The invention relates to a process for manufacturing a particulate titanium dioxide product, wherein hydrated titanium dioxide is precipitated from an aqueous solution of titanium oxychloride by adding to the solution titanium dioxide particles as crystal nuclei and the product obtained from the precipitation step is isolated and optionally calcined. The process is characterized by the addition of crystal nuclei to an aqueous solution of titanium oxychloride having a content of >90 g TiO.sub.2/l calculated as TiO.sub.2 and the performance of precipitation at a temperature below the boiling point of the said aqueous solution and at normal pressure. In addition, the invention relates to a titanium dioxide product prepared by using the process, the use of the product as a photocatalyst, and a photocatalyst, which comprises a titanium dioxide product prepared according to the invention.