Titanium dioxide (TiO₂)

Titanium dioxide (TiO₂) is a naturally occurring compound made from titanium and oxygen. It is commonly produced as a fine white powder and is widely used as a pigment in paints, coatings, plastics, paper, cosmetics and some food products because of its brightness, opacity and resistance to ultraviolet radiation. Titanium dioxide also has photocatalytic properties, meaning it can use light energy to trigger chemical reactions. This makes it relevant to technologies such as air and water purification, self-cleaning surfaces, solar cells and hydrogen production. In green hydrogen research, titanium dioxide can act as a photocatalyst that helps split water-related molecules when exposed to light. However, standard titanium dioxide absorbs mainly ultraviolet light and may lose energy through rapid electron recombination. Researchers therefore modify its structure, introduce defects or add metals to improve light absorption, charge transfer and hydrogen output.