One-dimensional WO3 and its hydrate: One-step synthesis, structural and spectroscopic characterization

► WO3 nanorods prepared in a one step procedure. ► HCl (aq) enables phase pure WO3 nanorods. ► HCl (aq) induces significant reduction in dimension of and red shift in absorption edge of nanorods. ► W5+ detected in hydrothermal WO3 phase, the concentration of which increases in the hydrated phase. ► W5+ from the two phases due to different positive defects.