Fig. 2: The role of citrate as a facet-controlling agent for the growth of SnO2 nanocrystals.

a XRD patterns of SnO2 samples obtained with and without sodium citrate. b The calculated adsorption energies of citrate on SnO2 with different facets. c C1s XPS spectrum and d thermogravimetric curve of the SnO2/graphene nanocomposite