Abstract An amorphous phase TiO2 was fabricated via a fast and simple hydrolysis method and it was characterized with XRD, TEM, BET, UV–Vis, XPS and EPR. The as-prepared amorphous TiO2 has a specific surface area record-breaking 100 times that of crystal TiO2. The results show that the as-samples had better photocatalytic property, which was evaluated for gas-phase Hg0 oxidation under LED light, and photocatalytic efficiency reached up to 40%, which is 1.4 times that of commercial P25. It can be mainly attributed to the large specific surface area of amorphous TiO2 providing more reactive sites and its surface oxygen vacancies as carriers transport channels.