Figure 4From: Facile synthesis and enhanced visible light photocatalytic activity of N and Zr co-doped TiO2 nanostructures from nanotubular titanic acid precursorsUV–vis absorption spectra of precursor (P25 and NTA), Zr-doped NTA and Zr/N co-doped samples (P25 and NTA). Prepared at 500°C with 0.6% Zr content.Back to article page