Fig. 2

Structural characterizations of topotactically reduced BiNS. a CV curve of BiOI showing its reduction to metallic Bi at cathodic potentials; b XRD and (inserted) schematic crystal structure of Bi; c SEM image; d, e TEM images at different magnifications; f SAED pattern of BiNS. Scale bar, 200 nm (c); 20 nm (d); 5 nm (e)