LAUSR

The effect of the conditions of ammonolysis of mesoporous magnesiothermic tantalum powders with the specific surface area of 56–63 m2 g–1 on phase composition and specific surface area of the products is studied in the temperature range of 400–900°C. The ammonolysis products are shown to be X-ray amorphous at 400–600°C. At the heating rate of 20 K/min, the nitrogen content in these products is 5.4–7.3% and the specific surface area is 42–35 m2 g–1, while at heating rate of 8 K/min these parameters are 2.4–5.4% and 56–49 m2 g–1, respectively. The crystalline phase of tantalum oxynitride TaON is formed at a temperature of 700°C and above. The resulting materials exhibit a high photocatalytic activity in the reactions of ferroin and methylene blue degradation under irradiation with visible light (λ ≥ 420 nm).