Abstract
Amorphous and crystalline titanium-ammonium phosphates Ti2O2H(PO4)[(NH4)2PO4]2 were synthesized by the hydrothermal method. It is shown that the minimum temperature and processing time for the crystallization of the Ti2O2H(PO4)[(NH4)2PO4]2 phase are 160°C and 12 h, respectively. At the same time, NH4+ and \({\text{PO}}_{4}^{{3 + }}~\) ions are present in X-ray amorphous samples, similar to the crystalline compound, and during crystallization, a decrease in the content of water or hydroxyl groups and an increase in molar ratio of P : Ti are observed. X-ray amorphous samples consist of isotropic particles 10–15 nm in size, while crystalline samples contain diamond-shaped plates with smaller primary particles in their structure. X-ray amorphous and crystalline titanium-ammonium phosphates have low photocatalytic activity. The sun protection factor of X-ray amorphous samples, determined according to the international standard ISO 24443, is comparable to the sun protection factor of commercially available titanium dioxide.
