A composite protective layer for a photoelectrode, the composite protective layer including a chemical protective layer; and a physical protective layer, wherein the chemical protective layer has corrosion rate of 0.1 Coulombs per square centimeter per 10 ...

A photoelectrochemical cell (100) includes: a semiconductor electrode (120) including a conductor (121), a first n-type semiconductor layer (122) having a nanotube array structure, and a second n-type semiconductor layer (123); a counter electrode (130) co...

A hydrogen generation system (2A) includes a hydrogen generation unit (201) that holds a first liquid containing water and that allows a part of the water contained in the first liquid to be decomposed into hydrogen and oxygen, and at least a part of the f...