Porous Nd-doped In2O3 nanotubes with excellent formaldehyde sensing properties

(A) SEM images of (a, b) pure and (c, d) Nd-doped porous In2O3 nanotubes. (B) Responses curves of pure and Nd-doped porous In2O3 nanotube sensors to 100 ppm of formaldehyde at different operating temperatures.115