Figure 3.

Composition characterizations of Nb₂O₅ nanotube products: XRD (a) and EDX (b) patterns of single-crystalline nanoporous Nb₂O₅ nanotubes. All the peaks in Figure 3a totally overlap with those of pure Nb₂O₅ (compare reference lines, JCPDS no. 30-0873) and no evidence of any impurity was detected.