“…As shown in Figure 3d, the C 1s peak of SnO 2 /NGA comprises the four binding states, namely CÀ C (284.6 eV), CÀ N (285.2 eV), CÀ OÀ C (epoxy groups, 286.2 eV), and OÀ C=O (carboxyl, 288.7 eV) can be discerned. [27,37,38] In the case of SnO 2 @Sn/NGA, (Figure 3e) only CÀ C (284.6 eV), CÀ N (285.2 eV), and CÀ OÀ C (epoxy groups, 286.2 eV) can be discerned. The areal percentage of the O 1s peak is reduced from 36.2 % for the SnO 2 /NGA to 21.3 % for the SnO 2 @Sn/NGA.…”