Fig. 2

Direct evidence of cobalt doping of SnS₂/RGO. a SEM image of SnS₂/RGO, scale bar: 1 μm. b SEM image of Sn_0.9Co_0.1S_x/RGO, scale bar: 1 μm. c TEM image of SnS₂/RGO, scale bar: 0.5 μm. d TEM image of SnS₂/RGO, scale bar: 5 nm. e TEM image of Sn_0.9Co_0.1S_x/RGO, scale bar: 0.5 μm. f TEM image of Sn_0.9Co_0.1S_x/RGO, scale bar: 5 nm. The inset is selected-area diffraction (SAED) pattern; g–k High-angle annular dark-field (HAADF) image and composite RGB element maps of SnS₂/RGO, and l–p HAADF image and composite RGB element maps of Sn_0.9Co_0.1S_x/RGO with corresponding TEM image. The scale bar for g–p represents 100 nm. Co, Sn and S elements are homogeneously distributed over the carbon and throughout the Sn_0.9Co_0.1S_x/RGO, suggesting the successful Co doping in the SnS₂ crystal lattice