass 10% using standard commercial components. A basic cost comparison shows that our approach is competitive with

conventional photoelectrochemical systems, enabling safe and potentially aordable solar hydrogen production.