The interatomic distance (Cr-Cr1) in the best fit of the Cr2O3/rGO-1.8V-1min and Cr2O3/rGO-1.8V-15min are 2.52 ± 0.05 Å and 2.49 ± 0.07 Å, respectively (Table. S6). This is smaller than that of the reference Cr2O3 (2.68 ± 0.04 Å). The reduced interatomic distances might be explained by defects and strain induced by the space confinement within the rGO layers and reduced dimensionality compared to bulk Cr2O3. Nevertheless, the distances of Cr-O and Cr-Cr2 in the synthesized samples show negligibly small differences with the bulk Cr2O3. It is worth to mention that the third shell peak (> 3 Å), representing Cr-Cr3 path and other Cr-O paths, is damped compared to the bulk sample. This means that the synthesized Cr2O3 has a number of vacancies. Note that the weaker intensity of Cr-O path in the synthesized Cr2O3 indicates that there are a number of oxygen vacancies. The existence of these oxygen vacancies is further confirmed by XPS depth profile of the O1s peak showing oxygen vacancy shoulders ~531 eV (Figure ).