Synthesis and photocatalytic properties of mesoporous tantalum oxynitride

Abstract

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).