In photocatalytic hydrogen production, light energy is absorbed by a semiconductor material, generating electron-hole pairs. These charge carriers drive the reduction of water to produce hydrogen. The process can be divided into three main steps:
Light Absorption: The semiconductor catalyst absorbs photons, which excite electrons from the valence band to the conduction band, leaving behind holes. Charge Separation: The excited electrons and holes are separated and migrate to the surface of the catalyst. Redox Reactions: The electrons reduce protons in water to produce hydrogen, while the holes oxidize water to form oxygen.
