In 1967, Kenichi Honda, an associate professor of Tokyo University, and Akira Fujishima, a postgraduate student, discovered photocatalytic reaction, the result when UV light is irradiated to titanium dioxide, causing water to split into hydrogen and oxygen.
The reaction appears similar to photosynthesis, a process when oxygen is generated by light. They published a paper in the journal, Nature, in 1972.
Researchers in Europe and America took an interest in what was then called the “Honda-Fujishima effect“. Due to the discovery, energy and environmental applications broadened rapidly:
Outside walls of buildings with a self-cleaning function; Window glass that don’t fog; Development of deodorizers and air cleaners; Detoxication of waste fluids containing agricultural chemicals; Guardrails, sound insulation walls and paving blocks that decompose nitrogen oxide; Fluorescent lamps, Paint and steel boards that decompose indoor organic gases, etc.