Figure 2: Transmission and scanning electron microscopy and the corresponding element maps.

(a–d) Au NPs (20 nm)/HKUST-1 composite thin film; (e–h) Ferritin/HKUST-1 composite thin film; (i–l) [AuCl4]−/HKUST-1 composite thin film. The scale bars are (a) 500 nm, (b) 3 μm, (c,d) 2 μm, (e) 200 nm, (f) 3 μm, (g,l) 2 μm, respectively.