(a) x% Zr/N-TiO2(500), x = 0 to 10; (b) 0.6% Zr/N-TiO2 calcined at 400°C, 500°C, and 600°C. Figure 6b shows the visible light www.selleckchem.com/products/Trichostatin-A.html photocatalytic activities of 0.6% Zr/N-TiO2 samples calcined at different temperatures. The 0.6%Zr/N-TiO2 (400) sample calcined at 400°C shows a lower removal rate of ca. 12%. This lower
photocatalytic activity is due to its poor anatase crystallinity as shown in XRD results. Compared with the 0.6% Zr/N-TiO2 (600) sample, 0.6% Zr/N-TiO2(500) sample shows the highest removal rate of ca. 65%. We considered the best photocatalytic performance of Zr/N-TiO2(500) that is due to its higher crystallinity and high surface area according to the above XRD and TEM analysis. For click here comparison, Degussa P25 was also used as a precursor to prepare doped TiO2 samples. The photocatalytic activity of all TiO2 samples were investigated under visible light irradiation after N mono-doping and Zr/N co-doping. Figure 7 shows the removal rate of N mono-doped and Zr/N co-doped samples made from precursors of P25 and
NTA after 500°C calcination. For N mono-doping, the removal rate of N-doped P25 is 3% and the value increased to 12% for N-doped NTA-TiO2. We had compared the visible light photocatalytic activities of N-doped TiO2 made by different precursors such as P25 and NTA . The highest photocatalytic performance was found for N-doped TiO2 using NTA as precursor. In the Zr/N co-doping system, the removal rate of Zr/N-P25 is 9%, whereas the value of 0.6%Zr/N-NTA (500) increased to 65.3%. Figure 7 Degradation of propylene over 0.6% Zr/N-TiO 2 (500) synthesized from NTA and P25 respectively, as well as the N-NTA-TiO 2 and N-P25. The results showed that the Zr/N codoping significantly enhanced the visible light photocatalytic activities of TiO2 made by NTA precursor. It proves that NTA is a good candidate as a precursor for the preparation
of promising visible light TiO2 photocatalyst. As a special structural precursor, the process of loss of water and crystal structural transition during the calcination of NTA is expected the to be beneficial for Zr and N doping into the lattice of TiO2. Previously, the visible light absorption and photocatalytic activity of N-doped TiO2 sample N-NTA was found to co-determine by the formation of SETOV and N doping induced bandgap narrowing . Zr doping did not change the bandgap of TiO2 and exhibit no effect on the visible light absorption in our experiments. However, theoretical calculation showed Zr doping brought the N 2p gap states closer to valence band, enhancing the lifetimes of Brigatinib order photogenerated carriers . Moreover, Zr doping effectively suppressed the crystallite growth of nano-TiO2 and anatase to rutile phase transformation according to XRD and TEM analysis. Compared with Zr/N-P25, Zr/N-NTA(500) has the advantage of smaller crystallite size, larger surface area, and higher concentration of Zr and N dopant.