In these devices the semiconductor surface absorbs solar energy and acts as an electrode for water splitting.

So equilibrium would be maintained with oxygen recombination being continually counter-balanced by water splitting.

Furthermore, the protons resulting from water splitting can be used for hydrogen production.

Conversion of water to hydrogen gas by photocatalytic water splitting.

Efficient and economical water splitting would be a key technology component of a hydrogen economy.

Thermal water splitting has been investigated for hydrogen production since the 1960s.

(In this case, the process is sometimes known as water splitting or splitting water.)

Water oxidation is one of the half reactions of water splitting:

There are several strict requirements for a photocatalyst to be useful for water splitting.

Photocatalysts must conform to several key principles in order to be considered effective at water splitting.