Sol-Gel to Prepare Nitrogen Doped TiO₂ Nanocrystals with Exposed {001} Facets and High Visible-Light Photocatalytic Performance

Figure 2

TEM pictures of all samples ((a) S1-500, (b) S2-500, (c) S3-500, and (d) S4-500).

(a)

(b)

(c)

(d)