Photocatalytic decomposition of acetone using LaTi(O,N)3 nanoparticles under visible light irradiation

Nanoparticles of the oxynitride perovskite LaTi(O,N) 3 have been synthesized by the polyol technique and subsequent ammonolysis at different temperatures, namely 800, 870, 920 and 1000 degrees C. The obtained compounds were investigated by XRD, TEM, BET, and UV-Vis spectroscopy. The nitrogen content was measured by ERDA analysis. Even at the lowest reaction temperature well crystalline single phase oxynitrides were obtained. With increasing nitridation temperature the colors of the samples changed from orange to red and brown resulting from a decrease of the optical band gap. This color variation is accompanied by a higher nitrogen content, an increase in the particle sizes and a reduction in the BET surface area. The photocatalyzed decomposition of acetone under visible light (lambda > 420 nm) was measured by in situ infrared spectroscopy. The sample reacted at 870 degrees C showed the highest activity. The photocatalytic properties of the different samples are compared and the influence of the physical properties on the photocatalytic efficiency of the samples is discussed.