The XPS results of the electrochemically treated rGO films indicate that Cr2O3 is synthesized within the nanocapillaries of the rGO stack. Within the nanocapillaries, the growth of Cr2O3 is confined in the direction perpendicular to the basal planes of rGO sheets. The width of the nanocapillaries and with that the available space for electrochemical synthesis is characterized by the interlayer distance of the stacked rGO film, which can be characterized with X-ray diffraction (XRD). Measured in dry state, the interlayer distance of the rGO stacks can indirectly represent the maximum thickness of materials (Cr2O3) created within the interlayer space. Upon immersion in water the interlayer distance of the rGO usually increases due of the uptake of water. Therefore, the wet interlayer distance indicate the available space during the electrochemical growth. To measure the evolution of the interlayer distance of the rGO during electrochemical process, a series of samples were prepared for different times (1 -15 min) at a fixed voltage of -1.8 V.