Tantalum (oxy)nitrides: preparation, characterisation and enhancement of photo-Fenton-like degradation of atrazine under visible light.

Tantalum (oxy)nitrides were prepared by the nitridation of Ta(2)O(5) and were added to a photo-Fenton-like system to enhance Fe(3+) reduction and atrazine degradation under visible light. The samples were characterized by XRD, XPS, DRS and BET analyses. XPS analysis showed that the nitrogen content of the tantalum (oxy)nitride samples increased noticeably with the nitridation temperature and nitridation time but slightly with the flow rate of NH(3). XRD results showed Ta(2)O(5) was first converted to TaON and then to Ta(3)N(5) when the nitridation temperature increased. DRS analysis showed that the sample obtained at 800°C displayed the strongest absorption of visible light. However, the ability of the tantalum (oxy)nitrides to reduce Fe(3+) did not increase continuously with the nitrogen content. Sample 7 (700°C, [Formula: see text] , 6h) showed the highest level of photocatalytic activity for Fe(3+) reduction. This is because the photocatalytic activity of TaON for Fe(3+) reduction is higher than that of Ta(3)N(5). And a slight synergetic effect was observed between TaON and Ta(3)N(5). With the addition of sample 7, H(2)O(2) decomposition and atrazine degradation were significantly accelerated in a photo-Fenton-like system under visible light. The regenerated tantalum (oxy)nitrides catalyst displayed considerably stable performance for atrazine degradation.