Photocatalytic water splitting is a process that uses photocatalysis for the dissociation of water (HO) into hydrogen () and oxygen (). The inputs are light energy (photons), water, and a catalyst(s).  The process is inspired by Photosynthesis, which converts water and carbon dioxide into oxygen and carbohydrates.  Water splitting using solar radiation has not been commercialized. Photocatalytic water splitting is done by dispersing photocatalyst particles in water or depositing them on a substrate, unlike Photoelectrochemical cell, which are assembled into a cell with a photoelectrode.  Hydrogen fuel production using water and light (photocatalytic water splitting), instead of petroleum, is an important renewable energy strategy.